Publications by authors named "Joon Ho Choi"

46 Publications

Hypoxia with inflammation and reperfusion alters membrane resistance by dynamically regulating voltage-gated potassium channels in hippocampal CA1 neurons.

Mol Brain 2021 Sep 23;14(1):147. Epub 2021 Sep 23.

Korea Brain Research Institute, 61 Cheomdan-ro, Dong-gu, Daegu, 41062, South Korea.

Hypoxia typically accompanies acute inflammatory responses in patients and animal models. However, a limited number of studies have examined the effect of hypoxia in combination with inflammation (Hypo-Inf) on neural function. We previously reported that neuronal excitability in hippocampal CA1 neurons decreased during hypoxia and greatly rebounded upon reoxygenation. We attributed this altered excitability mainly to the dynamic regulation of hyperpolarization-activated cyclic nucleotide-gated cation (HCN) channels and input resistance. However, the molecular mechanisms underlying input resistance changes by Hypo-Inf and reperfusion remained unclear. In the present study, we found that a change in the density of the delayed rectifier potassium current (I) can explain the input resistance variability. Furthermore, voltage-dependent inactivation of A-type potassium (I) channels shifted in the depolarizing direction during Hypo-Inf and reverted to normal upon reperfusion without a significant alteration in the maximum current density. Our results indicate that changes in the input resistance, and consequently excitability, caused by Hypo-Inf and reperfusion are at least partially regulated by the availability and voltage dependence of K channels. Moreover, these results suggest that selective K channel modulators can be used as potential neuroprotective drugs to minimize hypoxia- and reperfusion-induced neuronal damage.
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http://dx.doi.org/10.1186/s13041-021-00857-9DOI Listing
September 2021

Comparison of empagliflozin and sitagliptin therapy on myocardial perfusion reserve in diabetic patients with coronary artery disease.

Nucl Med Commun 2021 Sep;42(9):972-978

Department of Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.

Background: Sodium-glucose co-transporter 2 inhibitors reduce the risk of cardiovascular events in type 2 diabetic patients with coronary artery disease (CAD); however, the underlying mechanisms remain unclear.

Objectives: We compared the effects of empagliflozin vs. sitagliptin therapy on myocardial perfusion reserve (MPR) using dynamic single-photon emission computed tomography (SPECT) imaging.

Methods: In total, 100 patients with type 2 diabetes, CAD and an MPR <2.5 were randomized to receive either empagliflozin (10 mg once daily) or sitagliptin (100 mg once daily). Dynamic SPECT examinations were performed at baseline and at 6 months. The primary endpoint was the percent change of global MPR. Evaluable SPECT data were available for 98 patients.

Results: Baseline clinical characteristics and SPECT data were well balanced between the two groups. At a 6-month follow-up, the fasting glucose and glycated hemoglobin levels significantly decreased in both groups. Hematocrit and hemoglobin levels significantly increased in the empagliflozin group but not in the sitagliptin group. The global MPR significantly improved after treatment in both groups (34.5 ± 70.6%; P = 0.005 for empagliflozin vs. 22.4 ± 45.7%; P = 0.024 for sitagliptin). However, there was no significant difference in the global MPR between the two groups (P = 0.934). Similar findings were detected with regard to the regional MPR.

Conclusion: Among patients with type 2 diabetes and CAD, both empagliflozin and sitagliptin significantly improved the global MPR with no significant difference between the groups.
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http://dx.doi.org/10.1097/MNM.0000000000001429DOI Listing
September 2021

Synapses from the Motor Cortex and a High-Order Thalamic Nucleus are Spatially Clustered in Proximity to Each Other in the Distal Tuft Dendrites of Mouse Somatosensory Cortex.

Cereb Cortex 2021 Aug 5. Epub 2021 Aug 5.

Laboratory of Neurophysiology, Korea Brain Research Institute, Daegu 41067, Republic of Korea.

The posterior medial nucleus of the thalamus (POm) and vibrissal primary motor cortex (vM1) convey essential information to the barrel cortex (S1BF) regarding whisker position and movement. Therefore, understanding the relative spatial relationship of these two inputs is a critical prerequisite for acquiring insights into how S1BF synthesizes information to interpret the location of an object. Using array tomography, we identified the locations of synapses from vM1 and POm on distal tuft dendrites of L5 pyramidal neurons where the two inputs are combined. Synapses from vM1 and POm did not show a significant branchlet preference and impinged on the same set of dendritic branchlets. Within dendritic branches, on the other hand, the two inputs formed robust spatial clusters of their own type. Furthermore, we also observed POm clusters in proximity to vM1 clusters. This work constitutes the first detailed description of the relative distribution of synapses from POm and vM1, which is crucial to elucidate the synaptic integration of whisker-based sensory information.
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http://dx.doi.org/10.1093/cercor/bhab236DOI Listing
August 2021

Instant, multiscale dry transfer printing by atomic diffusion control at heterogeneous interfaces.

Sci Adv 2021 Jul 9;7(28). Epub 2021 Jul 9.

Department of Robotics Engineering, Daegu Gyeongbuk Institute of Science and Technology, Daegu 42988, South Korea.

Transfer printing is a technique that integrates heterogeneous materials by readily retrieving functional elements from a grown substrate and subsequently printing them onto a specific target site. These strategies are broadly exploited to construct heterogeneously integrated electronic devices. A typical wet transfer printing method exhibits limitations related to unwanted displacement and shape distortion of the device due to uncontrollable fluid movement and slow chemical diffusion. In this study, a dry transfer printing technique that allows reliable and instant release of devices by exploiting the thermal expansion mismatch between adjacent materials is demonstrated, and computational studies are conducted to investigate the fundamental mechanisms of the dry transfer printing process. Extensive exemplary demonstrations of multiscale, sequential wet-dry, circuit-level, and biological topography-based transfer printing demonstrate the potential of this technique for many other emerging applications in modern electronics that have not been achieved through conventional wet transfer printing over the past few decades.
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http://dx.doi.org/10.1126/sciadv.abh0040DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8270493PMC
July 2021

Occurrence of Leaf Spot of Caused by in China.

Plant Dis 2021 May 24. Epub 2021 May 24.

Wonkwang University, 35030, Department of Food Science and Biotechnology, Iksan, Jeollabuk-do, Korea (the Republic of).

Oats () are an important fodder crop in the vast ranges of northern and northwestern China, given the growing demand from livestock. (Yang et al. 2010). In July 2020, diseased leaf samples of cultivar Dingyan-2 were collected from fields near Gonghui Town, Zhangbei County, Zhangjiakou City (41.35° N, 114.55° E). These leaves showed oval to irregular yellowish-brown spots (0.5 to 6 mm in diameter) surrounded by a yellowish halo progressing to form narrowly striped spots fusing into lesions in severe cases. In a disease survey of six fields (about 1.5 ha in total), 35% of the plants were infected with a disease severity ranging from 0 to 20%. To isolate the pathogen, 12 symptomatic leaves (two leaves for each plant) were arbitrarily sampled from different locations across the fields and small pieces (5 mm) of diseased leaves were excised from the border between diseased and healthy tissue. Excised tissue pieces were surface sterilized by immersion in 75 % ethanol for 30 s, then 1% NaClO solution for 1 min, rinsed in sterilized distilled water three times, and transferred to potato dextrose agar (PDA). Colonies on PDA were 41-46 mm diam in 10 d at 25 °C with surface texture floccose, obverse pale mouse grey to black due to ascomata and aerial mycelium, and reverse pale olivaceous. Asci were ellipsoidal to ovoid, 12-18 × 11-15 μm (av.= 15 ×12 μm; n=30) in spore-bearing part, containing eight irregularly arranged ascospores. Ascospores were 1-celled, dark brown when mature, smooth, ellipsoidal, with attenuated ends, 7.5-8.4 × 4.3-5.5 μm (av.= 8.1 × 5.0 μm; =50), with an apical or slightly subapical germ pore. These morphological characteristics were consistent with previous descriptions of (syn. , Wang et al. 2019). For molecular identification, genomic DNA (isolate MNK-Y1) was extracted and the internal transcribed spacer (ITS) region and β-tubulin () were amplified and sequenced by using the primers ITS1 and ITS4 (White et al. 1990) and Btub2Fd and Btub4Rd (Woudenberg et al. 2009). Sequences were deposited in GenBank under accessions MW080329 (ITS) and MW557539 (tub2). Blast search revealed that the ITS and tub2 sequences matched 99.4%, 100% (471 bp out of 474 bp; 648 bp out of 648 bp) with the sequences of the ex-type isolate CBS 276.74 of C. microsporus accession number MH860852.1 and MK926899. Koch's postulates were proven to confirm the pathogenicity of isolate MNK-Y1. Eight-week-old healthy oat seedlings of cv. Dingyan 2 were grown in the greenhouse, at 15-20 ℃ under 30-40% of relative humidity. Ten oat plants were spray inoculated with a spore suspension (5×10spores/ml; isolate MNK-Y1). Another ten oat plants were sprayed with sterile water as controls. All plants were covered with a transparent glass cover and a black polyethylene bag to maintain relative humidity and dark for two days. After 15 days, all the inoculated plants had developed yellowish-brown spots similar to those observed in the field whereas the control plants sprayed with sterile water remained healthy. The pathogen was reisolated from inoculated plants and identified as based on morphological characteristics and the molecular methods described above. This species has previously been isolated from saline and desert soils as well as from leaves of (Wang et al. 2019). To our knowledge, this is the first report of leaf spot of oat caused by in China.
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http://dx.doi.org/10.1094/PDIS-11-20-2346-PDNDOI Listing
May 2021

Injection of contrast media using a large-bore angiography catheter with a guidewire in place: Physical factors influencing injection pressure in cerebral angiography.

Interv Neuroradiol 2021 Aug 13;27(4):558-565. Epub 2020 Dec 13.

Department of Radiology, Research Institute of Radiology, 65526Asan Medical Center, 37994University of Ulsan College of Medicine, Seoul, Republic of Korea.

Background: We have used a contrast injection scheme termed as "guided catheterization method (guided method)." By using a large-bore 5-Fr catheter and 0.032-in guidewire, a contrast medium could be injected without removing the guidewire. Using a neurovascular phantom, we studied the influence of leaving the guidewire on the contrast injection pressure. Image quality was compared with that obtained using a 4-Fr regular angiography catheter (conventional method).

Methods: Actual contrast injection pressure, flow rate, flow volume, and several variables from the time-density curve (TDC) were obtained using the guided method and the conventional method. Catheterization parameters included flow rate, the viscosity of a contrast medium (CM), and catheter length. The pressure limit of a contrast injector was set as 1200 psi. Digital subtraction angiography (DSA) images on the neurovascular phantom were acquired. The DSA images were processed, and TDC on a specific region of interest was obtained. Variables from TDC were calculated and compared between the different catheters.

Results: The ranges of actual contrast injection pressure with the conventional and the guided method were 138-299 psi and 184-451 psi, respectively. A minimal reduction of the actual flow rate was found under some conditions with the guided method. Comparable opacifications in DSA images were achieved in all conditions. Although peak intensity was different by flow rate or CM, all TDC variables did not differ based on the catheter. There were no significant harmful events during the 90 experiments.

Conclusions: With adjustment of the pressure limit, cerebral angiography using the 5-Fr, large-bore catheter without removal of the guidewire is feasible, safe, and expected to provide image quality comparable to that of the 4-Fr regular catheter.
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http://dx.doi.org/10.1177/1591019920980876DOI Listing
August 2021

Early prediction of neoadjuvant chemotherapy response for advanced breast cancer using PET/MRI image deep learning.

Sci Rep 2020 12 3;10(1):21149. Epub 2020 Dec 3.

Department of Nuclear Medicine, Korea Cancer Center Hospital, Korea Institute of Radiological and Medical Sciences (KIRAMS), Seoul, Republic of Korea.

This study aimed to investigate the predictive efficacy of positron emission tomography/computed tomography (PET/CT) and magnetic resonance imaging (MRI) for the pathological response of advanced breast cancer to neoadjuvant chemotherapy (NAC). The breast PET/MRI image deep learning model was introduced and compared with the conventional methods. PET/CT and MRI parameters were evaluated before and after the first NAC cycle in patients with advanced breast cancer [n = 56; all women; median age, 49 (range 26-66) years]. The maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) were obtained with the corresponding baseline values (SUV0, MTV0, and TLG0, respectively) and interim PET images (SUV1, MTV1, and TLG1, respectively). Mean apparent diffusion coefficients were obtained from baseline and interim diffusion MR images (ADC0 and ADC1, respectively). The differences between the baseline and interim parameters were measured (ΔSUV, ΔMTV, ΔTLG, and ΔADC). Subgroup analysis was performed for the HER2-negative and triple-negative groups. Datasets for convolutional neural network (CNN), assigned as training (80%) and test datasets (20%), were cropped from the baseline (PET0, MRI0) and interim (PET1, MRI1) images. Histopathologic responses were assessed using the Miller and Payne system, after three cycles of chemotherapy. Receiver operating characteristic curve analysis was used to assess the performance of the differentiating responders and non-responders. There were six responders (11%) and 50 non-responders (89%). The area under the curve (AUC) was the highest for ΔSUV at 0.805 (95% CI 0.677-0.899). The AUC was the highest for ΔSUV at 0.879 (95% CI 0.722-0.965) for the HER2-negative subtype. AUC improved following CNN application (SUV0:PET0 = 0.652:0.886, SUV1:PET1 = 0.687:0.980, and ADC1:MRI1 = 0.537:0.701), except for ADC0 (ADC0:MRI0 = 0.703:0.602). PET/MRI image deep learning model can predict pathological responses to NAC in patients with advanced breast cancer.
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http://dx.doi.org/10.1038/s41598-020-77875-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7712787PMC
December 2020

Comprehensive Analysis of Long-Range Connectivity from and to the Posterior Parietal Cortex of the Mouse.

Cereb Cortex 2021 01;31(1):356-378

Laboratory of Neurophysiology, Korea Brain Research Institute, Daegu 41062, Korea.

The posterior parietal cortex (PPC) is a major multimodal association cortex implicated in a variety of higher order cognitive functions, such as visuospatial perception, spatial attention, categorization, and decision-making. The PPC is known to receive inputs from a collection of sensory cortices as well as various subcortical areas and integrate those inputs to facilitate the execution of functions that require diverse information. Although many recent works have been performed with the mouse as a model system, a comprehensive understanding of long-range connectivity of the mouse PPC is scarce, preventing integrative interpretation of the rapidly accumulating functional data. In this study, we conducted a detailed neuroanatomic and bioinformatic analysis of the Allen Mouse Brain Connectivity Atlas data to summarize afferent and efferent connections to/from the PPC. Then, we analyzed variability between subregions of the PPC, functional/anatomical modalities, and species, and summarized the organizational principle of the mouse PPC. Finally, we confirmed key results by using additional neurotracers. A comprehensive survey of the connectivity will provide an important future reference to comprehend the function of the PPC and allow effective paths forward to various studies using mice as a model system.
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http://dx.doi.org/10.1093/cercor/bhaa230DOI Listing
January 2021

Korean Medication Algorithm for Schizophrenia 2019, Second Revision: Treatment of Psychotic Symptoms.

Clin Psychopharmacol Neurosci 2020 08;18(3):386-394

Institute of Behavioral Science in Medicine and Department of Psychiatry, Yonsei University College of Medicine, Seoul, Korea.

Objective: In 2001, the Korean College of Neuropsychopharmacology and the Korean Society for Schizophrenia Research developed the Korean Medication Algorithm Project for Schizophrenia (KMAP-SPR 2001, revised 2006) through a consensus of expert opinion. The present study was carried out to support the second revision of the KMAP-SPR.

Methods: Based on clinical guidelines and studies on the treatment of psychotic symptoms in schizophrenia, the Executive committee completed a draft of KMAP-SPR 2019. To obtain an expert consensus, a Review committee of 100 Korean psychiatrists was formed and 69 responded to a 30-item questionnaire. Based on their responses, the KMAP-SPR 2019 was finalized.

Results: The revised schizophrenia algorithm now consists of 5 stages. At Stage 1, monotherapy with atypical antipsychotics was recommended by expert reviewers as the first-line strategy. At Stage 2, most reviewers recommended the use of typical or atypical antipsychotic drugs not used at Stage 1. At Stage 3, many reviewers agreed with the administration of clozapine. At Stage 4, a combination of clozapine and other agents such as antipsychotics, mood stabilizers, antidepressants, or electroconvulsive therapy was recommended. At Stage 5, most reviewers recommended combined treatment with an antipsychotic other than clozapine; and a mood stabilizer, antidepressant, or electroconvulsive therapy. At any stage, prescribing long-acting injectable antipsychotics at the discretion of the clinician was recommended.

Conclusion: Compared with previous versions, the KMAP-SPR 2019 now recommends using clozapine earlier in treatment- refractory schizophrenia. In addition, the use of long-acting injectable antipsychotics is now considered to be available at any stage.
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http://dx.doi.org/10.9758/cpn.2020.18.3.386DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7383009PMC
August 2020

Frequency-dependent gating of feedforward inhibition in thalamofrontal synapses.

Mol Brain 2020 05 6;13(1):68. Epub 2020 May 6.

Korea Brain Research Institute, 61 Cheomdan-ro, Daegu, 41062, Republic of Korea.

Thalamic recruitment of feedforward inhibition is known to enhance the fidelity of the receptive field by limiting the temporal window during which cortical neurons integrate excitatory inputs. Feedforward inhibition driven by the mediodorsal nucleus of the thalamus (MD) has been previously observed, but its physiological function and regulation remain unknown. Accumulating evidence suggests that elevated neuronal activity in the prefrontal cortex is required for the short-term storage of information. Furthermore, the elevated neuronal activity is supported by the reciprocal connectivity between the MD and the medial prefrontal cortex (mPFC). Therefore, detailed knowledge about the synaptic connections during high-frequency activity is critical for understanding the mechanism of short-term memory. In this study, we examined how feedforward inhibition of thalamofrontal connectivity is modulated by activity frequency. We observed greater short-term synaptic depression during disynaptic inhibition than in thalamic excitatory synapses during high-frequency activities. The strength of feedforward inhibition became weaker as the stimulation continued, which, in turn, enhanced the range of firing jitter in a frequency-dependent manner. We postulated that this phenomenon was primarily due to the increased failure rate of evoking action potentials in parvalbumin-expressing inhibitory neurons. These findings suggest that the MD-mPFC pathway is dynamically regulated by an excitatory-inhibitory balance in an activity-dependent manner. During low-frequency activities, excessive excitations are inhibited, and firing is restricted to a limited temporal range by the strong feedforward inhibition. However, during high-frequency activities, such as during short-term memory, the activity can be transferred in a broader temporal range due to the decreased feedforward inhibition.
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http://dx.doi.org/10.1186/s13041-020-00608-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7201790PMC
May 2020

Safety and Effectiveness of Percutaneous Low-Dose Thrombin Injection for Femoral Puncture Site Pseudoaneurysms in Neurointervention: Single-Center Experience.

Neurointervention 2020 Mar 2;15(1):25-30. Epub 2020 Jan 2.

Department of Radiology, Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.

Purpose: We present ultrasound-guided percutaneous low-dose thrombin (200-250 IU) injection for the treatment of iatrogenic femoral pseudoaneurysms. Second, we compared patient and procedure factors between subcutaneous hematoma and pseudoaneurysm groups.

Materials And Methods: From April 2012 to May 2018, 8425 patients underwent neurointervention. Among these patients, 18 had small subcutaneous hematomas and 6 had pseudoaneurysms. Pseudoaneurysms in the neck and entire sac were visualized, and low-dose thrombins were injected while visualizing a "whirlpool" hyperechoic core in the pseudoaneurysm sac. Subcutaneous hematomas were treated with simple compression. We compared the following parameters between the subcutaneous hematoma group and pseudoaneurysm group: sex, age, body mass index (BMI), type of procedure, heparin usage, sheath size, procedure time, and number of previous neurointervention procedures with the Mann-Whitney U test.

Results: Most of the pseudoaneurysms were successfully occluded with 200 IU of thrombin (n=5). Only 1 pseudoaneurysm required a slightly higher thrombin concentration (250 IU, n=1). During the short-term follow-up, no residual sac was observed and no surgical repair was necessary. Pain in the groin region was alleviated. During the 1-month follow-up, no evidence of pseudoaneurysm recurrence nor subcutaneous hematoma was noted. Patient factors (sex, age, and BMI) and procedure factors (heparin usage, sheath size, procedure time, number of previous procedures) were not statistically different between the subcutaneous hematoma and pseudoaneurysm groups.

Conclusion: Ultrasound-guided percutaneous low-dose thrombin injection (200-250 IU) is safe, effective, and less invasive for treating iatrogenic femoral pseudoaneurysm in neurointervention.
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http://dx.doi.org/10.5469/neuroint.2019.00206DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7105095PMC
March 2020

The Scales Project, a cross-national dataset on the interpretation of thermal perception scales.

Sci Data 2019 11 26;6(1):289. Epub 2019 Nov 26.

Department of Mechanical Engineering, Eindhoven University of Technology, Groene Loper 3, 5612AE, Eindhoven, The Netherlands.

Thermal discomfort is one of the main triggers for occupants' interactions with components of the built environment such as adjustments of thermostats and/or opening windows and strongly related to the energy use in buildings. Understanding causes for thermal (dis-)comfort is crucial for design and operation of any type of building. The assessment of human thermal perception through rating scales, for example in post-occupancy studies, has been applied for several decades; however, long-existing assumptions related to these rating scales had been questioned by several researchers. The aim of this study was to gain deeper knowledge on contextual influences on the interpretation of thermal perception scales and their verbal anchors by survey participants. A questionnaire was designed and consequently applied in 21 language versions. These surveys were conducted in 57 cities in 30 countries resulting in a dataset containing responses from 8225 participants. The database offers potential for further analysis in the areas of building design and operation, psycho-physical relationships between human perception and the built environment, and linguistic analyses.
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http://dx.doi.org/10.1038/s41597-019-0272-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6879730PMC
November 2019

Estimated radiation dose according to the craniocaudal angle in cerebral digital subtraction angiography: Patient and phantom study.

J Neuroradiol 2019 Nov 16;46(6):345-350. Epub 2019 Jul 16.

Department of Radiology, Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, 88, Olympic-ro 43-gil, Songpa-gu, Seoul 05505, Korea. Electronic address:

Background And Purpose: Routine use of cranial angulation with 15-20 degrees, craniocaudal angled (CC) view, for cerebral digital subtraction angiography (DSA) helps minimize bone subtraction artifacts with less overlapping of the vessels, however, it may increase the radiation dose. We designed the phantom and patient studies to determine the effect of the angulation to the radiation dose and the feasibility of true posteroanterior angled (PA) view, in cerebral DSA.

Materials And Methods: In the phantom study, frontal DSA was simulated with variable angulations. In the patient study with thirty-one subjects, one internal carotid arteriogram was obtained with the CC view and the other, PA view in every patient. The dose-area product (DAP) and reference air-kerma (AK) were measured and compared between the angles. A qualitative analysis was performed to assess the diagnostic performance of the DSA over the angles.

Results: The phantom study confirmed that the greater craniocaudal angles caused higher radiation exposure. Especially, the radiation dose (AK) of the CC view was 5.4% higher than that of the PA view. In the patient study, the radiation dose of the PA view was significantly lower compared to the CC view (1.44 vs. 1.63 mGy, AK). In 4 patients, the dose particularly jumped when applying the CC view as the copper filter was automatically removed. The diagnostic ability of the DSA with the PA view tended to be higher without significance.

Conclusions: In a daily routine cerebral angiography, a simple modification of the angle may help to minimize the radiation dose.
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http://dx.doi.org/10.1016/j.neurad.2019.07.003DOI Listing
November 2019

Efficiency of Air Bubble Removal in Preparation of Low-Profile Angioplasty Balloon Catheter: Bench-Top Comparison of Six Methods.

Neurointervention 2019 Mar 8;14(1):27-34. Epub 2019 Jan 8.

Department of Radiology, Research Institute of Radiology, Asan Medical Center, Seoul, Korea.

Purpose: Complete removal of air bubbles from balloons for neurovascular angioplasty is cumbersome. We compared the preparation difficulty, air removal efficiency, and air collection pattern of six different balloon catheter preparation methods to propose a better preparation method for both initial and second balloon uses, especially for small-profile angioplasty balloon catheters.

Materials And Methods: A total of 18 neurovascular angioplasty balloon catheters with nominal diameters of 2 mm were prepared to test six different preparation methods: the instruction for use method (method A), simplified method using a syringe (method B) and four newly devised preparation methods using inflating devices (methods C-F). Serial radiographs were obtained while the balloons were gradually inflated. We measured the time for each preparation and the bubble number, analyzed their distribution in the balloon, and calculated the contrast filling ratio (contrast filling area/total balloon area) for initial and second ballooning. The whole process was repeated three times.

Results: The preparation time varied widely (11.5 seconds [method D] to 73.3 seconds [method A]). On initial inflation, the contrast filling ratio at 8 atm was the highest (100%) with methods A and F. On second inflation, the ratio was again highest with method A (99.5%), followed by method F (99.2%). Initial ballooning tended to show a uniform pattern of single bubble in the distal segment of the balloon; in contrast, second ballooning showed varying patterns in which the bubbles were multiple and randomly distributed.

Conclusion: None of the six methods were able to completely exclude air bubbles from the balloon catheters including the second ballooning; however, the method of repeating aspiration with high-volume inflating device (method F) could be a practical option considering the simplicity and efficiency of preparation.
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http://dx.doi.org/10.5469/neuroint.2018.01074DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6433189PMC
March 2019

An enhanced treatment effect can be expected from a higher serum thyroglobulin level after radioactive iodine therapy.

Ann Nucl Med 2019 Feb 31;33(2):128-134. Epub 2018 Oct 31.

Department of Nuclear Medicine, Korea Cancer Center Hospital, Korea Institute of Radiological and Medical Sciences (KIRAMS), 75, Nowon-ro, Nowon-gu, Seoul, 139-706, Republic of Korea.

Objective: The aim of this study was to investigate if increased serum thyroglobulin (Tg) levels after radioactive iodine (RAI) showed more therapeutic effects in patients with differentiated thyroid cancer (DTC).

Methods: Data of 65 patients with DTC who underwent RAI from June 2014 to September 2016 were reviewed. Serum thyroglobulin was measured immediately before (Tg1) and 48 h (Tg2) after RAI under TSH stimulation. Differences and ratios between serum Tg measurements (DeltaTg = Tg2 - Tg1 and RatioTg = Tg2/Tg1) were calculated. The treatment response of distant metastasis was assessed using the RECIST criteria.

Results: There was no difference in the median values of Tg1 and Tg2 (2.6 [range, 0.7-1957.5] ng/mL vs. 7.4 [range, 0.7-5276.0] ng/mL, p = 0.240) in all patients (73 scans, 65 patients). In subgroup analysis, Tg levels increased slightly in patients with distant metastasis (8 scans, 7 patients) (Tg1 vs. Tg2; 48.9 [range, 2.4-1957.5] ng/mL vs. 63.2 [range, 4.4-5276.0] ng/mL, p = 0.408). Among patients with distant metastasis, one patient with a partial response to treatment had a more than 4000fold increase in Tg levels and one patient with stable disease showed a 20fold increase in Tg levels. In contrast, five patients with disease progression showed only two to eightfold increase or more than 100fold decrease in Tg levels at 48 h after RAI. However, there was a significant increase in serum Tg levels in patients without distant metastasis (65 scans, 58 patients) after RAI (Tg1 vs. Tg2; 2.0 [range, 0.7-141.9] ng/mL vs. 6.8 [range, 0.7-577.7] ng/mL, p = 0.026).

Conclusions: A higher elevation of Tg levels after RAI may be associated with a better treatment outcome in DTC patients with distant metastasis. An increase in Tg levels after RAI may reflect the destruction of cancer and thyroid cells.
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http://dx.doi.org/10.1007/s12149-018-1313-5DOI Listing
February 2019

Prediction of tumor differentiation using sequential PET/CT and MRI in patients with breast cancer.

Ann Nucl Med 2018 Jul 23;32(6):389-397. Epub 2018 May 23.

Department of Nuclear Medicine, Korea Cancer Center Hospital, Korea Institute of Radiological and Medical Sciences (KIRAMS), Seoul, Republic of Korea.

Objective: The aim of this study is to assess tumor differentiation using parameters from sequential positron emission tomography/computed tomography (PET/CT) and magnetic resonance imaging (MRI) in patients with breast cancer.

Methods: This retrospective study included 78 patients with breast cancer. All patients underwent sequential PET/CT and MRI. For fluorodeoxyglucose (FDG)-PET image analysis, the maximum standardized uptake value (SUV) of FDG was assessed at both 1 and 2 h and metabolic tumor volume (MTV) and total lesion glycolysis (TLG). The kinetic analysis of dynamic contrast-enhanced MRI parameters was performed using dynamic enhancement curves. We assessed diffusion-weighted imaging (DWI)-MRI parameters regarding apparent diffusion coefficient (ADC) values. Histologic grades 1 and 2 were classified as low-grade, and grade 3 as high-grade tumor.

Results: Forty-five lesions of 78 patients were classified as histologic grade 3, while 26 and 7 lesions were grade 2 and grade 1, respectively. Patients with high-grade tumors showed significantly lower ADC-mean values than patients with low-grade tumors (0.99 ± 0.19 vs.1.12 ± 0.32, p = 0.007). With respect to SUV1, MTV2.5, and TLG2.5, patients with high-grade tumors showed higher values than patients with low-grade tumors: SUV1 (7.92 ± 4.5 vs.6.19 ± 3.05, p = 0.099), MTV2.5 (7.90 ± 9.32 vs.4.38 ± 5.10, p = 0.095), and TLG2.5 (40.83 ± 59.17 vs.19.66 ± 26.08, p = 0.082). However, other parameters did not reveal significant differences between low-grade and high-grade malignancies. In receiver-operating characteristic (ROC) curve analysis, ADC-mean values showed the highest area under the curve of 0.681 (95%CI 0.566-0.782) for assessing high-grade malignancy.

Conclusions: Lower ADC-mean values may predict the poor differentiation of breast cancer among diverse PET-MRI functional parameters.
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http://dx.doi.org/10.1007/s12149-018-1259-7DOI Listing
July 2018

Synaptic transmission and excitability during hypoxia with inflammation and reoxygenation in hippocampal CA1 neurons.

Neuropharmacology 2018 08 26;138:20-31. Epub 2018 May 26.

Korea Brain Research Institute, 61 Cheomdan-ro, Dong-gu, Daegu, 41068, South Korea; Daegu Gyeongbuk Institute of Science and Technology, 333 Techno Jungang-daero, Hyeonpung-myeon, Dalseong-gun, Daegu, 42988, South Korea. Electronic address:

Although a number of experimental and clinical studies have shown that hypoxia typically accompanies acute inflammatory responses, the combinatorial effect of the two insults on basic neural function has not been thoroughly investigated. Previous studies have predominantly suggested that hypoxia reduces network activity; however, several studies suggest the opposite effect. Of note, inflammation is known to increase neural activity. In the current study, we examined the effects of limited oxygen in combination with an inflammatory stimulus, as well as the effects of reoxygenation, on synaptic transmission and excitability. We observed a significant reduction of both synaptic transmission and excitability when hypoxia and inflammation occurred in combination, whereas reoxygenation caused hyperexcitability of neurons. Further, we found that the observed reduction in synaptic transmission was due to compromised presynaptic release efficiency based on an adenosine-receptor-dependent increase in synaptic facilitation. Excitability changes in both directions were attributable to dynamic regulation of the hyperpolarization-activated cation current (I) and to changes in the input resistance and the voltage difference between resting membrane potential and action potential threshold. We found that zatebradine, an I current inhibitor, reduced the fluctuation in excitability, suggesting that it may have potential as a drug to ameliorate reperfusion brain injury.
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http://dx.doi.org/10.1016/j.neuropharm.2018.05.011DOI Listing
August 2018

The Predictive Values of Lesion Size, F-18 FDG Avidity and I-131 Avidity for the Clinical Outcome of I-131 Treatment in Patients with Metastatic Differentiated Thyroid Carcinoma Only in the Lung.

Nucl Med Mol Imaging 2018 Apr 7;52(2):135-143. Epub 2017 Nov 7.

Department of Nuclear Medicine, Korea Cancer Center Hospital, Korea Institute of Radiological and Medical Sciences (KIRAMS), 75, Nowon-ro, Nowon-gu, Seoul, 139-706 Republic of Korea.

Purpose: We aimed to evaluate the prognostic values of radiography, F-18 FDG PET, and I-131 whole body scans in patients with lung-only metastasis from differentiated thyroid carcinoma (DTC).

Methods: Between 1998 and 2013, we included 31 patients (F: 26, M: 5) with lung-only metastasis from DTC who had been treated with I-131 and underwent PET. Lung metastasis was categorized according to the size (macronodular ≥1.0 cm vs. micronodular <1.0 cm), FDG avidity (avid vs. non-avid), and I-131 avidity (avid vs. non-avid). Progression-free survival (PFS) was evaluated for each patient.

Results: Among 31 patients, seven (23%) had macronodular lung metastasis, 26 (84%) had FDG avid lung metastasis, and 16 (52%) had I-131 avid lung metastasis. During the median follow-up period of 9.4 y, median PFS was 6.1 y. Based on Kaplan-Meier analysis, macronodular lung metastasis ( = 0.017) and I-131 non-avid lung metastasis ( = 0.059) were significantly associated with worse outcomes, but FDG avid lung metastasis was not ( = 0.135). Patients with FDG non-avid lung metastasis did not experience disease progression during follow-up, while 11 of 26 patients (42%) experienced disease progression. Based on univariate analysis, the hazard ratio for a poor prognosis was 3.78 ( = 0.029) for macronodular lung metastasis and 3.29 ( = 0.079) for I-131 non-avid lung metastasis.

Conclusions: Macronodular and I-131 non-avid lung metastasis were associated with a poor prognosis in lung-only metastasis from DTC. Although FDG avid lung metastasis may be associated with a poor prognosis, a larger-scale study is needed.
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http://dx.doi.org/10.1007/s13139-017-0502-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5897259PMC
April 2018

Head-to-head comparison of F-FP-CIT and I-FP-CIT for dopamine transporter imaging in patients with Parkinson's disease: A preliminary study.

Synapse 2018 07 9;72(7):e22032. Epub 2018 Mar 9.

Department of Nuclear Medicine, Korea Cancer Center Hospital, Korea Institutes of Radiological and Medical Sciences, Seoul, Korea.

I-FP-CIT and F-FP-CIT are radiotracers which are widely used to diagnose Parkinson's disease (PD). However, to our knowledge, no studies to date have made head-to-head comparisons between I-FP-CIT and F-FP-CIT. Therefore, in this study, I-FP-CIT SPECT/CT was compared with F-FP-CIT PET/CT in the same cohort of subjects. Patients with PD and essential tremor (ET) underwent I-FP-CIT SPECT/CT and F-FP-CIT PET/CT. Visual and semiquantitative analyses were conducted. The specific binding ratio (SBR) and putamen to caudate ratio (PCR) were compared between subjects who underwent I-FP-CIT SPECT/CT and F-FP-CIT PET/CT. Visual analysis showed that the striatal uptake of both radiotracers was decreased in the PD group, whereas striatal uptake was intact in the ET group. The SBR between I-FP-CIT SPECT/CT and F-FP-CIT PET/CT showed a positive correlation (r = .78, p < .01). However, the mean SBRs on F-FP-CIT PET/CT were higher than those on I-FP-CIT SPECT/CT (2.19 ± .87 and 1.22 ± .49, respectively; p < .01). The PCRs in these two modalities were correlated with each other (r = .71, p < .01). The mean PCRs on F-FP-CIT PET/CT were not significantly higher than those on I-FP-CIT SPECT/CT (1.31 ± .19 and 0.98 ± .06, respectively; p = .06). These preliminary results indicate that the uptake of both I-FP-CIT and F-FP-CIT was decreased in the PD group when compared with the ET controls. Visual analyses using both methods did not affect the diagnostic accuracy in this study. However, semiquantitative analysis indicated a better contrast of F-FP-CIT PET/CT relative to I-FP-CIT SPECT/CT.
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http://dx.doi.org/10.1002/syn.22032DOI Listing
July 2018

Optimal Guiding Catheter Length for Endovascular Coiling of Intracranial Aneurysms in Anterior Circulation in Era of Flourishing Distal Access System.

Neurointervention 2017 Sep 5;12(2):91-99. Epub 2017 Sep 5.

Department of Radiology and Research Institute of Radiology, Asan Medical Center, Seoul, Korea.

Purpose: To determine the minimum required guiding catheter length for embolization of various intracranial aneurysms in anterior circulation and to analyze the effect of various patient factors on the required catheter length and potential interaction with its stability.

Materials And Methods: From December 2016 to March 2017, 90 patients with 93 anterior circulation aneurysms were enrolled. Three types of guiding catheters (Envoy, Envoy DA, and Envoy DA XB; Codman Neurovascular, Raynham, MA, USA) were used. We measured the in-the-body length of the catheter and checked the catheter tip location in the carotid artery. We analyzed factors affecting the in-the-body length and stability of the guiding catheter system.

Results: The average (±standard deviation) in-the-body length of the catheter was 84.2±5.9 cm. The length was significantly longer in men (89.1±5.6 vs. 82.1±4.6 cm, P<0.001), patients older than 65 years (87.7±7.8 vs. 82.7±4.2 cm, P<0.001), patients with a more tortuous arch (arch type 2 and 3) (87.5±7.4 vs. 82.7±4.4 cm, P<0.001), and patients with a distal aneurysm location (distal group) (86.2±5.0 vs. 82.7±6.1 cm, P=0.004). A shift in the tip location was noted in 19 patients (20.4%); there was no significant different among the 3 catheters (P=0.942).

Conclusion: The minimum required length of a guiding catheter was 84 cm on average for elective anterior-circulation aneurysm embolization. The length increased in men older than 65 years with a more tortuous arch. We could reach a higher position with distal access catheters with little difference in the stability once we reached the target location.
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http://dx.doi.org/10.5469/neuroint.2017.12.2.91DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5613050PMC
September 2017

The Incidence and Characteristics of Patients with Small Ruptured Aneurysms (<5 mm) in Subarachnoid Hemorrhage.

J Korean Neurosurg Soc 2017 Jul 31;60(4):424-432. Epub 2017 Jul 31.

Department of Neurosurgery, Busan-Ulsan Regional Cardio-Cerebrovascular Center, Medical Science Research Center, College of Medicine, Dong-A University, Busan, Korea.

Objective: Small unruptured aneurysms (<5 mm) are known for their very low risk of rupture, and are recommended to be treated conservatively. However, we encounter many patients with small ruptured aneurysms in the clinical practice. We aimed to investigate the incidence and characteristics of patients with small ruptured aneurysms.

Methods: We reviewed all patients admitted to our hospital with subarachnoid hemorrhage from January 2005 to December 2015. The patients were divided into two groups: those with aneurysms <5 mm (group S) and those with aneurysms ≥5 mm (group L). The patient's age and sex, size and location of aneurysms, and risk factors such as hypertension, diabetes, alcohol use, and smoking were compared between the two groups.

Results: Eight-hundred eleven patients were diagnosed with ruptured aneurysms, and 337 (41.6%) were included in group S. The mean size of all aneurysms was 6.10±2.99 mm (range, 0.7-37.7); aneurysms with a diameter of 4-5 mm accounted for the largest subgroup of all aneurysms. Female sex was significantly associated with the incidence of small ruptured aneurysms (odds ratio [OR] 1.50, 95% confidence intervals [CI] 1.02-2.19, =0.037). Despite female predominance in the incidence of small ruptured aneurysms, the proportion of small ruptured aneurysms in young (<50 years) men was high. In men, there were no significant differences regarding the location of the aneurysms between group S and group L (=0.267), with the most frequent location being the anterior communicating artery (ACoA) in both group S (50.9%) and group L (51.4%). However, in women, there were significant differences regarding the location of the aneurysms between group S and group L (=0.023), with the most frequent locations being the ACoA (33.0%) in group S, and the posterior communicating artery (30.6%) in group L. In women, two locations were significantly associated with small (<5 mm) ruptured aneurysms: the ACoA (OR 2.14, 95% CI 1.01-4.54, =0.047) and anterior cerebral artery (OR 3.54, 95% CI 1.19-10.54, =0.023). Multiplicity and smoking were significantly associated with large (≥5 mm) ruptured aneurysms in women. The use of alcohol was related to small ruptured aneurysms in men over 50 years of age (OR 2.23, 95% CI 1.03-4.84, =0.042).

Conclusion: In this study, small (<5 mm) ruptured aneurysms exhibited different incidences by age, sex, location, and risk factors such as multiplicity, smoking, and alcohol use.
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http://dx.doi.org/10.3340/jkns.2016.0910.003DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5544372PMC
July 2017

Treatment Strategy for Isolated Posterior Inferior Cerebellar Artery Dissection.

World Neurosurg 2017 Feb 24;98:644-653. Epub 2016 Nov 24.

Department of Neurosurgery, College of Medicine, Kyung Hee University, Kyung Hee University Hospital, Seoul, Korea. Electronic address:

Objective: Isolated dissections that develop on the posterior inferior cerebellar artery (PICA) require intensive treatment because of their potential fatality. However, because of the rarity of these dissections, the optimal treatment has not yet been established.

Methods: We retrospectively reviewed the clinical records of all patients who underwent any PICA dissection treatment in our institute over the last 4 years. Ten patients were enrolled, including 7 patients with subarachnoid hemorrhage (SAH) and 3 with PICA territory infarction. Dissection was seen at the proximal portion in 8 patients, whereas the remaining 2 patients showed distal PICA dissecting aneurysms.

Results: Among the 7 patients with hemorrhage, 5 were actively treated (trapping and bypass, 2 patients; surgical clipping, 1 patient; coil embolization, 2 patients). Conservative management was performed in the other 2 patients. Among the 3 patients with infarction, 2 received conservative treatment. Endovascular treatment was performed in 1 patient, who showed rapid progression, aneurysm formation, and conversion to massive SAH within 10 days after the initial attack. Although 7 patients showed relatively good outcomes (modified Rankin Scale score, ≤2) after 30 days of follow-up, 1 patient had a final modified Rankin Scale score of 3. In addition, the other 2 patients (1 in each group) died as a result of major SAH.

Conclusions: Given the dynamic clinical course and potential fatality of PICA dissection, meticulous evaluation, intensive treatment with a diverse range of modalities, and proper follow-up are required for patients with PICA dissection to achieve favorable outcomes.
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http://dx.doi.org/10.1016/j.wneu.2016.11.094DOI Listing
February 2017

Emergent Double-barrel Bypass Shortly after Intravenous Administration of Recombinant Tissue Plasminogen Activator for Acute Ischemic Stroke.

J Cerebrovasc Endovasc Neurosurg 2016 Sep 30;18(3):258-263. Epub 2016 Sep 30.

Department of Neurosurgery, Busan-Ulsan Regional Cardio-Cerebrovascular Center, Medical Science Research Center, College of Medicine, Dong-A University, Busan, Korea.

Although intravenous recombinant tissue plasminogen activator (IV rt-PA) is effective in many cases of acute ischemic stroke, the neurologic symptoms can worsen after IV rt-PA because of sustained vessel occlusion. For such cases, several reperfusion modalities are available, including intra-arterial thrombolysis (IAT), carotid endarterectomy, and superficial temporal artery-middle cerebral artery (STA-MCA) bypass. Invasive procedures, such as major surgery, should be generally avoided within 24 hours after the administration of IV rt-PA. A 66-year-old man with no previous medical history developed left hemiparesis. A computed tomography scan revealed no acute lesion and he received IV rt-PA within 1.5 hours after symptom onset. Emergent magnetic resonance imaging showed significant diffusion-perfusion mismatch. He received IAT 2 hours after IV rt-PA administration, but IAT failed because of total occlusion of the cervical internal carotid artery. We initially planned to perform STA-MCA bypass the next morning because he had received IV rt-PA, but, 8 hours after IV rt-PA administration, his hemiparesis worsened from motor grade 3/4 to motor grade 1/2. Because of the large perfusion defect in both MCA divisions, double-barrel STA-MCA bypass was performed 10 hours after IV rt-PA administration. His symptoms rapidly improved after surgery and his modified Rankin Scale score 3 months later was grade 0. We suggest that emergent double-barrel bypass can be a viable option in patients who have perfusion defects of both MCA divisions in acute ischemic stroke after IV rt-PA administration.
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http://dx.doi.org/10.7461/jcen.2016.18.3.258DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5104852PMC
September 2016

The Relationship Between Estrogen Receptor, Progesterone Receptor and Human Epidermal Growth Factor Receptor 2 Expression of Breast Cancer and the Retention Index in Dual Phase (18)F-FDG PET/CT.

Nucl Med Mol Imaging 2016 Sep 11;50(3):246-54. Epub 2016 Apr 11.

Department of Nuclear Medicine, Korea Cancer Center Hospital, Korea Institute of Radiological and Medical Sciences (KIRAMS), 75, Nowon-ro, Nowon-gu, Seoul, 139-706 Republic of Korea.

Purpose: This study investigates the correlation of retention index (RI) using the dual phase FDG PET/CT scan with the breast cancer biomarkers.

Methods: A total of 55 patients with breast cancer underwent dual phase FDG PET/CT scans (60 and 120 min after FDG injection) before treatment. SUVmax and SUVmean of the primary breast tumors were measured, then the percent change of SUVmax and SUVmean between the two scans were calculated, and denoted as RImax and RImean, respectively. After the surgical resection of the breast tumor, the status of biomarkers (ER, PR, and HER-2) was evaluated in the postsurgical specimen.

Results: RImean was significantly higher in ER (-) (median, 16.2; IQR, 10.8-21.0) or HER-2 (+) (median, 16.1; IQR, 10.7-21.6) tumors than in ER (+) tumors (median, 9.9; IQR, 5.5-15.3) or HER-2 (-) tumors (median, 10.5; IQR, 5.5-16.1). However, there were no significant differences of SUVmax or RImax according to the ER or HER-2 status. There were no significant differences of any PET parameters between PR (+) and PR (-) tumors. Based off ROC curve analyses, RImean predicted the ER (+) tumors (AUC, 0.699; p = 0.006), and HER-2 (+) tumors (AUC, 0.674; p = 0.022), but not the PR (+) tumors. However, neither SUVmax nor RImax predicted ER (+), PR (+), or HER-2 (+) tumors.

Conclusions: Retention index of SUVmean can reflect the ER and HER-2 status of breast cancers. Higher retention index of SUVmean might associate with lower ER expression and higher HER-2 expression.
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http://dx.doi.org/10.1007/s13139-016-0412-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4977256PMC
September 2016

Emergence of functional subnetworks in layer 2/3 cortex induced by sequential spikes in vivo.

Proc Natl Acad Sci U S A 2016 Mar 22;113(10):E1372-81. Epub 2016 Feb 22.

Max Planck Florida Institute for Neuroscience, Jupiter, FL 33458; Max Planck Institute of Neurobiology, 82152 Martinsried, Germany

During cortical circuit development in the mammalian brain, groups of excitatory neurons that receive similar sensory information form microcircuits. However, cellular mechanisms underlying cortical microcircuit development remain poorly understood. Here we implemented combined two-photon imaging and photolysis in vivo to monitor and manipulate neuronal activities to study the processes underlying activity-dependent circuit changes. We found that repeated triggering of spike trains in a randomly chosen group of layer 2/3 pyramidal neurons in the somatosensory cortex triggered long-term plasticity of circuits (LTPc), resulting in the increased probability that the selected neurons would fire when action potentials of individual neurons in the group were evoked. Significant firing pattern changes were observed more frequently in the selected group of neurons than in neighboring control neurons, and the induction was dependent on the time interval between spikes, N-methyl-D-aspartate (NMDA) receptor activation, and Calcium/calmodulin-dependent protein kinase II (CaMKII) activation. In addition, LTPc was associated with an increase of activity from a portion of neighboring neurons with different probabilities. Thus, our results demonstrate that the formation of functional microcircuits requires broad network changes and that its directionality is nonrandom, which may be a general feature of cortical circuit assembly in the mammalian cortex.
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http://dx.doi.org/10.1073/pnas.1513410113DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4791016PMC
March 2016

Tumor SUVmax Normalized to Liver Uptake on (18)F-FDG PET/CT Predicts the Pathologic Complete Response After Neoadjuvant Chemoradiotherapy in Locally Advanced Rectal Cancer.

Nucl Med Mol Imaging 2014 Dec 1;48(4):295-302. Epub 2014 Aug 1.

Department of Nuclear Medicine, Korea Cancer Center Hospital, 75, Nowon-ro, Nowon-gu, Seoul, 139-706 Republic of Korea.

Purpose: This study investigates the feasibility of using (18)F-fluorodeoxyglucose positron emission tomography/computed tomography ((18)F-FDG PET/CT) to predict the pCR (pathologic complete response) rate after neoadjuvant chemoradiotherapy (NCRT) in patients with locally advanced rectal cancer.

Methods: A total of 88 patients with locally advanced rectal cancer were retrospectively analyzed. All patients were treated with NCRT, followed by radical surgery, and (18)F-FDG PET/CT was performed before and after NCRT. For a semiquantitative assessment, a volume of interest was drawn, including the whole tumor region, and the maximum SUV (SUVmax), SUVmax normalized to liver uptake (SLR), SUVmax normalized to blood pool uptake (SBR), the metabolic tumor volume at SUV 2.0 (MTV[2.0]), SUV 2.5 (MTV[2.5]), and SUV 3.0 (MTV[3.0]) were measured. In addition, their percentage changes after NCRT were assessed. The pCR was verified through a histologic examination of postsurgical specimens. A receiver operating characteristic curve analysis was conducted to predict the pCR by using these PET parameters.

Results: The pCR was predicted in 17 patients (19 %). The values of the area under the curve (AUC) for predicting the pCR were 0.774 for SUVmax after NCRT, 0.826 for SLR after NCRT, 0.815 for SBR after NCRT, 0.724 for MTV(2.5) after NCRT, 0.729 for the percentage change in SUVmax, 0.700 for the percentage change in SLR, and 0.749 for the percentage change in MTV (2.5). Among these PET parameters, SLR after NCRT showed the highest AUC value. The optimal criterion, sensitivity, specificity, and accuracy of SLR after NCRT for predicting the pCR were ≤1.41, 88 %, 65 %, and 68 %, respectively.

Conclusions: F-FDG PET was found to be useful for predicting the pCR after NCRT in patients with locally advanced rectal cancer. Among various PET parameters, SUVmax normalized to liver uptake after NCRT was the best predictor of the pCR.
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http://dx.doi.org/10.1007/s13139-014-0289-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4571668PMC
December 2014

Saccharification of sunflower stalks using lignocellulases from a fungal consortium comprising Pholiota adiposa and Armillaria gemina.

Bioprocess Biosyst Eng 2015 Sep 30;38(9):1645-53. Epub 2015 Apr 30.

Department of Chemical Engineering, Konkuk University, 1 Hwayang-Dong, Gwangjin-Gu, Seoul, 143-701, Republic of Korea.

Lignocellulases from Armillaria gemina and Pholiota adiposa are efficient in hydrolyzing aspen and poplar biomass, respectively. In the present study, lignocellulosic enzymes obtained from a fungal consortium comprising P. adiposa and A. gemina were used for the saccharification of sunflower stalks. Sunflower stalks were thermochemically pretreated using 2 % NaOH at 50 °C for 24 h. The saccharification process parameters including substrate concentration, enzyme loading, pH, and temperature were optimized using response surface methodology to improve the saccharification yield. The highest enzymatic hydrolysis (84.3 %) was obtained using the following conditions: enzyme loading 10 FPU/g-substrate, substrate 5.5 %, temperature 50 °C, and pH 4.5. The hydrolysis yield obtained using the enzymes from the fungal consortium was equivalent to that obtained using a mixture of commercial enzymes Celluclast and Novozyme β-glucosidase. Addition of up to 500 ppm of heavy metal ions (As, Cu, Fe, Mn, Ni, Pb, and Zn) during saccharification did not significantly affect the saccharification yield. Thus, the biomass grown for phytoremediation of heavy metals can be used for the production of reducing sugars followed by ethanol fermentation.
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http://dx.doi.org/10.1007/s00449-015-1406-7DOI Listing
September 2015

Evaluation of stability after orthognathic surgery with minimal orthodontic preparation: comparison according to 3 types of fixation.

J Craniofac Surg 2014 May;25(3):911-5

From the Departments of *Oral and Maxillofacial Surgery and †School of Dentistry, Seoul National University; and ‡Orthodontics, Section of Dentistry, Seoul National University Bundang Hospital, Seoul, Korea.

This study was performed to evaluate the patterns and amount of postsurgical relapse after mandibular setback surgery with minimal orthodontic preparation. We also compared the stability of plate according to types. From January 2009 to February 2012, 26 patients (13 males, 13 females) at Seoul National University Bundang Hospital were identified. All patients underwent presurgical orthodontic treatment in less than 6 months and had mandibular setback surgery. Lateral cephalograms were taken presurgically (T0), immediately after surgery (T1), and 6 months after surgery (T2). To evaluate surgical change and surgical relapse, linear and angular measurements were performed, and results were analyzed. Comparison of the vertical and horizontal relapses between groups (group 1: sliding plate, group 2: conventional metal plate, group 3: resorbable plate) was also performed. The overall mandibular relapse was 2.80 (SD, 3.86) mm (pogonion) and 3.85 (SD, 4.44) mm (menton) anteriorly, and 1.2 (SD, 3.39) (pogonion) and 1.47 (SD, 3.48) mm (menton) superiorly. There was no significant difference among the 3 groups, however (P > 0.05). When mandibular setback surgery was performed, surgical relapse would occur anteriorly and superiorly. Significant difference can hardly be found among the 3 groups in terms of the amount of vertical and horizontal relapses.
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http://dx.doi.org/10.1097/SCS.0000000000000609DOI Listing
May 2014

Characterization of a β-1,4-mannanase from a newly isolated strain of Pholiota adiposa and its application for biomass pretreatment.

Bioprocess Biosyst Eng 2014 Sep 5;37(9):1817-24. Epub 2014 Mar 5.

Department of Chemical Engineering, Konkuk University, 1 Hwayang-Dong, Gwangjin-Gu, Seoul, 143-701, Republic of Korea.

A highly efficient β-1,4-mannanase-secreting strain, Pholiota adiposa SKU0714, was isolated and identified on the basis of its morphological features and sequence analysis of internal transcribed spacer rDNA. P. adiposa β-1,4-mannanase was purified to homogeneity from P. adiposa culture supernatants by one-step chromatography on a Sephacryl gel filtration column. P. adiposa β-1,4-mannanase showed the highest activity toward locust bean gum (V max = 1,990 U/mg protein, K m = 0.12 mg/mL) ever reported. Its internal amino acid sequence showed homology with hydrolases from the glycoside hydrolase family 5 (GH5), indicating that the enzyme is a member of the GH5 family. The saccharification of commercial mannanase and P. adiposa β-1,4-mannanase-pretreated rice straw by Celluclast 1.5L (Novozymes) was compared. In comparison with the commercial Novo Mannaway(®) (113 mg/g-substrate), P. adiposa β-1,4-mannanase-pretreated rice straw released more reducing sugars (141 mg/g-substrate). These properties make P. adiposa β-1,4-mannanase a good candidate as a new commercial β-1,4-mannanase to improve biomass pretreatment.
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http://dx.doi.org/10.1007/s00449-014-1156-yDOI Listing
September 2014
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