Publications by authors named "Dong Won Kim"

230 Publications

Conversion of an oral to nasal intubation in difficult nasal anatomy patients: two case reports.

BMC Anesthesiol 2021 Mar 9;21(1):72. Epub 2021 Mar 9.

Department of Anesthesiology and Pain Medicine, Hanyang University Hospital, 222, Wangsimni-ro, Seongdonggu, Seoul, 133-792, Republic of Korea.

Background: Nasal intubation is indispensable for some cases that require intraoral surgical access, and the fiberoptic bronchoscope is the best tool for difficult airways. However, fiberoptic bronchoscopy is not always possible in cases with altered pharyngeal anatomy.

Case Presentation: In this report, we introduce a novel technique for retrograde endotracheal oral-to-nasal conversion with an ordinary endotracheal tube exchange catheter. A 49-year-old male with a fractured mandible angle and symphysis was scheduled to undergo mandible reconstruction. Secondly, a 45-year-old male who had a bone defect in the mandible angle and ramus was scheduled for mandible and oral cavity reconstruction. We chose to intubate orally first and successfully converted the endotracheal tube from oral to nasal retrogressively using a tube exchange catheter.

Conclusions: Our simple and safe technique, which use a tube exchange catheter retrogressively, provides an alternative method for a difficult airway in which the fiberscope is not helpful.
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http://dx.doi.org/10.1186/s12871-021-01298-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7941715PMC
March 2021

Atoh7-independent specification of retinal ganglion cell identity.

Sci Adv 2021 Mar 12;7(11). Epub 2021 Mar 12.

National Institute of Mental Health (NIMH), National Institutes of Health (NIH), Bethesda, MD, USA.

Retinal ganglion cells (RGCs) relay visual information from the eye to the brain. RGCs are the first cell type generated during retinal neurogenesis. Loss of function of the transcription factor , expressed in multipotent early neurogenic retinal progenitors leads to a selective and essentially complete loss of RGCs. Therefore, is considered essential for conferring competence on progenitors to generate RGCs. Despite the importance of Atoh7 in RGC specification, we find that inhibiting apoptosis in deficient mice by loss of function of only modestly reduces RGC numbers. Single-cell RNA sequencing of -deficient retinas shows that RGC differentiation is delayed but that the gene expression profile of RGC precursors is grossly normal. -deficient RGCs eventually mature, fire action potentials, and incorporate into retinal circuitry but exhibit severe axonal guidance defects. This study reveals an essential role for in RGC survival and demonstrates -dependent and independent mechanisms for RGC specification.
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http://dx.doi.org/10.1126/sciadv.abe4983DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7954457PMC
March 2021

Temperature and species-dependent regulation of browning in retrobulbar fat.

Sci Rep 2021 Feb 4;11(1):3094. Epub 2021 Feb 4.

Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA.

Retrobulbar fat deposits surround the posterior retina and optic nerve head, but their function and origin are obscure. We report that mouse retrobulbar fat is a neural crest-derived tissue histologically and transcriptionally resembles interscapular brown fat. In contrast, human retrobulbar fat closely resembles white adipose tissue. Retrobulbar fat is also brown in other rodents, which are typically housed at temperatures below thermoneutrality, but is white in larger animals. We show that retrobulbar fat in mice housed at thermoneutral temperature show reduced expression of the brown fat marker Ucp1, and histological properties intermediate between white and brown fat. We conclude that retrobulbar fat can potentially serve as a site of active thermogenesis, that this capability is both temperature and species-dependent, and that this may facilitate regulation of intraocular temperature.
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http://dx.doi.org/10.1038/s41598-021-82672-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7862600PMC
February 2021

Dual midbrain and forebrain origins of thalamic inhibitory interneurons.

Elife 2021 Feb 1;10. Epub 2021 Feb 1.

Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom.

The ubiquitous presence of inhibitory interneurons in the thalamus of primates contrasts with the sparsity of interneurons reported in mice. Here, we identify a larger than expected complexity and distribution of interneurons across the mouse thalamus, where all thalamic interneurons can be traced back to two developmental programmes: one specified in the midbrain and the other in the forebrain. Interneurons migrate to functionally distinct thalamocortical nuclei depending on their origin: the abundant, midbrain-derived class populates the first and higher order sensory thalamus while the rarer, forebrain-generated class is restricted to some higher order associative regions. We also observe that markers for the midbrain-born class are abundantly expressed throughout the thalamus of the New World monkey marmoset. These data therefore reveal that, despite the broad variability in interneuron density across mammalian species, the blueprint of the ontogenetic organisation of thalamic interneurons of larger-brained mammals exists and can be studied in mice.
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http://dx.doi.org/10.7554/eLife.59272DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7906600PMC
February 2021

Gene regulatory networks controlling differentiation, survival, and diversification of hypothalamic Lhx6-expressing GABAergic neurons.

Commun Biol 2021 Jan 21;4(1):95. Epub 2021 Jan 21.

Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.

GABAergic neurons of the hypothalamus regulate many innate behaviors, but little is known about the mechanisms that control their development. We previously identified hypothalamic neurons that express the LIM homeodomain transcription factor Lhx6, a master regulator of cortical interneuron development, as sleep-promoting. In contrast to telencephalic interneurons, hypothalamic Lhx6 neurons do not undergo long-distance tangential migration and do not express cortical interneuronal markers such as Pvalb. Here, we show that Lhx6 is necessary for the survival of hypothalamic neurons. Dlx1/2, Nkx2-2, and Nkx2-1 are each required for specification of spatially distinct subsets of hypothalamic Lhx6 neurons, and that Nkx2-2+/Lhx6+ neurons of the zona incerta are responsive to sleep pressure. We further identify multiple neuropeptides that are enriched in spatially segregated subsets of hypothalamic Lhx6 neurons, and that are distinct from those seen in cortical neurons. These findings identify common and divergent molecular mechanisms by which Lhx6 controls the development of GABAergic neurons in the hypothalamus.
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http://dx.doi.org/10.1038/s42003-020-01616-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7820013PMC
January 2021

Synergistically Improved Thermoelectric Energy Harvesting of Edge-Oxidized-Graphene-Bridged N-Type Bismuth Telluride Thick Films.

ACS Appl Mater Interfaces 2021 Feb 21;13(4):5125-5132. Epub 2021 Jan 21.

School of Materials Science and Engineering, Kyungpook National University, Daegu 41566, Republic of Korea.

Power generation through the thermoelectric (TE) effect in small-sized devices requires a submillimeter-thick film that is beneficial to effectively maintain Δ compared with a micron-scale thin film. However, most TE thick films, which are fabricated using printing technologies, suffer from low electrical conductivity due to the porous structures formed after sintering of the organic binder-mixed TE ink. In this study, we report an n-type TE thick film fabricated through bar-coating of the edge-oxidized-graphene (EOG)-dispersed BiTeSe (BTS) paste with copper dopants. We have found that EOG provides the conducting pathway for carriers through electrical bridging between the separated BTS grains in porous TE thick films. The simultaneous enhancement in electrical conductivity and the Seebeck coefficient of the EOG-bridged TE film result in a maximum power factor of 1.54 mW·m·K with the addition of 0.01 wt % EOG. Furthermore, the single element made of an n-type EOG-bridged BTS exhibits a superior output power of 1.65 μW at Δ = 80 K. These values are 5 times higher than those of bare BTS films. Our results clearly indicate that the utilization of EOG with a metal dopant exerts a synergistic effect for enhancing the electrical output performance of n-type TE thick films for thermal energy harvesters.
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http://dx.doi.org/10.1021/acsami.0c20509DOI Listing
February 2021

Understanding Excess Li Storage beyond LiC in Reduced Dimensional Scale Graphene.

ACS Nano 2021 Jan 17;15(1):797-808. Epub 2020 Dec 17.

Department of Energy Engineering, Gyeongnam National University of Science and Technology, Jinju-si, Gyeongnam 52725, South Korea.

A phenomenon is observed in which the electrochemical performances of porous graphene electrodes show unexpectedly increasing capacities in the Li storage devices. However, despite many studies, the cause is still unclear. Here, we systematically present the reason for the capacity enhancements of the pristine graphene anode under functional group exclusion through morphological control and crystal structure transformation. The electrochemical synergy of both the edge effect and surface effect of the reduced dimensional scale graphene in an open-porous structure facilitates significantly enhanced capacity through multidimensional Li-ion accessibility and accumulation of Li atoms. Furthermore, the Stone-Wales defects boosted during Li insertion and extraction promote a capacity elevation beyond the theoretical capacity of the carbon electrode even after long-term cycles at high C-rates. As a result, the morphologically controlled graphene anode delivers the highest reversible capacity of 3074 mA h g with a 163% capacity increase after 2000 cycles at 5 C. It also presents a gradually increasing capacity up to 1102 mA h g even at 50 C without an evident capacity fading tendency. This study provides valuable information into the practical design of ultralight and high-rate energy storage devices.
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http://dx.doi.org/10.1021/acsnano.0c07173DOI Listing
January 2021

Electrical Resistivity Measurements of Reinforced Concrete Slabs with Delamination Defects.

Sensors (Basel) 2020 Dec 11;20(24). Epub 2020 Dec 11.

Department of ICT integrated Ocean Smart Cities Engineering, Dong-A University, Busan 225, Korea.

The main objectives of this research are to evaluate the effects of delamination defects on the measurement of electrical resistivity of reinforced concrete slabs through analytical and experimental studies in the laboratory, and to propose a practical guide for electrical resistivity measurements on concrete with delamination defects. First, a 3D finite element model was developed to simulate the variation of electric potential field in concrete over delamination defects with various depths and lateral sizes. Second, for experimental studies, two reinforced concrete slab specimens (1500 mm (width) by 1500 mm (length) by 300 mm (thickness)) with artificial delamination defects of various dimensions and depths were fabricated. Third, the electrical resistivity of concrete over delamination defects in the numerical simulation models and the two concrete slab specimens were evaluated by using a 4-point Wenner probe in accordance with AASHTO (American Association of State Highway and Transportation Office) T-358. It was demonstrated from analytical and experimental studies in this study that shallow (50 mm depth) and deep (250 mm depth) delamination defects resulted in higher and lower electrical resistivity (ER) values, respectively, as compared to measurements performed on solid concrete locations. Furthermore, the increase in size of shallow defects resulted in an increase in concrete resistivity, whereas the increase in sizes of deep delamination defects yielded opposite results. In addition, measurements done directly above the steel reinforcements significantly lowered ER values. Lastly, it was observed from experimental studies that the effect of delamination defects on the values of electrical resistivity decreases as the saturation level of concrete increases.
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http://dx.doi.org/10.3390/s20247113DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7764579PMC
December 2020

Characterization of mWake expression in the murine brain.

J Comp Neurol 2021 Jun 10;529(8):1954-1987. Epub 2020 Nov 10.

Department of Neurology, Johns Hopkins University, Baltimore, Maryland, USA.

Structure-function analyses of the mammalian brain have historically relied on anatomically-based approaches. In these investigations, physical, chemical, or electrolytic lesions of anatomical structures are applied, and the resulting behavioral or physiological responses assayed. An alternative approach is to focus on the expression pattern of a molecule whose function has been characterized and then use genetic intersectional methods to optogenetically or chemogenetically manipulate distinct circuits. We previously identified WIDE AWAKE (WAKE) in Drosophila, a clock output molecule that mediates the temporal regulation of sleep onset and sleep maintenance. More recently, we have studied the mouse homolog, mWAKE/ANKFN1, and our data suggest that its basic role in the circadian regulation of arousal is conserved. Here, we perform a systematic analysis of the expression pattern of mWake mRNA, protein, and cells throughout the adult mouse brain. We find that mWAKE labels neurons in a restricted, but distributed manner, in multiple regions of the hypothalamus (including the suprachiasmatic nucleus, dorsomedial hypothalamus, and tuberomammillary nucleus region), the limbic system, sensory processing nuclei, and additional specific brainstem, subcortical, and cortical areas. Interestingly, mWAKE is also observed in non-neuronal ependymal cells. In addition, to describe the molecular identities and clustering of mWake cells, we provide detailed analyses of single cell RNA sequencing data from the hypothalamus, a region with particularly significant mWAKE expression. These findings lay the groundwork for future studies into the potential role of mWAKE cells in the rhythmic control of diverse behaviors and physiological processes.
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http://dx.doi.org/10.1002/cne.25066DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8009828PMC
June 2021

Gene regulatory networks controlling vertebrate retinal regeneration.

Science 2020 11 1;370(6519). Epub 2020 Oct 1.

Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.

Injury induces retinal Müller glia of certain cold-blooded vertebrates, but not those of mammals, to regenerate neurons. To identify gene regulatory networks that reprogram Müller glia into progenitor cells, we profiled changes in gene expression and chromatin accessibility in Müller glia from zebrafish, chick, and mice in response to different stimuli. We identified evolutionarily conserved and species-specific gene networks controlling glial quiescence, reactivity, and neurogenesis. In zebrafish and chick, the transition from quiescence to reactivity is essential for retinal regeneration, whereas in mice, a dedicated network suppresses neurogenic competence and restores quiescence. Disruption of nuclear factor I transcription factors, which maintain and restore quiescence, induces Müller glia to proliferate and generate neurons in adult mice after injury. These findings may aid in designing therapies to restore retinal neurons lost to degenerative diseases.
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http://dx.doi.org/10.1126/science.abb8598DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7899183PMC
November 2020

Synergetic enhancement in the reactivity and stability of surface-oxide-free fine Al particles covered with a polytetrafluoroethylene nanolayer.

Sci Rep 2020 Sep 3;10(1):14560. Epub 2020 Sep 3.

3D Printing Materials Research Center, Korea Institute of Materials Science, 797 Changwondaero, Seongsan-gu, Changwon, Gyeongnam, 51508, Republic of Korea.

Surface oxide (AlO) of reactive fine aluminum (Al) particles for solid fuels, propellants, and brazing materials often restricted oxidative performance, though the passivation film acts to protect Al particles from exploding. Here, we report fine Al particles fully covered with a polytetrafluoroethylene (PTFE) layer instead of an AlO film on the surface. This advance is based on the introduction of strong Al-F bonds, known to be an alternative to the Al-O bonds of surface oxides. The DSC results on the PTFE-coated Al particles exhibit higher reactive-exothermic enthalpy energy (12.26 kJ g) than 4.85 kJ g by uncoated Al particles. The artificial aging test of the PTFE layer on the Al particles show long-time stability to the external circumstance compared to those by AlO. The activation energy for oxidation was investigated from cyclic voltammetry assessment and the measured peak potentials of the anode curve for PTFE/Al (- 0.45 V) and uncoated Al (- 0.39 V) are achieved, respectively. This means that the PTFE layer is more stable against a sudden explosion of Al particles compared to AlO. These results are very useful given its capability to control both the reactivity and stability levels during the oxidation of Al particles for practical applications.
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http://dx.doi.org/10.1038/s41598-020-71162-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7471686PMC
September 2020

The cellular and molecular landscape of hypothalamic patterning and differentiation from embryonic to late postnatal development.

Nat Commun 2020 08 31;11(1):4360. Epub 2020 Aug 31.

Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.

The hypothalamus is a central regulator of many innate behaviors essential for survival, but the molecular mechanisms controlling hypothalamic patterning and cell fate specification are poorly understood. To identify genes that control hypothalamic development, we have used single-cell RNA sequencing (scRNA-Seq) to profile mouse hypothalamic gene expression across 12 developmental time points between embryonic day 10 and postnatal day 45. This identified genes that delineated clear developmental trajectories for all major hypothalamic cell types, and readily distinguished major regional subdivisions of the developing hypothalamus. By using our developmental dataset, we were able to rapidly annotate previously unidentified clusters from existing scRNA-Seq datasets collected during development and to identify the developmental origins of major neuronal populations of the ventromedial hypothalamus. We further show that our approach can rapidly and comprehensively characterize mutants that have altered hypothalamic patterning, identifying Nkx2.1 as a negative regulator of prethalamic identity. These data serve as a resource for further studies of hypothalamic development, physiology, and dysfunction.
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http://dx.doi.org/10.1038/s41467-020-18231-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7459115PMC
August 2020

Prognostic Factors of Long-Term Outcomes in Endodontic Microsurgery: A Retrospective Cohort Study over Five Years.

J Clin Med 2020 Jul 13;9(7). Epub 2020 Jul 13.

Department of Conservative Dentistry, Dental Research Institute, Seoul National University Dental Hospital, Seoul National University School of Dentistry, Seoul 03080, Korea.

The aim of this study was to analyze the long-term outcomes of endodontic microsurgeries in a cohort and identify their association with prognostic factors. A cohort of endodontic microsurgeries followed up periodically with complete clinical and radiographic records for at least 5 years were reviewed retrospectively. Their survival and healing status and profile characteristics were analyzed by Pearson chi-square test and logistic regression (α = 0.05) to identify prognostic factors that influenced outcomes. Of 652 cases in the cohort, 225 (34.5%) were included. The mean follow-up period was 90.4 months (range, 60-168 months). The long-term success rate was 80.5%, and the 5-year survival rate was 83.5%. Logistic regression showed higher success in anteriors compared to molars (OR = 5.405, (95% CI, 1.663-17.571; = 0.005)) and in teeth with crown restorations (OR = 10.232, (95% CI, 3.374-31.024; < 0.001)). Conversely, lower success was found in teeth with periodontal disease (OR = 0.170, (95% CI, 0.032-0.900; = 0.037)) and maxillary sinus involvement (OR = 0.187, (95% CI, 0.035-0.994; = 0.049)). Endodontic microsurgery has a highly favorable long-term outcome. Tooth position, crown restoration, periodontal disease, and maxillary sinus involvement were identified as main prognostic factors.
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http://dx.doi.org/10.3390/jcm9072210DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7409012PMC
July 2020

A single cell transcriptional atlas of early synovial joint development.

Development 2020 07 20;147(14). Epub 2020 Jul 20.

Institute for Cell Engineering, Johns Hopkins School of Medicine, Baltimore MD 21205, USA

Synovial joint development begins with the formation of the interzone, a region of condensed mesenchymal cells at the site of the prospective joint. Recently, lineage-tracing strategies have revealed that Gdf5-lineage cells native to and from outside the interzone contribute to most, if not all, of the major joint components. However, there is limited knowledge of the specific transcriptional and signaling programs that regulate interzone formation and fate diversification of synovial joint constituents. To address this, we have performed single cell RNA-Seq analysis of 7329 synovial joint progenitor cells from the developing murine knee joint from E12.5 to E15.5. By using a combination of computational analytics, hybridization and characterization of prospectively isolated populations, we have identified the transcriptional profiles of the major developmental paths for joint progenitors. Our freely available single cell transcriptional atlas will serve as a resource for the community to uncover transcriptional programs and cell interactions that regulate synovial joint development.
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http://dx.doi.org/10.1242/dev.185777DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7390639PMC
July 2020

Cinnamon-Derived Hierarchically Porous Carbon as an Effective Lithium Polysulfide Reservoir in Lithium-Sulfur Batteries.

Nanomaterials (Basel) 2020 Jun 22;10(6). Epub 2020 Jun 22.

School of Chemical Engineering, Chonnam National University, Gwang-ju, 61186, Korea.

Lithium-sulfur batteries are attractive candidates for next generation high energy applications, but more research works are needed to overcome their current challenges, namely: (a) the poor electronic conductivity of sulfur, and (b) the dissolution and migration of long-chain polysulfides. Inspired by eco-friendly and bio-derived materials, we synthesized highly porous carbon from cinnamon sticks. The bio-carbon had an ultra-high surface area and large pore volume, which serves the dual functions of making sulfur particles highly conductive and acting as a polysulfide reservoir. Sulfur was predominantly impregnated into pores of the carbon, and the inter-connected hierarchical pore structure facilitated a faster ionic transport. The strong carbon framework maintained structural integrity upon volume expansion, and the unoccupied pores served as polysulfide trapping sites, thereby retaining the polysulfide within the cathode and preventing sulfur loss. These mechanisms contributed to the superior performance of the lithium-sulfur cell, which delivered a discharge capacity of 1020 mAh g at a 0.2C rate. Furthermore, the cell exhibited improved kinetics, with an excellent cycling stability for 150 cycles with a very low capacity decay of 0.10% per cycle. This strategy of combining all types of pores (micro, meso and macro) with a high pore volume and ultra-high surface area had a synergistic effect on improving the performance of the sulfur cathode.
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http://dx.doi.org/10.3390/nano10061220DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7353079PMC
June 2020

Refractory Ventricular Fibrillation Treated with Double Simultaneous Defibrillation: Pilot Study.

Emerg Med Int 2020 27;2020:5470912. Epub 2020 May 27.

Department of Emergency Medicine, Seoul National University Bundang Hospital, Seongnam, Gyeonggi 13620, Republic of Korea.

Introduction: Refractory shockable rhythm has a high mortality rate and poor neurological outcome. Treatments for refractory shockable rhythm presenting after defibrillation and medical treatment are not definite. We conducted research on the application of double simultaneous defibrillation (DSiD) for refractory shockable rhythms.

Methods: This is a retrospective pilot study performed using medical records from 1 January 2016 to 31 December 2017. The prephase was from January to December 2016. The post-phase was from January to December 2017. During the prephase, we conducted conventional defibrillation with one defibrillator, and during the post-phase, we conducted DSiD using two defibrillators. Primary outcome was survival to hospital discharge. Secondary outcomes included survival to hospital admission and good neurological outcome at 12 months. Statistical analysis was conducted using Fisher's exact test. Data were regarded statistically significant when < 0.05.

Result: A total of 38 patients were included. Twenty-one patients underwent conventional defibrillation, and 17 underwent DSiD. The DSiD group had a higher survival to admission rate (14/17 (82.4%) vs. 6/21 (28.6%), =0.001) and showed a trend for higher survival to discharge (7/17 (41.2%) vs. 3/21 (14.3%), =0.078). Good neurological outcome at 12 months of the DSiD group was higher than that of the conventional defibrillation group, but the difference was not statistically significant (5/17 (29.4%) vs 2/21 (9.5%), =0.207).

Conclusion: In patients with refractory shockable rhythms, DSiD has increased survival to hospital admission and a trend of increased survival to hospital discharge. However, DSiD did not improve neurological outcome at 12 months.
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http://dx.doi.org/10.1155/2020/5470912DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7273448PMC
May 2020

Risk management-based security evaluation model for telemedicine systems.

BMC Med Inform Decis Mak 2020 06 10;20(1):106. Epub 2020 Jun 10.

Information Security Department, Korea University, Seoul, Republic of Korea.

Background: Infectious diseases that can cause epidemics, such as COVID-19, SARS-CoV, and MERS-CoV, constitute a major social issue, with healthcare providers fearing secondary, tertiary, and even quaternary infections. To alleviate this problem, telemedicine is increasingly being viewed as an effective means through which patients can be diagnosed and medications prescribed by doctors via untact Thus, concomitant with developments in information and communication technology (ICT), medical institutions have actively analyzed and applied ICT to medical systems to provide optimal medical services. However, with the convergence of these diverse technologies, various risks and security threats have emerged. To protect patients and improve telemedicine quality for patient safety, it is necessary to analyze these risks and security threats comprehensively and institute appropriate countermeasures.

Methods: The security threats likely to be encountered in each of seven telemedicine service areas were analyzed, and related data were collected directly through on-site surveys by a medical institution. Subsequently, an attack tree, the most popular reliability and risk modeling approach for systematically characterizing the potential risks of telemedicine systems, was examined and utilized with the attack occurrence probability and attack success probability as variables to provide a comprehensive risk assessment method.

Results: In this study, the most popular modelling method, an attack tree, was applied to the telemedicine environment, and the security concerns for telemedicine systems were found to be very large. Risk management and evaluation methods suitable for the telemedicine environment were identified, and their benefits and potential limitations were assessed.

Conclusion: This research should be beneficial to security experts who wish to investigate the impacts of cybersecurity threats on remote healthcare and researchers who wish to identify new modeling opportunities to apply security risk modeling techniques.
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http://dx.doi.org/10.1186/s12911-020-01145-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7286211PMC
June 2020

Double MgO-Based Perpendicular Magnetic Tunnel Junction for Artificial Neuron.

Front Neurosci 2020 30;14:309. Epub 2020 Apr 30.

Department of Nanoscale Semiconductor Engineering, Hanyang University, Seoul, South Korea.

A perpendicular spin transfer torque (p-STT)-based neuron was developed for a spiking neural network (SNN). It demonstrated the integration behavior of a typical neuron in an SNN; in particular, the integration behavior corresponding to magnetic resistance change gradually increased with the input spike number. This behavior occurred when the spin electron directions between double CoFeB free and pinned layers in the p-STT-based neuron were switched from parallel to antiparallel states. In addition, a neuron circuit for integrate-and-fire operation was proposed. Finally, pattern-recognition simulation was performed for a single-layer SNN.
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http://dx.doi.org/10.3389/fnins.2020.00309DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7204637PMC
April 2020

Quasi-Solid-State Electrolyte Synthesized Using a Thiol-Ene Click Chemistry for Rechargeable Lithium Metal Batteries with Enhanced Safety.

ACS Appl Mater Interfaces 2020 Apr 14;12(17):19553-19562. Epub 2020 Apr 14.

Battery R&D, LG Chem, Daejeon 34122, Republic of Korea.

Liquid electrolytes currently used in lithium-ion batteries have critical drawbacks such as high flammability, high reactivity toward electrode materials, and solvent leakage. To overcome these issues, most recent research has focused on synthesis and characterization of highly conductive gel-type polymer electrolytes containing large numbers of organic solvents in the polymer matrix. There are still many hurdles to overcome, however, before they can be applied to commercial-level lithium-ion batteries. Since a large amount of organic solvent is required to achieve high ionic conductivity, battery safety is not significantly enhanced. In our study, we synthesized highly conductive quasi-solid-state electrolytes (QSEs) containing an ionically conductive oligomer (polycaprolactone triacrylate) and a small amount of organic solvent by employing click chemistry. In the QSE, polycaprolactone participates in dissociation of lithium salt and migration of lithium ions, resulting in high ionic conductivity. The Li/LiNiCoMnO cell that used this QSE exhibited good cycling performance and enhanced thermal stability, and durability; no organic solvent leakage was observed even under high pressure.
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http://dx.doi.org/10.1021/acsami.0c02706DOI Listing
April 2020

Ultrasmall SnS Quantum Dots Anchored onto Nitrogen-Enriched Carbon Nanospheres as an Advanced Anode Material for Sodium-Ion Batteries.

ACS Appl Mater Interfaces 2020 Feb 29;12(6):7114-7124. Epub 2020 Jan 29.

Department of Chemical Engineering , Hanyang University , Seoul 04763 , Republic of Korea.

Structural pulverization of metal chalcogenides such as Sn-based compounds is a serious issue for development of high-performance anode materials and results in serious capacity fading during continuous charge and discharge cycles. In this work, we synthesize ultrasmall SnS quantum dots (QDs) anchored onto nitrogen-enriched carbon (NC) nanospheres through facile hydrothermal and carbonization processes to prepare a progressive anode material for sodium-ion batteries. The optimized SnS QDs@NC electrode delivered an initial discharge capacity of 281 mAh g at 100 mA g and exhibited excellent cycling stability with a capacity retention of 75% after 500 cycles at a high current density of 1000 mA g. Ex situ XRD, XPS, FE-SEM, TEM measurements, and kinetics study were performed to unveil the sodium storage mechanism of the SnS QDs@NC electrode. A sodium-ion full cell assembled with an SnS QDs@NC anode and a NaV(PO) cathode exhibited high capacity and good cycling stability. Such a superior electrochemical performance of SnS QDs@NC can be attributed to the synergistic effects of NC and SnS QDs where NC serves as a conducting matrix to support SnS QDs and helps avoid structural degradation. This work provides a promising strategy to resolve the pulverization issue of alloying and conversion-type anode materials.
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http://dx.doi.org/10.1021/acsami.9b18997DOI Listing
February 2020

Reporting Quality Analysis of Randomized Controlled Trials in Journal of Neurosurgical Anesthesiology: A Methodological Assessment.

J Neurosurg Anesthesiol 2021 Apr;33(2):154-160

Department of Anesthesiology and Pain Medicine, Hanyang University Hospital, College of Medicine, Seoul, Republic of Korea.

Background: Randomized controlled trials (RCTs) are considered to provide high levels of evidence to optimize decision-making for patient care, although there can be a risk bias in their design, conduct, and analysis. Quality assessment of RCTs is necessary to assess whether they provide reliable results with little bias.

Materials And Methods: We assessed the reporting quality of RCTs published in the Journal of Neurosurgical Anesthesiology (JNA) between January 1, 2000 and December 31, 2017 using the Jadad scale, van Tulder scale, and Cochrane Collaboration Risk of Bias Tool (CCRBT).

Results: We identified 130 RCTs and 570 original articles. Among the 130 RCTs, 92 (70.8%) presented an appropriate blinding method, and 70 (53.8%) described an appropriate allocation method. For the entire period, the percentages of high-quality reporting articles were 71.5%, 73.1%, and 13.8% in the Jadad scale, van Tulder scale, and CCRBT assessments, respectively. There was an improvement in the van Tulder scale over time (coefficients [95% confidence interval {CI}]=0.08 [0.01-0.15]; P=0.02). Appropriate reporting of allocation in the Jadad scale (coefficients [95% CI]=1.68 [1.28-2.07]; P<0.001) and van Tulder scale (coefficients [95% CI]=2.34 [1.97-2.70]; P<0.001), and reporting of blinding in the Jadad (coefficients [95% CI]=1.09 [0.66-1.52]; P<0.001) and van Tulder scores (coefficients [95% CI]=1.85 [1.45-2.25]; P<0.001), were associated with high-quality reporting.

Conclusions: The ratio of high-quality reporting RCTs in JNA was consistently high compared with other journals. Thorough consideration of allocation concealment during the peer review process can further improve the reporting quality of RCTs in JNA.
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http://dx.doi.org/10.1097/ANA.0000000000000662DOI Listing
April 2021

Which is the most effective pristine graphene electrode for energy storage devices: aerogel or xerogel?

Nanoscale 2019 Oct;11(38):17563-17570

Environmental Fate & Exposure Research Group, Korea Institute of Toxicology, Jinju-si, Gyeongnam 52834, South Korea.

The morphological design of graphene materials is definitely important since their electrochemical properties as an electrode in energy storage devices are mainly dominated by their charge accessibility and active area. In this work, we present a systematic investigation on the prospects of a pristine graphene aerogel and a pristine graphene xerogel as electrode materials for both supercapacitors and lithium-ion batteries. We confirm that the graphene aerogel has a significantly higher surface area, needed for effective charge storage, than the xerogel, which offers a clear advantage for supercapacitors. In terms of battery performance, the quality of the pristine graphene raw materials is a more critical factor than their shape owing to the lithium intercalation mechanism. As a result, the graphene aerogel supercapacitors exhibited a specific capacitance of about 700 F g-1 at 10 mV s-1 in 1 M LiPF6 electrolyte, which is 3.6 times higher than the values for the xerogel devices. On the other hand, the electrochemical battery performances of the graphene aerogel and xerogel show no significant difference considering their high specific capacity of about 380 mA h g-1 at 1C. Further, the surface control kinetics of the graphene aerogel are much more dominant in the supercapacitor and battery applications than those of the xerogel. This study provides more practical approaches in order to design electrodes using lightweight, high-performance, and low-cost materials for the effective use of energy storage systems.
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http://dx.doi.org/10.1039/c9nr06898hDOI Listing
October 2019

PanoView: An iterative clustering method for single-cell RNA sequencing data.

PLoS Comput Biol 2019 08 30;15(8):e1007040. Epub 2019 Aug 30.

Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America.

Single-cell RNA-sequencing (scRNA-seq) provides new opportunities to gain a mechanistic understanding of many biological processes. Current approaches for single cell clustering are often sensitive to the input parameters and have difficulty dealing with cell types with different densities. Here, we present Panoramic View (PanoView), an iterative method integrated with a novel density-based clustering, Ordering Local Maximum by Convex hull (OLMC), that uses a heuristic approach to estimate the required parameters based on the input data structures. In each iteration, PanoView will identify the most confident cell clusters and repeat the clustering with the remaining cells in a new PCA space. Without adjusting any parameter in PanoView, we demonstrated that PanoView was able to detect major and rare cell types simultaneously and outperformed other existing methods in both simulated datasets and published single-cell RNA-sequencing datasets. Finally, we conducted scRNA-Seq analysis of embryonic mouse hypothalamus, and PanoView was able to reveal known cell types and several rare cell subpopulations.
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http://dx.doi.org/10.1371/journal.pcbi.1007040DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6742414PMC
August 2019

Methimazole-Induced Pleural Effusion in the Setting of Graves' Disease.

Case Rep Endocrinol 2019 4;2019:5748938. Epub 2019 Aug 4.

Division of Endocrinology, Marshall University, Joan C. Edwards School of Medicine, USA.

Methimazole is a thionamide drug that inhibits the synthesis of thyroid hormones by blocking the oxidation of iodine in the thyroid gland. We report a case of methimazole-induced recurrent pleural effusion. A 67-year-old female with recently diagnosed Graves' disease on methimazole 20mg daily was admitted with dyspnea and new onset atrial fibrillation with rapid ventricular rate. Chest X-ray revealed a unilateral right pleural effusion, which was consistent with a transudate on thoracocentesis. She was managed as a case of congestive heart failure and methimazole dose was increased to 30 mg daily. She was readmitted twice with recurrent right pleural effusion. The fluid revealed an exudative process on repeat thoracocentesis. CT scan of the chest with contrast showed mediastinal lymphadenopathy and a diffuse ground glass process involving the right lower lobe suggestive of pneumonitis. Bronchoalveolar lavage showed neutrophil predominant fluid, and cytology and adenosine deaminase were negative. Patient also had an endobronchial ultrasound guided biopsy of the lymph nodes (EBUS). She was treated empirically with steroids 40 mg for 10 days and the methimazole was also discontinued. The antinuclear antibodies (ANA) came back positive with a speckled pattern; antineutrophil cytoplasmic antibody (c-ANCA) and antimyeloperoxidase were also positive. The effusion resolved but recurred on rechallenge with methimazole. She was referred for urgent thyroidectomy. The patient's repeat chest X-ray showed complete resolution of the pleural effusion after stopping the methimazole. Few weeks later, repeat ANCA and antimyeloperoxidase antibody were both negative. Our case report highlights the importance of the recognition of a rare side effect of methimazole. Timely diagnosis would ensure that appropriate treatment is given.
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http://dx.doi.org/10.1155/2019/5748938DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6699392PMC
August 2019

Thermoplastic Polyurethane Elastomer-Based Gel Polymer Electrolytes for Sodium-Metal Cells with Enhanced Cycling Performance.

ChemSusChem 2019 Oct 19;12(20):4645-4654. Epub 2019 Sep 19.

Department of Chemical Engineering, Hanyang University, Seoul, 04763, Republic of Korea.

Sodium batteries have been recognized as a promising alternative to lithium-ion batteries. However, the liquid electrolyte used in these batteries has inherent safety problems. Polymer electrolytes have been considered as safer and more reliable electrolyte systems for rechargeable batteries. Herein, a thermoplastic polyurethane elastomer-based gel polymer electrolyte with high ionic conductivity and high elasticity was reported. It had an ambient-temperature ionic conductivity of 1.5 mS cm and high stretchability, capable of withstanding 610 % strain. Coordination between Na ions and polymer chains increased the degree of salt dissociation in the gel polymer electrolyte compared with the liquid electrolyte. An Na/Na V (PO ) cell assembled with gel polymer electrolyte exhibited good cycling performance in terms of discharge capacity, cycling stability, and rate capability, which was owing to the effective trapping ability of organic solvents in the polymer matrix and uniform flux of sodium ions through the gel polymer electrolyte.
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http://dx.doi.org/10.1002/cssc.201901799DOI Listing
October 2019

Budget Impact of Switching to Biosimilar Trastuzumab (CT-P6) for the Treatment of Breast Cancer and Gastric Cancer in 28 European Countries.

BioDrugs 2019 Aug;33(4):423-436

College of Pharmacy, Chung-Ang University, Seoul, South Korea.

Background: As the economic burden of treating cancer patients has been soaring in European countries, performing a budget impact analysis is becoming one of the requirements for payers' application dossiers.

Objective: The objective of this study was to estimate the budgetary impact of introducing the biosimilar trastuzumab (CT-P6) from the payer's perspective and to determine the number of additional patients who could be treated with resulting savings in 28 European countries.

Methods: A budget impact model was developed to analyze the financial impact of switching from originator trastuzumab to biosimilar CT-P6 in the treatment of early and metastatic breast cancer and metastatic gastric cancer with a time horizon of 1-5 years. Budgetary savings and the number of patients potentially affected were measured based on epidemiological and sales volume data. The base-case analysis assumed that the price of CT-P6 is 70% of the originator price, the switching rate of originator to CT-P6 in the first year is 20%, and the annual growth in the switching rate for each subsequent year is 5%.

Results: For analyses using the base-case scenario following CT-P6 introduction, the total estimated budgetary savings over a 5-year period (depending on the scenario) ranged from €1.13 billion to €2.27 billion based on epidemiological data, or from €0.91 billion to €1.82 billion based on sales volume data. In the first year only, the projected budgetary savings ranged from €58 million to €136 million, and the number of additional patients who could be treated using the savings ranged from 3503 to 7078 by sensitivity analysis.

Conclusions: The conducted budget impact analysis assessing a switch from originator trastuzumab to biosimilar CT-P6 in 28 European countries indicates that budget savings could be between €0.91 billion and €2.27 billion over the next 5 years. These savings could be used to help improve patient access to local biologics in their respective countries while simultaneously strengthening the overall public health landscape across the European Union.
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http://dx.doi.org/10.1007/s40259-019-00359-0DOI Listing
August 2019

Endoscopic and microscopic findings of gastrointestinal tract in Henoch-Schönlein purpura: Single institute experience with review of literature.

Medicine (Baltimore) 2019 May;98(20):e15643

Department of Pathology, Soonchunhyang University Seoul Hospital, Seoul, Korea.

Asia has the highest incidence of Henoch-Schönlein purpura (HSP). Although 50% to 75% of patients with HSP manifest gastrointestinal (GI) symptoms, endoscopic, and pathologic findings of HSP have been rarely reviewed in Asia.Patients diagnosed with HSP who had undergone endoscopic biopsy from GI tract (GIT) in Soonchunhyang University Seoul Hospital from 2000 to 2018 were evaluated and 25 cases with 44 biopsies from upper GI tract (U-GIT) or lower GI tract (L-GIT) were enrolled. Their clinical and endoscopic findings and histologic findings of endoscopic biopsy were reviewed.Of the 25 patients, 15 were males and 10 were females. There were 6 children and 19 adults. The most common GI symptom was abdominal pain (20/25), followed by loose stool or diarrhea (9/25). Biopsied sites included 19 from U-GIT (9 stomach and 10 duodenum) and 25 from L-GIT (7 terminal ileum, 1 cecum, 4 ascending, 1 transverse, 2 descending, 7 sigmoid, and 3 rectum). Erythema/petechia was the most common endoscopic finding in U-GIT, while erosion/ulceration was the most common one in L-GIT. In U-GIT, extravasted red blood cell (RBC) (14/19) was the most common histologic finding, while leukocytoclastic vasculitis (LCV)/capillarities were identified in 7 specimens, including 5 duodenum samples. In endoscopic investigations of L-GIT, erosion/ulceration (9/14) was predominantly identified. The most common histologic finding was also extravasted RBC (22/25), while LCV/capillarities were noted in 10 specimens, including 5 specimens from terminal ileum.The HSP commonly involves GIT. Histologic findings of our cases were not significantly different from results of previous studies in Western countries. However, endoscopic and pathologic characteristics of HSP have been rarely reviewed in Asia. Herein, we share experience of endoscopic biopsy of GIT in patients with HSP.
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http://dx.doi.org/10.1097/MD.0000000000015643DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6531244PMC
May 2019

Association between statin treatment and new-onset diabetes mellitus: a population based case-control study.

Diabetol Metab Syndr 2019 22;11:30. Epub 2019 Apr 22.

2Department of Biostatistics, Catholic University College of Medicine, Seoul, Republic of Korea.

Background: Several studies suggest that statin may increase the risk of new-onset diabetes mellitus (NODM). This study aimed to evaluate the association between the duration and recent use of statin, and the risk of NODM, based on population-based data sets.

Methods: We used the South Korean National Health Insurance Service National Sample Cohort database for this nationwide case-control study. Of the 1 million participants, 6417 participants with NODM in 2012-2013 and 32,085 controls without diabetes (1:5 propensity score matched with age, sex, index year, and year of diabetes diagnosis) were included. In these patients, we examined the statin prescription record for 3 years preceding the outcome. We used conditional logistic regression to calculate the odds ratios (ORs) and 95% confidence intervals (CIs).

Results: After adjustment of covariates, there were no significant differences in the risk of NODM when analyzed according to cumulative use days. The risk of NODM was increased only in the short-term and recent user group (OR 1.48, 95% CI 1.21 to 1.82) whose cumulative prescription days are less than 6 months and whose last prescription is within 6 months of diagnosis.

Conclusions: The risk of NODM was not associated with an increase in the cumulative duration of statin use or with non-recent use. Only recent short-term use of statin was associated with an increased risk of NODM. Diabetes screening are warranted during initial statin therapy.
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http://dx.doi.org/10.1186/s13098-019-0427-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6477721PMC
April 2019

Primary cardiac angiosarcoma with right atrial wall rupture: A case report.

Medicine (Baltimore) 2019 Apr;98(14):e15020

Department of Oncology and Hematology, Soonchunhyang University Seoul Hospital, Soonchunhyang University Seoul Hospital, Soonchunhyang University College of Medicine, Seoul, Republic of Korea.

Rationale: Cardiac angiosarcoma is the most common malignant tumor of the heart and a rare disease with rapid disease progression and poor prognosis. Cardiac wall rupture is an extremely rare complication.

Patient Concerns: A 32-year-old woman presented with an acute onset of epigastric pain and chest discomfort at first time when she visited an emergency room.

Diagnoses: A cardiac mass was identified on echocardiography and subsequently performed chest computed tomography and cardiac magnetic resonance imaging revealed the cardiac tumor at right atrium with right atrial wall rupture and hematogenous lung metastasis. Histopathologic diagnosis of metastatic angiosarcoma was done by open lung biopsy.

Interventions: The patient was treated with palliative chemotherapy for the primary cardiac tumor and hematogenous lung metastasis.

Outcomes: The follow-up imaging studies revealed treatment response of the primary cardiac tumor and hematogenous lung metastasis.

Lessons: Clinical and radiologic evaluation of the cardiac angiosarcoma was well performed in our case with various diagnostic imaging modalities including echocardiography, chest computed tomography, cardiac magnetic resonance imaging, and fluorodeoxyglucose-positron emission tomography/computed tomography. This case report well demonstrates typical imaging findings of a rare cardiac tumor and emphasizes importance of early investigation for accurate diagnosis and proper management of the cardiac tumor.
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http://dx.doi.org/10.1097/MD.0000000000015020DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6456144PMC
April 2019

Tanycyte-Independent Control of Hypothalamic Leptin Signaling.

Front Neurosci 2019 19;13:240. Epub 2019 Mar 19.

Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, Baltimore, MD, United States.

Leptin is secreted by adipocytes to regulate appetite and body weight. Recent studies have reported that tanycytes actively transport circulating leptin across the brain barrier into the hypothalamus, and are required for normal levels of hypothalamic leptin signaling. However, direct evidence for leptin receptor () expression is lacking, and the effect of tanycyte-specific deletion of has not been investigated. In this study, we analyze the expression and function of the tanycytic in mice. Using single-molecule fluorescent hybridization (smfISH), RT-qPCR, single-cell RNA sequencing (scRNA-Seq), and selective deletion of the in tanycytes, we are unable to detect expression of in the tanycytes. Tanycyte-specific deletion of likewise did not affect leptin-induced pSTAT3 expression in hypothalamic neurons, regardless of whether leptin was delivered by intraperitoneal or intracerebroventricular injection. Finally, we use activity-regulated scRNA-Seq (act-Seq) to comprehensively profile leptin-induced changes in gene expression in all cell types in mediobasal hypothalamus. Clear evidence for leptin signaling is only seen in endothelial cells and subsets of neurons, although virtually all cell types show leptin-induced changes in gene expression. We thus conclude that expression in tanycytes is either absent or undetectably low, that tanycytes do not directly regulate hypothalamic leptin signaling through a -dependent mechanism, and that leptin regulates gene expression in diverse hypothalamic cell types through both direct and indirect mechanisms.
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http://dx.doi.org/10.3389/fnins.2019.00240DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6433882PMC
March 2019