Su-Yeon Park

Association of Metabolites with Obesity and Type 2 Diabetes Based on FTO Genotype

The single nucleotide polymorphism rs9939609 of the gene FTO, which encodes fat mass and obesity–associated protein, is strongly associated with obesity and type 2 diabetes (T2D) in multiple populations; however, the underlying mechanism of this association is unclear. The present study aimed to investigate FTO genotype–dependent metabolic changes in obesity and T2D. To elucidate metabolic dysregulation associated with disease risk genotype, genomic and metabolomic datasets were recruited from 2,577 participants of the Korean Association REsource (KARE) cohort, including 40 homozygous carriers of the FTO risk allele (AA), 570 heterozygous carriers (AT), and 1,967 participants carrying no risk allele (TT). A total of 134 serum metabolites were quantified using a targeted metabolomics approach. Through comparison of various statistical methods, seven metabolites were identified that are significantly altered in obesity and T2D based on the FTO risk allele (adjusted p < 0.05). These identified metabolites are relevant to phosphatidylcholine metabolic pathway, and previously reported to be metabolic markers of obesity and T2D. In conclusion, using metabolomics with the information from genome-wide association studies revealed significantly altered metabolites depending on the FTO genotype in complex disorders. This study may contribute to a better understanding of the biological mechanisms linking obesity and T2D.

Nocturnal hypoxia in ALS is related to cognitive dysfunction and can occur as clusters of desaturations.

Background Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease that leads to progressive weakness of the respiratory and limb muscles. Consequently, most patients with ALS exhibit progressive hypoventilation, which worsens during sleep. The aim of this study was to evaluate the relationship between nocturnal hypoxia and cognitive dysfunction and to assess the pattern of nocturnal hypoxia in patients with ALS. Method Twenty-five patients with definite or probable ALS underwent neuropsychologic testing, nocturnal pulse oximetry, and capnography. Patients were grouped according to the presence of nocturnal hypoxia (SpO2<95% for ≥10% of the night) and their clinical characteristics and cognitive function were compared. Results Compared to patients without nocturnal hypoxia, those with nocturnal hypoxia (n = 10, 40%) had poor memory retention (p = 0.039) and retrieval efficiency (p = 0.045). A cluster-of-desaturation pattern was identified in 7 patients (70%) in the Hypoxia Group. Conclusions These results suggest that nocturnal hypoxia can be related to cognitive dysfunction in ALS. In addition, a considerable number of patients with ALS may be exposed to repeated episodes of deoxygenation–reoxygenation (a cluster-of-desaturation pattern) during sleep, which could be associated with the generation of reactive oxygen species. Further studies are required to define the exact causal relationships between these phenomena, the exact manifestations of nocturnal cluster-of-desaturation patterns, and the effect of clusters of desaturation on ALS progression.

Ischemic Neuropathy Associated with Livedoid Vasculitis

Background Livedoid vasculitis is a chronic dermatological problem with an unclear etiology. Clinical findings are petechiae with painful ulcers in both lower extremities, which heal to become hyperpigmented and porcelain-white satellite lesions. There are only a few reported cases of livedoid vasculitis presenting in combination with peripheral neuropathy. Case Report We report the first case of a Korean patient presenting with mononeuritis multiplex combined with livedoid vasculitis, which was confirmed by electrophysiological and pathological studies. Conclusions Our report supports the possible vaso-occlusive etiology of livedoid vasculitis in multifocal ischemic neuropathy.

Up-Regulation of the Receptor for Advanced Glycation End Products in the Skin Biopsy Specimens of Patients with Severe Diabetic Neuropathy

Background and Purpose The receptor for advanced glycation end products (RAGE) may contribute to the development of diabetic neuropathy. To assess its relevance in humans, this study examined the expression of RAGE in the skin biopsy samples of patients with diabetes mellitus, and investigated its correlation with intraepidermal nerve-fiber density (IENFD) and clinical measures of neuropathy severity. Methods Forty-four patients who either had type 2 diabetes or were prediabetes underwent clinical evaluation and a 3-mm skin punch biopsy. The clinical severity of their neuropathy was assessed using the Michigan Diabetic Neuropathy Score. IENFD was measured along with immunohistochemical staining for RAGE in 29 skin biopsy samples. The expression of RAGE was also quantified by real-time reverse-transcription PCR in the remaining 15 patients. Results RAGE was localized mostly in the dermal and subcutaneous vascular endothelia. The staining was more intense in patients with a lower IENFD (p=0.004). The quantity of RAGE mRNA was significantly higher in patients with severe neuropathy than in those with no or mild neuropathy (p=0.003). The up-regulation of RAGE was related to dyslipidemia and diabetic nephropathy. There was a trend toward decreased sural nerve action-potential amplitude and slowed peroneal motor-nerve conduction with increasing RAGE expression. Conclusions The findings of this study demonstrate up-regulation of RAGE in skin biopsy samples from patients with diabetic neuropathy, supporting a pathogenic role of RAGE in the development of diabetic neuropathy.

A novel double mutation in cis in MFN2 causes Charcot-Marie-Tooth neuropathy type 2A.

Mutations in mitofusin-2 (MFN2) are the most common cause of axonal Charcot–Marie–Tooth (CMT) neuropathy. Herein, we report a novel double mutation in cis (c.[474+4A>G; 668T>A]) in a Korean family with late-onset autosomal dominant mild axonal CMT. Transcriptional analysis demonstrated aberrant splicing with exon 5 skipping and premature termination of translation before the missense mutation in exon 7. Interestingly, the aberrant splicing was incomplete, with some of the primary transcripts being spliced correctly and expressing the downstream missense mutation. The pathogenic relevance of the missense mutation would not be appreciated without the leaky aberrant splicing and the insensitivity of MFN2 to haploinsufficiency.

A prospective comparative assessment of the accuracy of the FibroScan in evaluating liver steatosis

Background/aims Recent studies have demonstrated the utility of the FibroScan® device in diagnosing liver steatosis, but its usefulness has not been thoroughly appraised. We investigated the usefulness of the controlled attenuation parameter (CAP) in detecting and quantifying liver steatosis. Methods A prospective analysis was applied to 79 chronic liver disease patients who underwent a liver biopsy, a FibroScan investigation, ultrasonography, and hepatic steatosis index (HSI). The presence and degree of steatosis as measured by the FibroScan device, ultrasonography and HSI were compared with the results for the liver biopsy tissue. Results There was substantial concordance between the liver biopsy results and the CAP as evaluated by the kappa (κ) index test for detecting liver steatosis (κCAP = 0.77, P<0.001; κultrasonography = 0.60, P<0.001; κHSI = 0.47, P<0.001). The areas under the receiver operating characteristic curve (AUROCs) of the CAP, ultrasonography, and HSI were 0.899 [95% confidence interval (CI) = 0.826–0.972)], 0.859 (95% CI = 0.779–0.939), and 0.766 (95% CI = 0.655–0.877), respectively. The optimal CAP cutoff value for differentiating between normal and hepatic steatosis was 247 dB/m, which produced sensitivity and specificity values of 91.9% and 85.7%, respectively, as well as a positive predictive value of 85.0% and a negative predictive value of 92.3%. Conclusion The CAP produces results that are highly concordant with those of a liver biopsy in detecting steatosis. Therefore, the CAP is a noninvasive and reliable tool for evaluating liver steatosis, even in the early stages.

SU‐F‐T‐317: Skin Exposure Outside the Treatment Field During Treatment of Breast Cancer with Tri‐Co‐60 MR‐IGRT System

PURPOSE To investigate exposure outside the treatment field when treating breast cancer with tri-Co-60 magnetic resonance (MR) image guided radiation therapy (IGRT) system. METHODS A total of 7 patients who treated with accelerated partial breast irradiation (APBI) technique were selected prospectively for this study (prescription dose = 38.5 Gy in 10 fractions). Every patient treated with two plans, one was an initial plan and the other was an adaptive plan generated after finishing 5 fractions (a total of 14 plans). Every plan was calculated with and without magnetic field in the treatment planning system. The EBT3 films were attached on the front and the back of 1 cm bolus, and then it was placed on the patient body vertically to cover patients jaw and shoulder. After measurements, the maximum point dose and the mean dose of whole area of EBT3 film were acquired. RESULTS In the treatment plan with magnetic field, low dose stream outside the patient body was observed, almost reaching the patients jaw or shoulder, while it was not observed without magnetic field. The average values of the measured maximum and mean doses at the front of bolus were 30.1 ± 11.1 cGy (7.8% of the daily dose) and 14.7 ± 3.3 cGy (3.8%), respectively. At the back of bolus, those values were 6.0 ± 1.9 cGy (1.6%) and 5.1 ± 1.6 cGy (1.3%), respectively. The largest maximum dose at the front was 54.2 cGy (14.1%) while it was 20.7 cGy (5.4%) at the back. The average decrease of the maximum dose by the bolus was 24.0 ± 11.0 cGy. CONCLUSION Due to magnetic field, dose stream outside the patient body can be generated during breast cancer treatment with the tri-Co-60 MR-IGRT system. Since this dose stream irradiated skin outside the treatment field, it should be shielded. This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIP) (No. 2015R1C1A1A01054192).

SU‐F‐T‐318: Sensitivity and Stability of OSLDs with Filled Deep Electron/hole Traps Under Pre‐Irradiation and Bleaching Conditions

PURPOSE This work evaluated the characteristics of optically stimulated luminescence dosimeters (OSLDs) with fully filled deep electron/hole traps (OSLDfull) with the bleaching conditions according to the accumulated dose. METHODS The OSLDs were first pre-irradiated with a Co-60 gamma ray at more than 5 kGy, so as to fill the deep electron and hole traps. Using a 6-MV beam, the OSLDfull characteristics were investigated in terms of the full bleaching, fading, dose linearity, and dose sensitivity obtained in response to the accumulated dose values. To facilitate a comparison of the dose sensitivity, OSLDs with un-filled deep electron/hole traps (OSLDempty) were investigated in the same manner. A long-pass filter was used to exclude bleaching-source wavelengths of less than 520 nm. Various bleaching time and wavelength combinations were used in order to determine the optimal bleaching conditions for the OSLD full. RESULTS The fading for the OSLDfull exhibited stable signals after 8 min, for both 1- and 10-Gy. For 4-h bleaching time and an unfiltered bleaching device, the supralinear index values for the OSLDfull were 1.003, 1.002, 0.999, and 1.001 for doses of 2, 4, 7, and 10 Gy, respectively. For a 65-Gy accumulated dose with a 5-Gy fraction, no variation in dose sensitivity was obtained for the OSLDfull, within a standard deviation of 0.85%, whereas the OSLDempty dose sensitivity decreased by approximately 2.3% per 10 Gy. The filtered bleaching device yielded a highly stable sensitivity for OSLDfull, independent of bleaching time and within a standard deviation of 0.71%, whereas the OSLDempty dose sensitivity decreased by approximately 4.2% per 10 Gy for an accumulated dose of 25 Gy with a 5-Gy fraction. CONCLUSION Under the bleaching conditions determined in this study, clinical dosimetry with OSLDfull is highly stable, having an accuracy of 1% with no change in dose sensitivity or linearity at clinical doses. This work was supported by a National Research Foundation of Korea (NRF) grant, funded by the Korea government (MISP) (No. 2014M2B2A4031164), and by the Korea Health Technology R&D Project through the Korea Health Industry Development Institute (KHIDI), funded by the Ministry of Health & Welfare, Republic of Korea (HI14C3459).

Quantative eeg characteristics of periodic lateralized epileptiform discharges according to benzodiazepine responsiveness

Background: Periodic lateralized epileptiform discharges (PLEDs) are associated with altered consciousness in 75% of patients. Major controversy about PLEDs is whether they are ictal or interictal phenomenon. Diagnosis of non-convulsive status epilepticus is often guided by response to benzodiazepine. We conducted a study to evaluate quantitative differences of EEG activity with PLEDs according to their response to acute benzodiazepine trial. Methods: Nineteen patients with altered consciousness (stupor or coma) for whom the electroencephalography (EEG) recording with acute benzodiazepine trial was undertaken within 24 hours of onset of altered consciousness were retrospectively enrolled. Morphology of PLEDs including amplitude, frequency, and variability of the frequency was analyzed. Quantitative analysis of EEGs includes spectral power, spectral coherence, and graph theory analysis. Results of the analyses were compared between patients whose PLEDs were abolished by benzodiazepine (BDZ-R group) and those whose PLEDs persisted (BDZ-NR group). Results: Morphologic variables were not different between two groups. In BDZ-R group, alpha-1 activity was increased in both frontopolar areas. Beta activity was also increased in both frontal areas while delta activity was reduced. In BDZ-R group, alpha-1 and beta activities were more coherent between bilateral hemispheres in frontal, anterior temporal, and central areas. Coherence line topographic map also revealed more bilaterally symmetric pattern in BDZ-R group. Network characteristics revealed by graph theory analysis did not differ between the two groups. Conclusions: Greater higher frequency activity (alpha-1 and beta) and lesser lower frequency activity (delta) in frontal areas, and more coherent activity in higher frequency band between hemispheres were associated with benzodiazepine responsiveness. J Korean Neurol Assoc 33(4):288-296, 2015