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1.  Cross-reactivity to Acetaminophen and Celecoxib According to the Type of Nonsteroidal Anti-inflammatory Drug Hypersensitivity 
Identification of tolerable alternative analgesics is crucial for management in nonsteroidal anti-inflammatory drug (NSAID)-sensitive patients. We investigated cross-reactivity of acetaminophen and celecoxib according to the type of aspirin/NSAID hypersensitivity and aimed to determine the risk factors for cross-intolerance.
We retrospectively reviewed the medical records of patients intolerant to aspirin and NSAIDs who had undergone an acetaminophen and/or celecoxib oral provocation test. Aspirin/NSAID hypersensitivity was classified into 4 types according to a recently proposed classification: aspirin-exacerbated respiratory disease (AERD), aspirin-exacerbated chronic urticaria (AECU), aspirin-induced acute urticaria/angioedema (AIAU), and NSAID-induced blended reaction (NIRD).
A total of 180 patients with hypersensitivity to aspirin and NSAIDs were enrolled; 149 acetaminophen provocation test results and 145 celecoxib provocation test results were analyzed. The overall cross-reaction rates to acetaminophen and celecoxib were 24.8% and 10.3%, respectively. There was a significant difference in the cross-reactivity to acetaminophen according to the type of NSAID hypersensitivity. Cross-reactivity to acetaminophen was highest in the AECU group (43.9%), followed by the AERD (33.3%), NIBR (16.7%), and AIAU (12.5%) groups. Underlying chronic urticaria was more prevalent in patients with cross-intolerance to both acetaminophen (P=0.001) and celecoxib (P=0.033). Intolerance to acetaminophen was associated with intolerance to celecoxib (P<0.001).
Acetaminophen and celecoxib may induce adverse reactions in a non-negligible portion of aspirin/NSAID-sensitive patients. Physicians should be aware of the possible cross-reactions of these alternative drugs and consider an oral challenge test to confirm their tolerability.
PMCID: PMC3936045  PMID: 24587953
Acetaminophen; celecoxib; cross reactions; hypersensitivity; intolerance; anti-inflammatory agents; non-steroidal
4.  Polymer-Ceramic Spiral Structured Scaffolds for Bone Tissue Engineering: Effect of Hydroxyapatite Composition on Human Fetal Osteoblasts 
PLoS ONE  2014;9(1):e85871.
For successful bone tissue engineering, a scaffold needs to be osteoconductive, porous, and biodegradable, thus able to support attachment and proliferation of bone cells and guide bone formation. Recently, hydroxyapatites (HA), a major inorganic component of natural bone, and biodegrade polymers have drawn much attention as bone scaffolds. The present study was designed to investigate whether the bone regenerative properties of nano-HA/polycaprolactone (PCL) spiral scaffolds are augmented in an HA dose dependent manner, thereby establishing a suitable composition as a bone formation material. Nano-HA/PCL spiral scaffolds were prepared with different weight ratios of HA and PCL, while porosity was introduced by a modified salt leaching technique. Human fetal osteoblasts (hFOBs) were cultured on the nano-HA/PCL spiral scaffolds up to 14 days. Cellular responses in terms of cell adhesion, viability, proliferation, differentiation, and the expression of bone-related genes were investigated. These scaffolds supported hFOBs adhesion, viability and proliferation. Cell proliferation trend was quite similar on polymer-ceramic and neat polymer spiral scaffolds on days 1, 7, and 14. However, the significantly increased amount of alkaline phosphatase (ALP) activity and mineralized matrix synthesis was evident on the nano-HA/PCL spiral scaffolds. The HA composition in the scaffolds showed a significant effect on ALP and mineralization. Bone phenotypic markers such as bone sialoprotein (BSP), osteonectin (ON), osteocalcin (OC), and type I collagen (Col-1) were semi-quantitatively estimated by reverse transcriptase polymerase chain reaction analysis. All of these results suggested the osteoconductive characteristics of HA/PCL nanocomposite and cell maturation were HA dose dependent. For instance, HA∶PCL = 1∶4 group showed significantly higher ALP mineralization and elevated levels of BSP, ON, OC and Col-I expression as compared other lower or higher ceramic ratios. Amongst the different nano-HA/PCL spiral scaffolds, the 1∶4 weight ratio of HA and PCL is shown to be the most optimal composition for bone tissue regeneration.
PMCID: PMC3903490  PMID: 24475056
5.  Perturbation of mitiglinide metabolism by chronic unpredicted mild stress in rats 
Scientific Reports  2014;4:3794.
Many diabetic patients complicated with wild to severe depression. It is unclear in diabetic medication whether depression perturbs the drug metabolic process of the hypoglycemic agents or not. The present study was designed to investigate the impact of chronic unpredicted mild stress (CUMS) –induced depression on mitiglinide (MGN) pharmacokinetics in rats. Adult female Sprague-Dawley rats in CUMS group were subjected to different types of stressors and the stress procedures lasted for 8 weeks. Control group without receiving stress had free access to food and water. Open-field test and 5-HT levels were assayed to evaluate the depression. After CUMS all rats were given 2.5 mg/kg of mitiglinide per os. The blood samples were collected at different time and mitiglinide plasma concentration was measured by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Non-compartmental statistical moment analysis was processed with DAS software. In CMUS-induced depression group, peak concentration (Cmax), peak time (Tmax), area under curve (AUC0 → ∞), mean residence time (MRT0 → ∞), and half-life (T1/2z) were reduced while total plasma clearance (CLz/F) was increased compared to control group. These preliminary results indicated that CUMS-induced depression alter the drug metabolic process of mitiglinide in rats. This finding will be significant in clinic.
PMCID: PMC3896903  PMID: 24445843
6.  Congenital sucrase-isomaltase deficiency: an under-diagnosed disease in Chinese children 
BMC Pediatrics  2014;14:11.
Congenital sucrase-isomaltase deficiency (CSID) is a rare genetic disorder. The prevalence of CSID in Chinese population is unknown and no single case has been reported.
Sucrose tolerance tests were performed in three children suspected of CSID. Glucose tolerance tests were performed to exclude glucose malabsorption. Blood glucose was measured at fasting and at 30 min, 60 min, 120 min, and 180 min of the study. Gastrointestinal symptoms were recorded up to 4 hours after the study.
From December 2008 to June 2011, three children, ranging from 16 to 19 months old, were referred to our tertiary children’s hospital due to chronic watery diarrhea and failure to thrive. Laboratory investigations including complete blood counts, ESR, CRP, and serum immunoglobulins were normal. Routine stool culture for bacteria and exam for parasites were negative. Upper endoscopy, colonoscopy and histology were unremarkable. All children failed lactose-free and amino acid-based formulas. All three children had flat sucrose tolerance tests and began to have watery stool 2–4 hours after feeding sucrose test solution. The glucose tolerance tests were normal and no children developed watery stools up to 4 hours after feeding glucose test solution.
This is the first case series of CSID in Chinese children. The diagnosis of CSID can be made based on clinical suspicion and sucrose tolerance test. CSID is probably an under-diagnosed or misdiagnosed disease in Chinese children and should be considered in children with chronic watery diarrhea.
PMCID: PMC3927221  PMID: 24433566
Sucrase-isomaltase deficiency; Chinese children; Sucrose tolerance test
7.  Mucinous metaplasia in urothelial tract may be the precancerous lesion of mucinous adenocarcinoma: report of two cases and review of literature 
Primary mucinous lesions of the urinary system are extremely rare. We describe two cases of primary mucinous lesions of the urothelial tract. One case is of mucinous metaplasia in the bladder of a 40-year-old man presenting with frequent urination, urgency, and gross hematuria. The other case is of mucinous adenocarcinoma in the pelvis of an otherwise healthy 67-year-old man with left nephrolithiasis. The histological images of the two cases demonstrate a spectrum from benign mucinous metaplasia to malignant mucinous adenocarcinoma, and suggest that mucinous metaplasia in urothelial tract may be the precancerous lesion of mucinous adenocarcinoma.
PMCID: PMC3902270  PMID: 24482718
Mucinous metaplasia; urothelium; precancerous lesion
8.  Gated F-18 FDG PET for Assessment of Left Ventricular Volumes and Ejection Fraction Using QGS and 4D-MSPECT in Patients with Heart Failure: A Comparison with Cardiac MRI 
PLoS ONE  2014;9(1):e80227.
Ventricular function is a powerful predictor of survival in patients with heart failure (HF). However, studies characterizing gated F-18 FDG PET for the assessment of the cardiac function are rare. The aim of this study was to prospectively compare gated F-18 FDG PET and cardiac MRI for the assessment of ventricular volume and ejection fraction (EF) in patients with HF.
Eighty-nine patients with diagnosed HF who underwent both gated F-18 FDG PET/CT and cardiac MRI within 3 days were included in the analysis. Left ventricular (LV) end-diastolic volume (EDV), end-systolic volume (ESV), and EF were obtained from gated F-18 FDG PET/CT using the Quantitative Gated SPECT (QGS) and 4D-MSPECT software.
LV EDV and LV ESV measured by QGS were significantly lower than those measured by cardiac MRI (both P<0.0001). In contrast, the corresponding values for LV EDV for 4D-MSPECT were comparable, and LV ESV was underestimated with borderline significance compared with cardiac MRI (P = 0.047). LV EF measured by QGS and cardiac MRI showed no significant differences, whereas the corresponding values for 4D-MSPECT were lower than for cardiac MRI (P<0.0001). The correlations of LV EDV, LV ESV, and LV EF between gated F-18 FDG PET/CT and cardiac MRI were excellent for both QGS (r = 0.92, 0.92, and 0.76, respectively) and 4D-MSPECT (r = 0.93, 0.94, and 0.75, respectively). However, Bland-Altman analysis revealed a significant systemic error, where LV EDV (−27.9±37.0 mL) and ESV (−18.6±33.8 mL) were underestimated by QGS.
Despite the observation that gated F-18 FDG PET/CT were well correlated with cardiac MRI for assessing LV function, variation was observed between the two imaging modalities, and so these imaging techniques should not be used interchangeably.
PMCID: PMC3880258  PMID: 24404123
9.  Hypothermia-induced acute kidney injury in an elderly patient 
Hypothermia, defined as an unintentional decline in the core body temperature to below 35℃, is a life-threatening condition. Patients with malnutrition and diabetes mellitus as well as those of advanced age are at high risk for accidental hypothermia. Due to the high mortality rates of accidental hypothermia, proper management is critical for the wellbeing of patients. Accidental hypothermia was reported to be associated with acute kidney injury (AKI) in over 40% of cases. Although the pathogenesis remains to be elucidated, vasoconstriction and ischemia in the kidney were considered to be the main mechanisms involved. Cases of AKI associated with hypothermia have been reported worldwide, but there have been few reports of hypothermia-induced AKI in Korea. Here, we present a case of hypothermia-induced AKI that was treated successfully with rewarming and supportive care.
PMCID: PMC3932381  PMID: 24574841
Hypothermia; Acute kidney injury; Rewarming; Vasoconstriction; Ischemia
10.  Sarcoplasmic Phospholamban Protein Is Involved in the Mechanisms of Postresuscitation Myocardial Dysfunction and the Cardioprotective Effect of Nitrite during Resuscitation 
PLoS ONE  2013;8(12):e82552.
Sarcoplasmic reticulum (SR) Ca2+-handling proteins play an important role in myocardial dysfunction after acute ischemia/reperfusion injury. We hypothesized that nitrite would improve postresuscitation myocardial dysfunction by increasing nitric oxide (NO) generation and that the mechanism of this protection is related to the modulation of SR Ca2+-handling proteins.
We conducted a randomized prospective animal study using male Sprague-Dawley rats. Cardiac arrest was induced by intravenous bolus of potassium chloride (40 µg/g). Nitrite (1.2 nmol/g) or placebo was administered when chest compression was started. No cardiac arrest was induced in the sham group. Hemodynamic parameters were monitored invasively for 90 minutes after the return of spontaneous circulation (ROSC). Echocardiogram was performed to evaluate cardiac function. Myocardial samples were harvested 5 minutes and 1 hour after ROSC.
Myocardial function was significantly impaired in the nitrite and placebo groups after resuscitation, whereas cardiac function (i.e., ejection fraction and fractional shortening) was significantly greater in the nitrite group than in the placebo group. Nitrite administration increased the level of nitric oxide in the myocardium 5 min after resuscitation compared to the other two groups. The levels of phosphorylated phospholamban (PLB) were decreased after resuscitation, and nitrite increased the phosphorylation of phospholamban compared to the placebo. No significant differences were found in the expression of sarcoplasmic reticulum Ca2+ ATPase (SERCA2a) and ryanodine receptors (RyRs).
postresuscitation myocardial dysfunction is associated with the impairment of PLB phosphorylation. Nitrite administered during resuscitation improves postresuscitation myocardial dysfunction by preserving phosphorylated PLB protein during resuscitation.
PMCID: PMC3875413  PMID: 24386101
11.  Elevated MicroRNA-31 Expression Regulates Colorectal Cancer Progression by Repressing Its Target Gene SATB2 
PLoS ONE  2013;8(12):e85353.
Several studies have brought about increasing evidence to support the hypothesis that miRNAs play a pivotal role in multiple processes of carcinogenesis, including cell growth, apoptosis, differentiation, and metastasis. In this study, we investigated the potential role of miR-31 in colorectal cancer (CRC) aggressiveness and its underlying mechanisms. We found that miR-31 increased in CRC cells originated from metastatic foci and human primary CRC tissues with lymph node metastases. Furthermore, the high-level expression of miR-31 was significantly associated with a more aggressive and poor prognostic phenotype of patients with CRC (p < 0.05). The stable over-expression of miR-31 in CRC cells was sufficient to promote cell proliferation, invasion, and migration in vitro. It facilitated tumor growth and metastasis in vivo too. Further studies showed that miR-31 can directly bind to the 3’untranslated region (3’UTR) of SATB2 mRNA and subsequently repress both the mRNA and protein expressions of SATB2. Ectopic expression of SATB2 by transiently transfected with pCAG-SATB2 vector encoding the entire SATB2 coding sequence could reverse the effects of miR-31 on CRC tumorigenesis and progression. In addition, ectopic over-expression of miR-31 in CRC cells induced epithelial-mesenchymal transition (EMT). Our results illustrated that the up-regulation of miR-31 played an important role in CRC cell proliferation, invasion, and metastasis in vitro and in vivo through direct repressing SATB2, suggesting a potential application of miR-31 in prognosis prediction and therapeutic application in CRC.
PMCID: PMC3875556  PMID: 24386467
12.  A Highly Robust, Recyclable Displacement Assay for Mercuric Ions in Aqueous Solutions and Living Cells 
ACS nano  2012;6(12):10999-11008.
We designed a recyclable Hg2+ probe based on Rhodamine B isothiocyanate (RBITC) - poly (ethylene glycol) (PEG)-co-modified gold nanoparticles (AuNPs) with excellent robustness, selectivity and sensitivity. Based on a rational design, only Hg2+ can displace RBITC from the AuNP surfaces, resulting in a remarkable enhancement of RBITC fluorescence initially quenched by AuNPs. To maintain stability and monodispersity of AuNPs in real samples, thiol-terminated PEG was employed to bind with the remaining active sites of AuNPs. Besides, this displacement assay can be regenerated by resupplying free RBITC into the AuNPs solutions that were already used for detecting Hg2+. Importantly, the detection limit of this assay for Hg2+ (2.3 nM) was lower than the maximum limits guided by the United States Environmental Protection Agency as well as that permitted by the World Health Organization. The efficiency of this probe was demonstrated in monitoring Hg2+ in complex samples such as river water and living cells.
PMCID: PMC3528810  PMID: 23121626
gold nanoparticles; sensitivity; selectivity; recyclable detection; Rhodamine B isothiocyanate
13.  Evaluation of Chemotherapy Response in VX2 Rabbit Lung Cancer with 18F-Labeled C2A Domain of Synaptotagmin I 
The C2A domain of synaptotagmin I can target apoptotic cells by binding to exposed anionic phospholipids. The goal of this study was to synthesize and develop 18F-labeled C2A-gluta-thione-S-transferase (GST) as a molecular imaging probe for the detection of apoptosis and to assess the response of paclitaxel chemotherapy in VX2 rabbit lung cancer.
18F-C2A-GST was prepared by labeling C2A-GST with N-succinimidyl 4-18F-fluorobenzoate (18F-SFB). 18F-C2A-GST was confirmed by high-performance liquid chromatography and sodium dodecyl sulfate polyacrylamide gel electrophoresis. The binding of 18F-C2A-GST toward apoptosis was validated in vitro using camptothecin-induced Jurkat cells. Biodistribution of 18F-C2A-GST was determined in mice by a dissection method and small-animal PET. Single-dose paclitaxel was used to induce apoptosis in rabbits bearing VX2 tumors (n = 6), and 2 VX2 rabbits without treatment served as control. 18F-C2A-GST PET was performed before and at 72 h after therapy, and 18F-FDG PET/CT was also performed before treatment. To confirm the presence of apoptosis, tumor tissue was analyzed and activated caspase-3 was measured.
18F-C2A-GST was obtained with more than 95% radiochemical purity and was stable for 4 h after formulation. 18F-C2A-GST bound apoptotic cells specifically. Biodistribution in mice showed that 18F-C2A-GST mainly excreted from the kidneys and rapidly cleared from blood and nonspecific organs. High focal uptake of 18F-C2A-GST in the tumor area was determined after therapy, whereas no significant uptake before therapy was found in the tumor with 18F-FDG–avid foci. The maximum standardized uptake value after therapy was 0.47 ± 0.28, significantly higher than that in the control (0.009 ± 0.001; P < 0.001). The apoptotic index was 79.81% ± 8.73% in the therapy group, significantly higher than that in the control (5.03% ± 0.81%; P < 0.001). Activated caspase-3 after paclitaxel treatment increased to 69.55% ± 16.27% and was significantly higher than that in the control (12.26% ± 5.39%; P < 0.001).
18F-C2A-GST was easily synthesized by conjugation with 18F-SFB and manifested a favorable biodistribution. Our results demonstrated the feasibility of 18F-C2A-GST for the early detection of apoptosis after chemotherapy in a VX2 lung cancer model that could imitate the human lung cancer initiation, development, and progress.
PMCID: PMC3866918  PMID: 21421722
C2A domain; 18F-labeled C2A-GST; PET; apoptosis; synaptotagmin I
14.  Expression and Methylation of Mitochondrial Transcription Factor A in Chronic Obstructive Pulmonary Disease Patients with Lung Cancer 
PLoS ONE  2013;8(12):e82739.
Apoptosis plays a central role in the pathogenesis of chronic obstructive pulmonary disease (COPD), and this process can be regulated by mitochondrial transcription factor A (mtTFA). Epigenetics is involved in the regulation and modification of the genes involved in lung cancer and COPD. In this study, we determined the expression of mtTFA and its methylation levels in the COPD patients with lung cancer.
Twenty-one squamous cell lung cancer patients, 11 with COPD and 10 without COPD, undergoing pneumonectomy were enrolled. The apoptotic index (AI) of pulmonary vascular endothelial cells was analyzed by transferase-mediated deoxyuridine triphosphate-biotin nick end labeling assay. The expression of mtTFA mRNA and protein was measured using PCR, immunohistochemistry and Western-blot. Methylation of the mtTFA promoter was detected using bisulfite sequencing PCR.
Compared to the non-COPD group, the AI was higher, and expression of mtTFA mRNA and protein was lower in the COPD group (P<0.001). Expression of the mtTFA protein was positively correlated with FEV1/Pre (r = 0.892, P<0.001), and negatively correlated with AI (r = −0.749, P<0.001) and smoke index (r = −0.763, P<0.001). Percentage of mtTFA promoter methylation in the COPD patients was significantly higher compared to the non-COPD patients (P<0.05).
These results suggest that the expression of mtTFA mRNA and protein is down-regulated in the lung tissue from the COPD patients with squamous cell lung cancer, and the level of mtTFA protein is related to apoptosis of pulmonary vascular endothelial cells. Aberrant mtTFA methylation may also play an important role in the pathogenesis of COPD.
PMCID: PMC3867397  PMID: 24367550
15.  Endoscopic papillary large balloon dilation for the removal of bile duct stones 
Endoscopic papillary large balloon dilation (EPLBD) with endoscopic sphincterotomy (EST) has been widely used as the alternative to EST along with endoscopic mechanical lithotripsy (EML) for the removal of large or difficult bile duct stones. Furthermore, EPLBD without EST was recently introduced as its simplified alternative technique. Thus, we systematically searched PubMed, Medline, the Cochrane Library and EMBASE, and analyzed all gathered data of EPLBD with and without EST, respectively, by using a single standardized definition, reviewing relevant literatures, published between 2003 and June 2013, where it was performed with large-diameter balloons (12-20 mm). The outcomes, including the initial success rate, the rate of needs for EML, and the overall success rate, and adverse events were assessed in each and compared between both of two procedures: “EPLBD with EST” and “EPLBD without EST”. A total of 2511 procedures from 30 published articles were included in EPLBD with EST, while a total of 413 procedures from 3 published articles were included in EPLBD without EST. In the results of outcomes, the overall success rate was 96.5% in EPLBD with EST and 97.2% in EPLBD without EST, showing no significant difference between both of them. The initial success rate (84.0% vs 76.2%, P < 0.001) and the success rate of EPLBD without EML (83.2% vs 76.7%, P = 0.001) was significantly higher, while the rate of use of EML was significantly lower (14.1% vs 21.6%, P < 0.001), in EPLBD with EST. The rate of overall adverse events, pancreatitis, bleeding, perforation, other adverse events, surgery for adverse events, and fatal adverse events were 8.3%, 2.4%, 3.6%, 0.6%, 1.7%, 0.2% and 0.2% in EPLBD with EST and 7.0%, 3.9%, 1.9%, 0.5%, 0.7%, 0% and 0% in EPLBD without EST, respectively, showing no significant difference between both of them. In conclusion, recent accumulated results of EPLBD with or even without EST suggest that it is a safe and effective procedure for the removal of large or difficult bile duct stones without any additional risk of severe adverse events, when performed under appropriate guidelines.
PMCID: PMC3870503  PMID: 24379575
Balloon dilation; Endoscopic sphincterotomy; Common bile duct gallstones; Lithotripsy; Complications; Assessment; Patient outcomes
16.  Noninvasive positive pressure ventilation for the treatment of acute respiratory distress syndrome following esophagectomy for esophageal cancer: a clinical comparative study 
Journal of Thoracic Disease  2013;5(6):777-782.
To evaluate the therapeutic efficacy of noninvasive positive pressure ventilation (NPPV) in the treatment of acute respiratory distress syndrome (ARDS) following esophagectomy for esophageal cancer.
In this retrospective evaluation, we included 64 patients with ARDS following esophagectomy for esophageal cancer between January 2009 and December 2011. The primary evaluations were 28-day fatality and actual fatality. The secondary evaluations were sex, age, onset time, pH value, PaO2/FiO2, sequential organ failure assessment (SOFA) score, acute physiology and chronic health evaluation (APACHE-II) score, and presence or absence after surgery of major surgery-related complications such as cardiac arrest, anastomotic fistula, and acute renal dysfunction.
NPPV applied as the first-line intervention for ARDS following esophagectomy for esophageal cancer avoided intubation in 30 patients (30/64, 48.4%). There were no significant differences in gender, age, PaO2/FiO2, SOFA score, or APACHE-II score between the NPPV group and the patients who required invasive positive pressure ventilation (IPPV group) (P>0.05) at the time of onset, while differences in the PaO2/FiO2 (P<0.05) after 24 h of NPPV and presence of major surgery-related complications were highly significant (P<0.01).
NPPV may be an effective option for the treatment of ARDS/acute lung injury (ALI) following esophagectomy for esophageal cancer. However, conversion to invasive mechanical ventilation should be considered in patients with severe postoperative complications such as acute renal dysfunction and cardiac arrest and in those with PaO2/FiO2 <180 after 2 h of NPPV.
PMCID: PMC3886700  PMID: 24409355
Noninvasive positive pressure ventilation (NPPV); esophagectomy; acute respiratory distress syndrome (ARDS)
17.  Structural Insights into the Mechanism for Recognizing Substrate of the Cytochrome P450 Enzyme TxtE 
PLoS ONE  2013;8(11):e81526.
Thaxtomins, a family of phytotoxins produced by Streptomyces spp., can cause dramatic plant cell hypertrophy and seedling stunting. Thaxtomin A is the dominant form from Streptomyces scabies and has demonstrated herbicidal action. TxtE, a cytochrome P450 enzyme from Streptomyces scabies 87.22, catalyzes direct nitration of the indolyl moiety of L-tryptophan to L-4-nitrotryptophan using nitric oxide, dioxygen and NADPH. The crystal structure of TxtE was determined at 2.1 Å resolution and described in this work. A clearly defined substrate access channel is observed and can be classified as channel 2a, which is common in bacteria cytochrome P450 enzymes. A continuous hydrogen bond chain from the active site to the external solvent is observed. Compared with other cytochrome P450 enzymes, TxtE shows a unique proton transfer pathway which crosses the helix I distortion. Polar contacts of Arg59, Tyr89, Asn293, Thr296, and Glu394 with L-tryptophan are seen using molecular docking analysis, which are potentially important for substrate recognition and binding. After mutating Arg59, Asn293, Thr296 or Glu394 to leucine, the substrate binding ability of TxtE was lost or decreased significantly. Based on the docking and mutation results, a possible mechanism for substrate recognition and binding is proposed.
PMCID: PMC3840065  PMID: 24282603
18.  Visible-Light-Driven Oxidation of Primary C–H Bonds over CdS with Dual Co-catalysts Graphene and TiO2 
Scientific Reports  2013;3:3314.
Selective activation of primary C–H bonds for fine chemicals synthesis is of crucial importance for the sustainable exploitation of available feedstocks. Here, we report a viable strategy to synthesize ternary GR-CdS-TiO2 composites with an intimate spatial integration and sheet-like structure, which is afforded by assembling two co-catalysts, graphene and TiO2, into the semiconductor CdS matrix with specific morphology as a visible light harvester. The GR-CdS-TiO2 composites are able to serve as a highly selective visible-light-driven photocatalyst for oxidation of saturated primary C–H bonds using benign oxygen as oxidant under ambient conditions. This work demonstrates a wide, promising scope of adopting co-catalyst strategy to design more efficient semiconductor-based photocatalyst toward selective activation of C–H bonds using solar light and molecular oxygen.
PMCID: PMC3837378  PMID: 24264835
19.  Significance of thymidylate synthase expression for resistance to pemetrexed in pulmonary adenocarcinoma 
Oncology Letters  2013;7(1):227-232.
Pemetrexed (PEM), a multi-targeted antifolate, has promising clinical activity in non-squamous non-small cell lung cancer. However, the majority of patients eventually acquire resistance to PEM. To evaluate the resistant mechanisms, the A549 lung adenocarcinoma cell line was exposed to stepwise increasing PEM concentrations of 1.6, 6.4 and 16 μM to establish three PEM-resistant lung cancer cell lines, A549/PEM-1.6, -6.4 and -16. Growth inhibition was determined by the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assay. Expression of the genes encoding thymidylate synthase (TS), reduced folate carrier (RFC) and folypoly-γ-glutamate synthetase (FPGS) were analyzed by quantitative real-time reverse transcription polymerase chain reaction. The three A549 cell lines showed more resistance to PEM (3.7-, 17.3− and 38.0-fold, respectively) compared with that of the parental cell line, which also showed cross-resistance to cisplatin, but not to docetaxel, vinorelbine and 5-Fluorouracil (5-FU). TS gene expression was significantly increased in three PEM-resistant cells, relative to that of the parental cells, in a PEM dose-dependent manner. Knockdown of TS expression with siRNA enhanced the cytotoxicity of PEM in A549/PEM-16 cells. By contrast, the levels of RFC and FPGS gene expression in A549/PEM-1.6 and -6.4 cells were significantly decreased, whereas the levels of the two genes were restored in A549/PEM-16 cells. In summary, PEM-resistant A549 cells remained sensitive to docetaxel, vinorelbine and 5-FU. TS expression appeared to be associated with resistance to PEM, which may be a predictive marker for PEM sensitivity in lung adenocarcinoma.
PMCID: PMC3861605  PMID: 24348854
non-small cell lung cancer; pemetrexed; resistance; thymidylate synthase; reduced folate carrier; folypoly-γ-glutamate synthetase
20.  Overexpression of a LAM Domain Containing RNA-Binding Protein LARP1c Induces Precocious Leaf Senescence in Arabidopsis 
Molecules and Cells  2012;34(4):367-374.
Leaf senescence is the final stage of leaf life history, and it can be regulated by multiple internal and external cues. La-related proteins (LARPs), which contain a well-conserved La motif (LAM) domain and normally a canonical RNA recognition motif (RRM) or noncanonical RRM-like motif, are widely present in eukaryotes. Six LARP genes (LARP1a-1c and LARP6a-6c) are present in Arabidopsis, but their biological functions have not been studied previously. In this study, we investigated the biological roles of LARP1c from the LARP1 family. Constitutive or inducible overexpression of LARP1c caused premature leaf senescence. Expression levels of several senescence-associated genes and defense-related genes were elevated upon overexpression of LARP1c. The LARP1c null mutant 1c-1 impaired ABA-, SA-, and MeJA-induced leaf senescence in detached leaves. Gene expression profiles of LARP1c showed age-dependent expression in rosette leaves. Taken together, our results suggest LARP1c is involved in regulation of leaf senescence.
PMCID: PMC3887763  PMID: 22965746
Arabidopsis; LARP1c; senescence; senescence-associated genes
21.  Violence, mental health and violence risk factors among women in the general population: an0020epidemiology study based on two national household surveys in the UK 
BMC Public Health  2013;13:1020.
Females who perpetrated violence in the community have important mental health and public protection implications. There is a dearth of research in this area. This study investigated the prevalence of psychiatric morbidity, personality disorders as well as victim characteristics and violence risk factors of women in the community who self-reported violence against others.
The study sample consisted of 8,275 community women aged 16–74 years obtained from the 2000 and 2007 UK national psychiatric morbidity surveys. Self report incidences of violence, personality disorders and the presence of psychiatric symptoms were assessed by interviews and/or established structured psychiatric assessment protocols.
Weighted prevalence of female violence, which primarily involved partners and friends, was 5.5% in 2000 and 5.1% in 2007. Violence-prone women also had significantly higher prevalence of common mental disorders and comorbidity (adjusted odds ratio 3.3 and 2.9 respectively) than non-violent women. Multivariate analyses identified eight significant risk factors that characterized violence prone women: young age, residing in social-assisted housing, presence of early conduct problems, victim of domestic violence, self-harming, excessive drinking and past criminal justice involvements.
A higher prevalence of common mental disorders and some types of personality disorder was found among violence prone women compared to their non-violence prone counterparts. The identified violence risk factors could be used to develop a quick and easily administered rating tool suitable for use by non-mental health trained frontline workers such as police and social support workers in the community to identify violence-prone women. Mental health and support services then can be provided to them for mental health care and violence prevention purposes.
PMCID: PMC3829658  PMID: 24165544
Female violence; Mental disorders; Risk factors; Community samples; UK
22.  Genomic estimates of aneuploid content in Glioblastoma Multiforme and improved classification 
Accurate classification of Glioblastoma Multiforme (GBM) is crucial for understanding its biological diversity, and informing diagnosis and treatment. The Cancer Genome Atlas (TCGA) project identified four GBM classes using gene expression data, and separately, identified three classes using methylation data. We sought to integrate multiple data types in GBM classification, understand biological features of the newly defined subtypes, and reconcile with prior studies.
Experimental procedure
We used allele-specific copy number data to estimate the aneuploid content of each tumor, and incorporated this measure of intratumor heterogeneity in class discovery. We estimated the potential cell of origin of individual subtypes and the euploid and aneuploid fractions using reference datasets of known neuronal cell types.
There exists an unexpected correlation between aneuploid content and the observed among-tumor diversity of expression patterns. Joint use of DNA and mRNA data in ab initio class discovery revealed a distinct group that resembles the Proneural subtype described in a separate study and the G-CIMP+ class based on methylation data. Three additional subtypes, Classical, Proliferative, and Mesenchymal, were also identified, and revised the assignment for many samples. The revision showed stronger differences in patient outcome and clearer cell type-specific signatures. Mesenchymal GBMs had higher euploid content, potentially contributed by microglia/macrophage infiltration.
We clarified the confusion regarding the "Proneural" subtype that was defined differently in different prior studies. The ability to infer within-tumor heterogeneity improved class discovery, leading to new subtypes that are closer to the fundamental biology of GBM.
PMCID: PMC3477792  PMID: 22912392
GBM; classification; aneuploid content; survival time; data integration
23.  Basic anatomy and tumor biology of the RPS6KA6 gene that encodes the p90 ribosomal S6 kinase-4 
Oncogene  2012;32(14):1794-1810.
The RPS6KA6 gene encodes the p90 ribosomal S6 kinase-4 (RSK4) that is still largely uncharacterized. In this study we identified a new RSK4 transcription initiation site and several alternative splice sites with a 5’RACE approach. The resulting mRNA variants encompass four possible first start codons. The first 15 nucleotides (nt) of exon 22 in mouse and the penultimate exon in both human (exon 21) and mouse (exon 24) RSK4 underwent alternative splicing, although the penultimate exon deleted variant appeared mainly in cell clines, but not in most normal tissues. Demethylation agent 5-azacytidine inhibited the deletion of the penultimate exon whereas two indolocarbazole-derived inhibitors of cyclin dependent kinase 4 or 6 induced deletion of the first 39 nt from exon 21 of human RSK4. In all human cancer cell lines studied, the 90-kD wild type RSK4 was sparse but, surprisingly, several isoforms at or smaller than 72-kD were expressed as detected by seven different antibodies. On immunoblots, each of these smaller isoforms often appeared as a duplet or triplet and the levels of these isoforms varied greatly among different cell lines and culture conditions. Cyclin D1 inhibited RSK4 expression and serum starvation enhanced the inhibition, whereas c-Myc and RSK4 inhibited cyclin D1. The effects of RSK4 on cell growth, cell death and chemoresponse depended on the mRNA variant or the protein isoform expressed, on the specificity of the cell lines, as well as on the anchorage-dependent or -independent growth conditions and the in vivo situation. Moreover, we also observed that even a given cDNA might be expressed to multiple proteins; therefore, when using a cDNA, one needs to exclude this possibility before attribution of the biological results from the cDNA to the anticipated protein. Collectively, our results suggest that whether RSK4 is oncogenic or tumor suppressive depends on many factors.
PMCID: PMC3427418  PMID: 22614021
24.  Evaluation of Fluorine-labeled Gastrin-Releasing Peptide Receptor (GRPR) Agonists and Antagonists by LC/MS 
Amino acids  2012;43(4):1625-1632.
An LC/MS method was used to evaluate 2-fluoropropionyl (FP) and 4-fluorobenzoyl (FB) modified bombsin peptides: GRPR agonist [Aca-QWAVGHLM-NH2] and antagonist [fQWAVGHL-NHEt], and their hydrophilic linker modified counterparts with the attachment of GGGRDN sequence. This study developed strategies to evaluate the in vitro receptor mediated cell uptake and metabolic profile of the various GRPR agonists and antagonists. We identified the metabolites produced by rat hepatocytes, and quantitatively analyzed the uptake and internalization of the ligands in PC-3 human prostate cancer cells. The major metabolites of both GRPR agonists and antagonists were the result of peptide bond hydrolysis between WA and AV. The agonists also formed a unique metabolite resulting from hydrolysis of the C-terminal amide. The antagonists showed significantly higher stability against metabolism compared to the agonists in rat hepatocytes. The directly modified agonists (FP-BBN and FB-BBN) had higher internalization with similar cell binding compared to the unmodified agonist (BBN), whereas the hydrophilic linker modified agonists (G-BBN and FG-BBN) had much lower total cell uptake. The labeled antagonist (FP-NBBN, FB-NBBN, G-NBBN and FP-G-NBBN) displayed lower internalization. The optimal imaging agent will depend on the interplay of ligand metabolism, cellular uptake, and internalization in vivo.
PMCID: PMC3387330  PMID: 22354143
LC/MS; Gastrin releasing peptide receptor (GRPR); Bombesin (BBN); Agonist; antagonist; PET
25.  MRAS Genetic Variation Is Associated with Atherothrombotic Stroke in the Han Chinese Population 
Background and Purpose
Atherothrombotic cerebral infarction [atherothrombotic stroke (ATS)] shares common risk factors and pathophysiological mechanisms with coronary artery disease (CAD), and both diseases appear to have common susceptibility loci. The muscle RAS oncogene homolog gene (MRAS) has been identified as a susceptibility locus for CAD and is implicated in atherosclerosis. The aim of this study was to elucidate whether the single-nucleotide polymorphisms (SNPs) and haplotypes of MRAS are associated with increased risk of ATS in a population of Han Chinese.
A case-controlled association study was conducted in which only patients with ATS (identified as a major subtype in the Korean modification of the Trial of Org 10172 in Acute Stroke Treatment classification) were enrolled. Subgroup analyses were carried out to determine whether the effect of the MRAS polymorphism was specific to age and gender among the subjects.
In total, 194 ATS and 186 control subjects were included in the present study. Two tagging SNPs were identified in MRAS (rs40593 and rs3755751). A multivariate regression analysis revealed a positive association between rs40593 and ATS under dominant and additive models after adjustment for covariates. Subgroup analyses revealed that there were no gender differences with respect to allele or genotype frequencies between the groups. The AG genotype for rs40593 (p=0.028), the CT genotype for rs3755751 (p=0.036), and G-allele carriers (AG plus GG) for rs40593 (p=0.015) exhibited a significant protective effect among those aged ≥45 years. For the haplotype analysis, ATS subjects aged ≥45 years had a higher frequency of the ACAC haplotype (76.0%) than the controls (68.1%; p<0.05); that haplotype was associated with an increased risk of ATS.
The obtained data suggest a positive association between MRAS and ATS among the Han Chinese. Further studies should be performed with larger sample and among different ethnic populations, and gene-gene or gene-environment interactions should be considered.
PMCID: PMC3840132  PMID: 24285963
ischemic stroke; atherothrombotic stroke; single-nucleotide polymorphism; haplotype; genetic variation

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