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1.  Headache relief after anterior cervical discectomy: post hoc analysis of a randomized investigational device exemption trial 
Journal of neurosurgery. Spine  2014;21(2):217-222.
The authors analyzed headache relief after anterior cervical discectomy. Headache may be relieved after anterior cervical discectomy, but the mechanism is unknown. If headaches were directly referred from upper cervical pathology, more headache relief would be expected from surgery performed at higher cervical levels. If spinal kinesthetics were the mechanism, then headache relief may differ between arthroplasty and fusion. Headache relief after anterior cervical discectomy was quantified by the operated disc level and by the method of operation (arthroplasty vs arthrodesis).
The authors performed a post hoc analysis of an artificial disc trial. Data on headache pain were extracted from the Neck Disability Index (NDI) questionnaire.
A total of 260 patients underwent single-level arthroplasty or arthodesis. Preoperatively, 52% reported NDI headache scores of 3 or greater, compared with only 13%–17% postoperatively. The model-based mean NDI headache score at baseline was 2.5 (95% CI 2.3–2.7) and was reduced by 1.3 points after surgery (95% CI 1.2–1.4, p < 0.001). Higher cervical levels were associated with a greater degree of preoperative headache, but there was no association with headache relief. There was no significant difference in headache relief between arthroplasty and arthrodesis.
Most patients with symptomatic cervical spondylosis have headache as a preoperative symptom (88%). Anterior cervical discectomy with both arthroplasty and arthrodesis is associated with a durable decrease in headache. Headache relief is not related to the level of operation. The mechanism for headache reduction remains unclear.
PMCID: PMC4386608  PMID: 24836655
headache; spine; cervicogenic; spondylosis; cervical
2.  Detection of Low Back Pain Using pH Level-Dependent Imaging of the Intervertebral Disc Using the Ratio of R1ρ Dispersion and –OH Chemical Exchange Saturation Transfer (RROC) 
Magnetic resonance in medicine  2014;73(3):1196-1205.
Low pH is associated with intervertebral disc (IVD)-generated low back pain (LBP). The purpose of this work was to develop an in vivo pH level-dependent magnetic resonance imaging (MRI) method for detecting discogenic LBP, without using exogenous contrast agents.
The ratio of R1ρ dispersion and chemical exchange saturation transfer (CEST) (RROC) was used for pH-level dependent imaging of the IVD while eliminating the effect of labile proton concentration. The technique was validated by numerical simulations and studies on phantoms and ex vivo porcine spines. Four male (ages 42.8 ± 18.3) and two female patients (ages 55.5 ± 2.1) with LBP and scheduled for discography were examined with the method on a 3.0 Tesla MR scanner. RROC measurements were compared with discography outcomes using paired t-test.
Simulation and phantom results indicated RROC is a concentration independent and pH level-dependent technique. Porcine spine study results found higher RROC value was related to lower pH level. Painful discs based on discography had significant higher RROC values than those with negative diagnosis (P < 0.05).
RROC imaging is a promising pH level dependent MRI technique that has the potential to be a noninvasive imaging tool to detect painful IVDs in vivo.
PMCID: PMC4511600  PMID: 24700573
Intervertebral disc; pH imaging; RROC; R1ρ dispersion; CEST
3.  Therapeutic sustainability and durability of coflex interlaminar stabilization after decompression for lumbar spinal stenosis: a four year assessment 
Approved treatment modalities for the surgical management of lumbar spinal stenosis encompass a variety of direct and indirect methods of decompression, though all have varying degrees of limitations and morbidity which potentially limit the efficacy and durability of the treatment. The coflex® interlaminar stabilization implant (Paradigm Spine, New York, NY), examined under a United States Food and Drug Administration (US FDA) Investigational Device Exemption (IDE) clinical trial, is shown to have durable outcomes when compared to posterolateral fusion in the setting of post-decompression stabilization for stenotic patients. Other clinical and radiographic parameters, more indicative of durability, were also evaluated. The data collected from these parameters were used to expand the FDA composite clinical success (CCS) endpoint; thus, creating a more stringent Therapeutic Sustainability Endpoint (TSE). The TSE allows more precise calculation of the durability of interlaminar stabilization (ILS) when compared to the fusion control group.
A retrospective analysis of data generated from a prospective, randomized, level-1 trial that was conducted at 21 US sites was carried out. Three hundred forty-four per-protocol subjects were enrolled and randomized to ILS or fusion after decompression for lumbar stenosis with up to grade 1 degenerative spondylolisthesis. Clinical, safety, and radiographic data were collected and analyzed in both groups. Four-year outcomes were assessed, and the TSE was calculated for both cohorts. The clinical and radiographic factors thought to be associated with therapeutic sustainability were added to the CCS endpoints which were used for premarket approval (PMA).
Success rate, comprised of no second intervention and an ODI improvement of ≥ 15 points, was 57.6% of ILS and 46.7% of fusion patients (p = 0.095). Adding lack of fusion in the ILS cohort and successful fusion in the fusion cohort showed a CCS of 42.7% and 33.3%, respectively. Finally, adding adjacent level success to both cohorts and maintenance of foraminal height in the coflex cohort showed a CCS of 36.6% and 25.6%, respectively. With additional follow-up to five years in the U.S. PMA study, these trends are expected to continue to show the superior therapeutic sustainability of ILS compared to posterolateral fusion after decompression for spinal stenosis.
There are clear differences in both therapeutic sustainability and intended clinical effect of ILS compared to posterolateral fusion with pedicle screw fixation after decompression for spinal stenosis. There are CCS differences between coflex and fusion cohorts noted at four years post-op similar to the trends revealed in the two year data used for PMA approval. When therapeutic sustainability outcomes are added to the CCS, ILS is proven to be a sustainable treatment for stabilization of the vertebral motion segment after decompression for lumbar spinal stenosis.
PMCID: PMC4442626  PMID: 26056630
Lumbar spinal stenosis; interlaminar stabilization implant; Posterolateral fusion
4.  MicroRNA-31 functions as a tumor suppressor by regulating cell cycle and epithelial-mesenchymal transition regulatory proteins in liver cancer 
Oncotarget  2015;6(10):8089-8102.
MicroRNA-31 (miR-31) is among the most frequently altered microRNAs in human cancers and altered expression of miR-31 has been detected in a large variety of tumor types, but the functional role of miR-31 still hold both tumor suppressive and oncogenic roles in different tumor types. MiR-31 expression was down-regulated in a large cohort of hepatocellular carcinoma (HCC) patients, and low expression of miR-31 was significantly associated with poor prognosis of HCC patients. Ectopic expression of miR-31 mimics suppressed HCC cell growth by transcriptional deregulation of cell cycle proteins. Additional study evidenced miR-31 directly to suppress HDAC2 and CDK2 expression by inhibiting mRNA translation in HCC cells. We also found that ectopic expression of miR-31 mimics reduced metastatic potential of HCC cells by selectively regulating epithelial-mesenchymal transition (EMT) regulatory proteins such as N-cadherin, E-cadherin, vimentin and fibronectin. HCC tissues derived from chemical-induced rat liver cancer models validated that miR-31 expression is significantly down-regulated, and that those cell cycle- and EMT-regulatory proteins are deregulated in rat liver cancer. Overall, we suggest that miR-31 functions as a tumor suppressor by selectively regulating cell cycle and EMT regulatory proteins in human hepatocarcinogenesis providing a novel target for the molecular treatment of liver malignancies.
PMCID: PMC4480737  PMID: 25797269
Hepatocellular carcinoma; microRNA-31; CDK2; HDAC2; cell cycle
5.  Cardiovascular Screening in Asymptomatic Adolescents with Metabolic Syndrome 
In recent days, the prevalence of childhood metabolic syndrome (MS) has increased substantially due to the increasing rate of childhood obesity on a global scale. The aims of this study were to detect the important parameters and provide the screening system to prevent cardiovascular disease in adolescents with MS.
Ninety one male adolescents were divided into two groups based on the presence or absence of MS. Anthropometric measurement and laboratory study were studied. Intimal medial thickness and pulse wave velocity were estimated. Left ventricular mass index (LVMI), ejection fraction, myocardial velocity, strain and strain rate were measured by tissue Doppler imaging and strain rate imaging.
The prevalence of MS was 7.7%. Weight, body mass index (BMI), waist circumference (WC), glucose, insulin, homeostasis model assessment of insulin resistance, triglyceride and LVMI were significantly increased in the MS group. High density lipoprotein-cholesterol (HDL-C), peak early diastolic myocardial velocity (e'), systolic myocardial velocity (s') and global longitudinal strain were significantly lower in the MS group. In univariant analysis, LVMI was significantly correlated with BMI, WC, fat %, fat mass, systolic blood pressure, alanine aminotransferase, total cholesterol (TC) and low density lipoprotein-cholesterol. e' was significantly correlated with BMI, fat %, fat mass, and HDL-C. Global circumferential strain had significant correlation with glucose and TC. Basal anterolateral strain rate was significantly correlated with weight, BMI, WC, fat %, and fat mass.
LVMI, strain and strain rate are practical and accurate parameters for assessment of left ventricular function in adolescents with MS.
PMCID: PMC4398779  PMID: 25883751
Metabolic syndrome; Adolescent; Tissue Doppler imaging; Strain rate
6.  Effects of Different Types of Contraction in Abdominal Bracing on the Asymmetry of Left and Right Abdominal Muscles 
Journal of Physical Therapy Science  2014;26(12):1843-1845.
[Purpose] The purpose of this study was to investigate the effective strength levels of abdominal muscle contraction using the bracing contraction method. [Subjects] The experiment was conducted with 31 healthy male (M=15) and female (F=16) adults attending D University in Busan; all participants had less than obesity level BMI (BMI<30). [Methods] Bracing contraction was performed by the subjects in the hook-lying position at maximum and minimum pressure levels, five times each, using a Pressure Biofeedback Unit (PBU), and the mean measurement value was calculated. The maximum pressure level was set at 100% and the half maximum pressure level was set at 50%. Each subject’s left and right abdominal muscle thicknesses were then measured by ultrasound imaging in each state: at rest, 100% contraction, and 50% contraction. [Results] No significant differences were found between the left and right sides of the transversus abdominis (TrA) at rest, 50%, or 100% contraction. The external oblique abdominis (EO) and internal oblique abdominis (IO) showed no significant difference at rest or at the 50% contraction. However, a significant difference was noted at 100% contraction for the EO and IO. [Conclusion] Application of abdominal contraction using bracing can achieve symmetry in the left and right abdominal muscles at less than the maximum contractile strength. The occurrence of asymmetry in the left and right abdominal muscles at the maximum contractile strength suggests that the most suitable contractile strength in this exercise is less than the maximum contractile strength.
PMCID: PMC4273038  PMID: 25540478
Abdominal bracing; Symmetry; Ultrasound imaging
7.  Multi-center, Prospective, Randomized, Controlled Investigational Device Exemption Clinical Trial Comparing Mobi-C Cervical Artificial Disc to Anterior Discectomy and Fusion in the Treatment of Symptomatic Degenerative Disc Disease in the Cervical Spine 
Anterior cervical discectomy and fusion (ACDF) is the gold standard for treating symptomatic cervical disc degeneration. Cervical total disc replacements (TDRs) have emerged as an alternative for some patients. The purpose of this study was to evaluate the safety and effectiveness of a new TDR device compared with ACDF for treating single-level cervical disc degeneration.
This was a prospective, randomized, controlled, multicenter Food and Drug Administration (FDA) regulated Investigational Device Exemption (IDE) study. A total of 245 patients were treated (164 TDR: 81 ACDF). The primary outcome measure was overall success based on improvement in Neck Disability Index (NDI), no subsequent surgical interventions, and no adverse events (AEs) classified as major complications.
Secondary outcome measures included SF-12, visual analog scale (VAS) assessing neck and arm pain, patient satisfaction, radiographic range of motion, and adjacent level degeneration. Patients were evaluated preoperatively and postoperatively at 6 weeks, 3, 6, 12, 18, and 24 months. The hypothesis was that the TDR success rate was non-inferior to ACDF at 24 months.
Overall success rates were 73.6% for TDR and 65.3% for ACDF, confirming non-inferiority (p < 0.0025). TDR demonstrated earlier improvements with significant differences in NDI scores at 6 weeks and 3 months, and VAS neck pain and SF-12 PCS scores at 6 weeks (p<0.05). Operative level range of motion in the TDR group was maintained throughout follow-up. Radiographic evidence of inferior adjacent segment degeneration was significantly greater with ACDF at 12 and 24 months (p < 0.05). AE rates were similar.
Mobi-C TDR is a safe and effective treatment for single-level disc degeneration, producing outcomes similar to ACDF with less adjacent segment degeneration. Level of Evidence: Level I.
Clinical relevance: This study adds to the literature supporting cervical TDR as a viable option to ACDF in appropriately selected patients with disc degeneration.
PMCID: PMC4325486  PMID: 25694918
clinical outcome; randomized study; anterior cervical fusion; Cervical Spine; total disc replacement
8.  Dose-Dependent Metabolic Alterations in Human Cells Exposed to Gamma Irradiation 
PLoS ONE  2014;9(11):e113573.
Radiation exposure is a threat to public health because it causes many diseases, such as cancers and birth defects, due to genetic modification of cells. Compared with the past, a greater number of people are more frequently exposed to higher levels of radioactivity today, not least due to the increased use of diagnostic and therapeutic radiation-emitting devices. In this study, ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS)-based metabolic profiling was used to investigate radiation- induced metabolic changes in human fibroblasts. After exposure to 1 and 5 Gy of γ-radiation, the irradiated fibroblasts were harvested at 24, 48, and 72 h and subjected to global metabolite profiling analysis. Mass spectral peaks of cell extracts were analyzed by pattern recognition using principal component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA). The results showed that the cells irradiated with 1 Gy returned to control levels at 72 h post radiation, whereas cells irradiated with 5 Gy were quite unlike the controls; therefore, cells irradiated with 1 Gy had recovered, whereas those irradiated with 5 Gy had not. Lipid and amino acid levels increased after the higher-level radiation, indicating degradation of membranes and proteins. These results suggest that MS-based metabolite profiling of γ-radiation-exposed human cells provides insight into the global metabolic alterations in these cells.
PMCID: PMC4242643  PMID: 25419661
9.  Clinical characteristics and serum N-terminal pro-brain natriuretic peptide as a diagnostic marker of Kawasaki disease in infants younger than 3 months of age 
Korean Journal of Pediatrics  2014;57(8):357-362.
The incidence of Kawasaki disease (KD) is rare in young infants (less than 3 months of age), who present with only a few symptoms that fulfill the clinical diagnostic criteria. The diagnosis for KD can therefore be delayed, leading to a high risk of cardiac complications. We examined the clinical characteristics and measured the serum levels of N-terminal pro-brain natriuretic peptide (NT-proBNP) levels of these patients for assessing its value in the early detection of KD.
We retrospectively reviewed the data of young infants diagnosed with KD from 2004 to 2012. The control group included 20 hospitalized febrile patients. Laboratory data, including NT-proBNP were obtained for each patient in both groups.
Incomplete KD was observed in 21/24 patients (87.5%). The mean fever duration on admission was 1.36±1.0 days in the KD group. Common symptoms included erythema at the site of Bacille Calmette-Guerin inoculation (70.8%), skin rash (50.0%), changes of oropharyngeal mucosa (29.1%), and cervical lymphadenopathy (20.8%). The mean number of major diagnostic criteria fulfilled was 2.8±1.4. Five KD patients (20.8%) had only one symptom matching these criteria. The incidence of coronary artery complications was 12.5%. The mean serum NT-proBNP level in the acute phase, in the KD and control groups, were 4,159±3,714 pg/mL and 957±902 pg/mL, respectively, which decreased significantly in the convalescent phase.
Incomplete KD was observed in 87.5% patients. Serum NT-proBNP might be a valuable biomarker for the early detection of KD in febrile infants aged <3 months.
PMCID: PMC4155180  PMID: 25210523
Kawasaki disease; Infant; Brain natriuretic peptide
10.  Spatial analysis of PM10 and cardiovascular mortality in the Seoul metropolitan area 
Numerous studies have revealed the adverse health effects of acute and chronic exposure to particulate matter less than 10 μm in aerodynamic diameter (PM10). The aim of the present study was to examine the spatial distribution of PM10 concentrations and cardiovascular mortality and to investigate the spatial correlation between PM10 and cardiovascular mortality using spatial scan statistic (SaTScan) and a regression model.
From 2008 to 2010, the spatial distribution of PM10 in the Seoul metropolitan area was examined via kriging. In addition, a group of cardiovascular mortality cases was analyzed using SaTScan-based cluster exploration. Geographically weighted regression (GWR) was applied to investigate the correlation between PM10 concentrations and cardiovascular mortality.
An examination of the regional distribution of the cardiovascular mortality was higher in provincial districts (gu) belonging to Incheon and the northern part of Gyeonggido than in other regions. In a comparison of PM10 concentrations and mortality cluster (MC) regions, all those belonging to MC 1 and MC 2 were found to belong to particulate matter (PM) 1 and PM 2 with high concentrations of air pollutants. In addition, the GWR showed that PM10 has a statistically significant relation to cardiovascular mortality.
To investigate the relation between air pollution and health impact, spatial analyses can be utilized based on kriging, cluster exploration, and GWR for a more systematic and quantitative analysis. It has been proven that cardiovascular mortality is spatially related to the concentration of PM10.
PMCID: PMC4152940  PMID: 25116367
Cardiovascular mortality; Geographically weighted regression; PM10; SaTScan; Spatial epidemiology
12.  Gender-Specific Metabolomic Profiling of Obesity in Leptin-Deficient ob/ob Mice by 1H NMR Spectroscopy 
PLoS ONE  2013;8(10):e75998.
Despite the numerous metabolic studies on obesity, gender bias in obesity has rarely been investigated. Here, we report the metabolomic analysis of obesity by using leptin-deficient ob/ob mice based on the gender. Metabolomic analyses of urine and serum from ob/ob mice compared with those from C57BL/6J lean mice, based on the 1H NMR spectroscopy in combination with multivariate statistical analysis, revealed clear metabolic differences between obese and lean mice. We also identified 48 urine and 22 serum metabolites that were statistically significantly altered in obese mice compared to lean controls. These metabolites are involved in amino acid metabolism (leucine, alanine, ariginine, lysine, and methionine), tricarbocylic acid cycle and glucose metabolism (pyruvate, citrate, glycolate, acetoacetate, and acetone), lipid metabolism (cholesterol and carnitine), creatine metabolism (creatine and creatinine), and gut-microbiome-derived metabolism (choline, TMAO, hippurate, p-cresol, isobutyrate, 2-hydroxyisobutyrate, methylamine, and trigonelline). Notably, our metabolomic studies showed distinct gender variations. The obese male mice metabolism was specifically associated with insulin signaling, whereas the obese female mice metabolism was associated with lipid metabolism. Taken together, our study identifies the biomarker signature for obesity in ob/ob mice and provides biochemical insights into the metabolic alteration in obesity based on gender.
PMCID: PMC3789719  PMID: 24098417
13.  Pharmacological Activation of Sirt1 Ameliorates Polyglutamine-Induced Toxicity through the Regulation of Autophagy 
PLoS ONE  2013;8(6):e64953.
Intracellular accumulation of polyglutamine (polyQ)-expanded Huntingtin (Htt) protein is a hallmark of Huntington’s disease (HD). This study evaluated whether activation of Sirt1 by the anti-cancer agent, β-lapachone (β-lap), induces autophagy in human neuroblastoma SH-SY5Y cells, thereby reducing intracellular levels of polyQ aggregates and their concomitant cytotoxicity. Treatment of cells with β-lap markedly diminished the cytotoxicity induced by forced expression of Htt exon 1 containing a pathogenic polyQ stretch fused to green fluorescent protein (HttEx1(97Q)-GFP). β-lap increased autophagy in SH-SY5Y cells, as evidenced by the increased formation of LC3-II and autolysosomes. Furthermore, β-lap reduced HttEx1(97Q)-GFP aggregation, which was significantly prevented by co-incubation with 3-methyladenine, an inhibitor of autophagy. β-lap increased Sirt1 activity, as shown by the increased deacetylation of the Sirt1 substrates, PARP-1 and Atg5, and the nuclear translocation of FOXO1. Both the induction of autophagy and attenuation of HttEx1(97Q)-GFP aggregation by β-lap were significantly prevented by co-incubation with sirtinol, a general sirtuin inhibitor or by co-transfection with shRNA against Sirt1. The pro-autophagic actions of β-lap were further investigated in a transgenic Caenorhabditis elegans (C. elegans) line that expressed Q67 fused to cyanine fluorescent protein (Q67). Notably, β-lap reduced the number of Q67 puncta and restored Q67-induced defects in motility, which were largely prevented by pre-treatment with RNAi against sir-2.1, the C. elegans orthologue of Sirt1. Collectively, these data suggest that β-lap induces autophagy through activation of Sirt1, which in turn leads to a reduction in polyQ aggregation and cellular toxicity. Thus, β-lap provides a novel therapeutic opportunity for the treatment of HD.
PMCID: PMC3677867  PMID: 23762270
14.  Stevens-Johnson Syndrome Induced by Carbamazepine Treatment in a Patient Who Previously Had Carbamazepine Induced Pruritus - A Case Report - 
The Korean Journal of Pain  2013;26(1):80-83.
Stevens-Johnson syndrome (SJS) is a rare but life-threatening skin reaction disease and carbamazepine is one of its most common causes. We report a case of SJS secondary to carbamazepine in a patient with previous pruritus due to carbamazepine which was given for treatment of trigeminal neuralgia. We would like to caution all providers that carbamazepine readministration should be avoided in the patient with a previous history of SJS or adverse skin reaction. In addition, we strongly recommend gradual titration when initiating treatment with carbamazepine.
PMCID: PMC3546217  PMID: 23342214
carbamazepine; drug hypersensitivity reaction; Stevens-Johnson syndrome; trigerminal neuralgia
15.  Gene-Modified Adult Stem Cells Regenerate Vertebral Bone Defect in a Rat Model 
Molecular pharmaceutics  2011;8(5):1592-1601.
Vertebral compression fractures (VCFs), the most common fragility fractures, account for approximately 700,000 injuries per year. Since open surgery involves morbidity and implant failure in the osteoporotic patient population, new minimally invasive biological solution to vertebral bone repair is needed. Previously, we showed that adipose-derived stem cells (ASCs) overexpressing a BMP gene are capable of inducing spinal fusion in vivo. We hypothesized that a direct injection of ASCs, designed to transiently overexpress rhBMP6, into a vertebral bone void defect would accelerate bone regeneration. Porcine ASCs were isolated and labeled with lentiviral vectors that encode for the reporter gene luciferase (Luc) under constitutive (ubiquitin) or inductive (osteocalcin) promoters. The ASCs were first labeled with reporter genes and then nucleofected with an rhBMP6-encoding plasmid. Twenty-four hours later, bone void defects were created in the coccygeal vertebrae of nude rats. The ASC-BMP6 cells were suspended in fibrin gel (FG) and injected into the bone void. A control group was injected with FG alone. The regenerative process was monitored in vivo using microCT, and cell survival and differentiation were monitored using tissue specific reporter genes and bioluminescence imaging (BLI). The surgically treated vertebrae were harvested after 12 weeks and subjected to histological and immunohistochemical (against porcine vimentin) analyses. In vivo BLI detected Luc-expressing cells at the implantation site over a 12-week period. Beginning 2 weeks postoperatively, considerable defect repair was observed in the group treated with ASC-BMP6 cells. The rate of bone formation in the stem cell–treated group was two times faster than that in the FG–treated group, and bone volume at the endpoint was twofold compared to the control group. Twelve weeks after cell injection the bone volume within the void reached the volume measured in native vertebrae. Immunostaining against porcine vimentin indicated that the ASC-BMP6 cells contributed to new bone formation. Here we show the potential of injections of BMP-modified ASCs to repair vertebral bone defects in a rat model. Our results could pave the way to a novel approach for the biological treatment of traumatic and osteoporosis-related vertebral bone injuries.
PMCID: PMC3220930  PMID: 21834548
vertebral fracture; bone regeneration; gene-and-cell therapy; stem cell tracking
16.  DBC1 does not function as a negative regulator of SIRT1 in liver cancer 
Oncology Letters  2012;4(5):873-877.
The putative tumor suppressor, DBC1 (deleted in breast cancer-1), was recently found to negatively regulate SIRT1 in vitro and in vivo, but the mechanism whereby DBC1 regulates SIRT1 in liver cancer remains to be elucidated. In this study, it was found that although the expression of DBC1 and SIRT1 was not aberrantly regulated in a large cohort of human hepatocellular carcinoma (HCC) patients, these proteins were highly overexpressed in a subset of HCC tissues compared with surrounding non-cancer tissues. In liver cancer, DBC1 and SIRT1 were found to be positively correlated. Inactivation of DBC1 or SIRT1 reduced SNU-182 (a liver cancer cell line) proliferation as determined by MTT viability assays. Notably, although DBC1 functions as a negative regulator of SIRT1 in A549 lung cancer cells since it suppresses the deacetylase activity of the p53 protein, it did not affect the p53 deacetylase activity of SIRT1 in SNU-182 cells. Taken together, we conclude that DBC1 is associated with SIRT1 in HCC, but that it does not inhibit SIRT1.
PMCID: PMC3499483  PMID: 23162614
deleted in breast cancer-1; silent mating type information regulation 2 homolog 1; hepatocellular carcinoma; p53
17.  Anesthetic management of HELLP syndrome complicating primary antiphospholipid syndrome -A case report- 
Korean Journal of Anesthesiology  2012;62(6):575-578.
Antiphospholipid syndrome (APS) is defined as an autoimmune disorder characterized by recurrent thrombosis or obstetrical morbidity. A 29-year-old woman who was diagnosed with APS underwent emergency cesarean delivery at 23 weeks' gestation. She had a seizure attack and her laboratory findings were: AST/ALT 1459/1108 IU/L, LDH 1424 IU/L, 30% hematocrit, a platelet count of 43 × 103/ml and urine protein (4+). We describe the anesthetic experience of catastrophic HELLP syndrome with antiphospholipid syndrome and we review the relevant literature.
PMCID: PMC3384799  PMID: 22778897
Antiphospholipid syndrome; Eclampsia; HELLP
18.  Transglutaminase-2 Is Involved in All-Trans Retinoic Acid-Induced Invasion and Matrix Metalloproteinases Expression of SH-SY5Y Neuroblastoma Cells via NF-κB Pathway 
Biomolecules & Therapeutics  2012;20(3):286-292.
All-trans retinoic acid (ATRA) is currently used in adjuvant differentiation-based treatment of residual or relapsed neuroblastoma (NB). It has been reported that short-term ATRA treatment induces migration and invasion of SH-SY5Y via transglutaminase-2 (Tgase-2). However, the detailed mechanism of Tgase-2's involvement in NB cell invasion remains unclear. Therefore we investigated the role of Tgase-2 in invasion of NB cells using SH-SY5Y cells. ATRA dose-dependently induced the invasion of SH-SY5Y cells. Cystamine (CTM), a well known tgase inhibitor suppressed the ATRA-induced invasion of SH-SY5Y cells in a dose-dependent manner. Matrix metalloproteinase-9 (MMP-9) and MMP-2, well known genes involved in invasion of cancer cells were induced in the ATRA-induced invasion of the SH-SH5Y cells. Treatment of CTM suppressed the MMP-9 and MMP-2 enzyme activities in the ATRA-induced invasion of the SH-SY5Y cells. To confirm the involvement of Tgase-2, gene silencing of Tgase-2 was performed in the ATRA-induced invasion of the SH-SH5Y cells. The siRNA of Tgase-2 suppressed the MMP-9 and MMP-2 activity of the SH-SY5Y cells. MMP-2 and MMP-9 are well known target genes of NF-κB. Therefore the relationship of Tgase-2 and NF-κB in the ATRA-induced invasion of the SH-SY5Y cells was examined using siRNA and CTM. ATRA induced the activation of NF-κB in the SH-SY5Y cells and CTM suppressed the activation of NF-κB. Gene silencing of Tgase-2 suppressed the MMP expression by ATRA. These results suggested that Tgase-2 might be a new target for controlling the ATRA-induced invasion of NBs.
PMCID: PMC3794525  PMID: 24130925
All-trans retinoic acid; Transglutaminase-2; Invasion; Neuroblastoma; NF-κB; Matrix metalloproteinase
19.  HDAC1 Inactivation Induces Mitotic Defect and Caspase-Independent Autophagic Cell Death in Liver Cancer 
PLoS ONE  2012;7(4):e34265.
Histone deacetylases (HDACs) are known to play a central role in the regulation of several cellular properties interlinked with the development and progression of cancer. Recently, HDAC1 has been reported to be overexpressed in hepatocellular carcinoma (HCC), but its biological roles in hepatocarcinogenesis remain to be elucidated. In this study, we demonstrated overexpression of HDAC1 in a subset of human HCCs and liver cancer cell lines. HDAC1 inactivation resulted in regression of tumor cell growth and activation of caspase-independent autophagic cell death, via LC3B-II activation pathway in Hep3B cells. In cell cycle regulation, HDAC1 inactivation selectively induced both p21WAF1/Cip1 and p27Kip1 expressions, and simultaneously suppressed the expression of cyclin D1 and CDK2. Consequently, HDAC1 inactivation led to the hypophosphorylation of pRb in G1/S transition, and thereby inactivated E2F/DP1 transcription activity. In addition, we demonstrated that HDAC1 suppresses p21WAF1/Cip1 transcriptional activity through Sp1-binding sites in the p21WAF1/Cip1 promoter. Furthermore, sustained suppression of HDAC1 attenuated in vitro colony formation and in vivo tumor growth in a mouse xenograft model. Taken together, we suggest the aberrant regulation of HDAC1 in HCC and its epigenetic regulation of gene transcription of autophagy and cell cycle components. Overexpression of HDAC1 may play a pivotal role through the systemic regulation of mitotic effectors in the development of HCC, providing a particularly relevant potential target in cancer therapy.
PMCID: PMC3319574  PMID: 22496786
20.  Genetically Modified Mesenchymal Stem Cells Induce Mechanically Stable Posterior Spine Fusion 
Tissue Engineering. Part A  2010;16(12):3679-3686.
Most spine fusion procedures involve the use of prosthetic fixation devices combined with autologous bone grafts rather than biological treatment. We had shown that spine fusion could be achieved by injection of bone morphogenetic protein-2 (BMP-2)-expressing mesenchymal stem cells (MSCs) into the paraspinal muscle. In this study, we hypothesized that posterior spinal fusion achieved using genetically modified MSCs would be mechanically comparable to that realized using a mechanical fixation. BMP-2-expressing MSCs were injected bilaterally into paravertebral muscles of the mouse lumbar spine. In one control group BMP-2 expression was inhibited. Microcomputed tomography and histological analyses were used to evaluate bone formation. For comparison, a group of mouse spines were bilaterally fused with stainless steel pins. The harvested spines were later tested using a custom four-point bending apparatus and structural bending stiffness was estimated. To assess the degree to which MSC vertebral fusion was targeted and to quantify the effects of fusion on adjacent spinal segments, images of the loaded spine curvature were analyzed to extract rigidity of the individual spinal segments. Bone bridging of the targeted vertebrae was observed in the BMP-2-expressing MSC group, whereas no bone formation was noted in any control group. The biomechanical tests showed that MSC-mediated spinal fusion was as effective as stainless steel pin-based fusion and significantly more rigid than the control groups. Local analysis showed that the distribution of stiffness in the MSC-based fusion group was similar to that in the steel pin fusion group, with the majority of spinal stiffness contributed by the targeted fusion at L3–L5. Our findings demonstrate that MSC-induced spinal fusion can convey biomechanical rigidity to a targeted segment that is comparable to that achieved using an instrumental fixation.
PMCID: PMC2991214  PMID: 20618082
21.  Aberrant Regulation of HDAC2 Mediates Proliferation of Hepatocellular Carcinoma Cells by Deregulating Expression of G1/S Cell Cycle Proteins 
PLoS ONE  2011;6(11):e28103.
Histone deacetylase 2 (HDAC2) is crucial for embryonic development, affects cytokine signaling relevant for immune responses and is often significantly overexpressed in solid tumors; but little is known about its role in human hepatocellular carcinoma (HCC). In this study, we showed that targeted-disruption of HDAC2 resulted in reduction of both tumor cell growth and de novo DNA synthesis in Hep3B cells. We then demonstrated that HDAC2 regulated cell cycle and that disruption of HDAC2 caused G1/S arrest in cell cycle. In G1/S transition, targeted-disruption of HDAC2 selectively induced the expression of p16INK4A and p21WAF1/Cip1, and simultaneously suppressed the expression of cyclin D1, CDK4 and CDK2. Consequently, HDAC2 inhibition led to the down-regulation of E2F/DP1 target genes through a reduction in phosphorylation status of pRb protein. In addition, sustained suppression of HDAC2 attenuated in vitro colony formation and in vivo tumor growth in a mouse xenograft model. Further, we found that HDAC2 suppresses p21WAF1/Cip1 transcriptional activity via Sp1-binding site enriched proximal region of p21WAF1/Cip1 promoter. In conclusion, we suggest that the aberrant regulation of HDAC2 may play a pivotal role in the development of HCC through its regulation of cell cycle components at the transcription level providing HDAC2 as a relevant target in liver cancer therapy.
PMCID: PMC3223227  PMID: 22132221
22.  Protein induced by vitamin K absence or antagonist-II production is a strong predictive marker for extrahepatic metastases in early hepatocellular carcinoma: a prospective evaluation 
BMC Cancer  2011;11:435.
Clinicians often experience extrahepatic metastases associated with hepatocellular carcinoma (HCC), even if no evidence of intrahepatic recurrence after treatment is observed. We investigated the pretreatment predictors of extrahepatic metastases in HCC patients.
Patients diagnosed with HCC without evidence of extrahepatic metastases were prospectively enrolled. We evaluated the correlation between extrahepatic metastases and pretreatment clinical variables, including serum tumor markers.
A total of 354 patients were included. Seventy-six patients (21%) had extrahepatic metastases during the observation period (median, 25.3 months; range, 0.6-51.3 months). Cox regression multivariate analysis showed that serum protein induced by vitamin K absence or antagonist-II (PIVKA-II) production levels, the intrahepatic tumor stage, platelet count, and portal vein thrombosis were independent risk factors for extrahepatic metastases. Patients with a PIVKA-II production ≥ 300 mAU/mL had a 2.7-fold (95% confidence interval; 1.5-4.8; P < 0.001) and 3.7-fold (95% confidence interval; 2.0-6.6; P < 0.001) increased risk for extrahepatic metastases after adjustment for stage, platelet count, alpha-fetoprotein ≥ 400 ng/mL, and portal vein thrombosis according to the AJCC and BCLC staging systems, respectively.
PIVKA-II production levels might be a good candidate predictive marker for extrahepatic HCC metastases, especially in patients with smaller and/or fewer tumors in the liver with in stages regardless of serum alpha-fetoprotein.
PMCID: PMC3210108  PMID: 21985636
Protein induced by vitamin K absence or antagonist-II; hepatocellular carcinoma; metastases; predictive marker
23.  An Engineered Viral Protease Exhibiting Substrate Specificity for a Polyglutamine Stretch Prevents Polyglutamine-Induced Neuronal Cell Death 
PLoS ONE  2011;6(7):e22554.
Polyglutamine (polyQ)-induced protein aggregation is the hallmark of a group of neurodegenerative diseases, including Huntington's disease. We hypothesized that a protease that could cleave polyQ stretches would intervene in the initial events leading to pathogenesis in these diseases. To prove this concept, we aimed to generate a protease possessing substrate specificity for polyQ stretches.
Methodology/Principal Findings
Hepatitis A virus (HAV) 3C protease (3CP) was subjected to engineering using a yeast-based method known as the Genetic Assay for Site-specific Proteolysis (GASP). Analysis of the substrate specificity revealed that 3CP can cleave substrates containing glutamine at positions P5, P4, P3, P1, P2′, or P3′, but not substrates containing glutamine at the P2 or P1′ positions. To accommodate glutamine at P2 and P1′, key residues comprising the active sites of the S2 or S1′ pockets were separately randomized and screened. The resulting sets of variants were combined by shuffling and further subjected to two rounds of randomization and screening using a substrate containing glutamines from positions P5 through P3′. One of the selected variants (Var26) reduced the expression level and aggregation of a huntingtin exon1-GFP fusion protein containing a pathogenic polyQ stretch (HttEx1(97Q)-GFP) in the neuroblastoma cell line SH-SY5Y. Var26 also prevented cell death and caspase 3 activation induced by HttEx1(97Q)-GFP. These protective effects of Var26 were proteolytic activity-dependent.
These data provide a proof-of-concept that proteolytic cleavage of polyQ stretches could be an effective modality for the treatment of polyQ diseases.
PMCID: PMC3140514  PMID: 21799895
24.  Ectopic Expression of X-linked Lymphocyte-Regulated Protein pM1 (XLR) Renders Tumor Cells Resistant to Anti-Tumor Immunity 
Cancer research  2010;70(8):3062-3070.
Tumor immune escape is a major obstacle in cancer immunotherapy but the mechanisms involved remain poorly understood. We have previously developed an immune evasion tumor model using an in vivo immune selection strategy and revealed Akt-mediated immune resistance to anti-tumor immunity induced by various cancer immunotherapeutic agents. In the current study, we employed microarray gene analysis to identify an Akt-activating candidate molecule overexpressed in immune resistant tumors compared to parental tumors. X-linked lymphocyte-regulated protein pM1 (XLR) gene was the most upregulated in immune-resistant tumors compared to parental tumor cells. Furthermore, the retroviral transduction of XLR in parental tumor cells led to activation of Akt, resulting in upregulation of anti-apoptotic proteins and the induction of immune resistance phenotype in parental tumor cells. In addition, we found that transduction of parental tumor cells with other homologous genes from the mouse XLR family, such as synaptonemal complex protein 3 (SCP3) and XLR-related, meiosis regulated protein (XMR) and its human counterpart of SCP3 (hSCP3) also led to activation of Akt, resulting in the upregulation of anti-apoptotic proteins and induction of immune resistance phenotype. Importantly, characterization of a panel of human cervical cancers revealed relatively higher expression levels of hSCP3 in human cervical cancer tissue compared to normal cervical tissue. Thus, our data indicate that ectopic expression of XLR and its homologs in tumor cells represents a potentially important mechanism for tumor immune evasion and serves as a promising molecular target for cancer immunotherapy.
PMCID: PMC2861497  PMID: 20395201
XLR; Akt; immune resistance; human papillomavirus (HPV); E7
25.  Lifestyle, nutrient intake, iron status, and pregnancy outcome in pregnant women of advanced maternal age 
The purpose of this study was to investigate how advanced maternal age influences lifestyle, nutrient intake, iron status, and pregnancy outcomes in pregnant women. The subjects of this study were 112 pregnant women who were receiving prenatal care at gynecologists located in Seoul. The subjects were divided into two groups according to their ages: those over age 35 were the advanced age group of pregnant women (AP) and those under age 35 were the young age group of pregnant women (YP). General factors, nutrient intakes, iron status, and pregnancy outcomes of the two groups were then compared. It was found that 72.5% of the YP group and 51.2% of the AP group had pre-pregnancy alcohol drinking experience; indicating that the YP group had more pre-pregnancy alcohol consumption than the AP group (P < 0.05). The only difference found in nutrient intake between the two groups was their niacin intakes which were 16.83 ± 8.20 mg/day and 13.76 ± 5.28 mg/day, respectively. When gestational age was shorter than 38.7 weeks, the average infant birth weight was 2.95 ± 0.08 kg, and when gestational age was longer than 40 weeks, it averaged at about 3.42 ± 0.08 kg. In other words, as gestational age increased, infant birth weight increased (P < 0.0001), and when maternal weight increased more than 15 kg, the infant birth weight increased significantly (P < 0.05). In conclusion, in order to secure healthy human resources, with respect to advanced aged women, it is necessary to intervene by promoting daily habits that consist of strategic increases in folate and calcium intake along with appropriate amounts of exercise.
PMCID: PMC3061271  PMID: 21487497
Advanced aged pregnancy; intake; lifestyle; pregnancy outcome

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