A two-stage genome-wide association study identifies novel germline genetic variations in CACNA2D3 associated with radiotherapy response in nasopharyngeal carcinoma.

BACKGROUND: Radiotherapy (RT) is the standard treatment for nasopharyngeal carcinoma (NPC). However, due to individual differences in radiosensitivity, biomarkers are needed to tailored radiotherapy to cancer patients. However, comprehensive genome-wide radiogenomic studies on them are still lacking. The aim of this study was to identify genetic variants associated with radiotherapy response in patients with NPC. METHODS: This was a large­scale genome-wide association analysis (GWAS) including a total of 981 patients. 319 individuals in the discovery stage were genotyped for 688,783 SNPs using whole genome-wide screening microarray. Significant loci were further genotyped using MassARRAY system and TaqMan SNP assays in the validation stages of 847 patients. This study used logistic regression analysis and multiple bioinformatics tools such as PLINK, LocusZoom, LDBlockShow, GTEx, Pancan-meQTL and FUMA to examine genetic variants associated with radiotherapy efficacy in NPC. RESULTS: After genome-wide level analysis, 19 SNPs entered the validation stage (P < 1 × 10- 6), and rs11130424 ultimately showed statistical significance among these SNPs. The efficacy was better in minor allele carriers of rs11130424 than in major allele carriers. Further stratified analysis showed that the association existed in patients in the EBV-positive, smoking, and late-stage (III and IV) subgroups and in patients who underwent both concurrent chemoradiotherapy and induction/adjuvant chemotherapy. CONCLUSION: Our study showed that rs11130424 in the CACNA2D3 gene was associated with sensitivity to radiotherapy in NPC patients. TRIAL REGISTRATION NUMBER: Effect of genetic polymorphism on nasopharyngeal carcinoma chemoradiotherapy reaction, ChiCTR-OPC-14005257, Registered 18 September 2014, http://www.chictr.org.cn/showproj.aspx?proj=9546 .

A two-stage genome-wide association study to identify novel genetic loci associated with acute radiotherapy toxicity in nasopharyngeal carcinoma.

BACKGROUND: Genetic variants associated with acute side effects of radiotherapy in nasopharyngeal carcinoma (NPC) remain largely unknown. METHODS: We performed a two-stage genome-wide association analysis including a total of 1084 patients, where 319 individuals in the discovery stage were genotyped for 688,783 SNPs using whole genome-wide screening microarray. Significant variants were then validated in an independent cohort of 765 patients using the MassARRAY system. Gene mapping, linkage disequilibrium, genome-wide association analysis, and polygenic risk score were conducted or calculated using FUMA, LDBlockShow, PLINK, and PRSice software programs, respectively. RESULTS: Five SNPs (rs6711678, rs4848597, rs4848598, rs2091255, and rs584547) showed statistical significance after validation. Radiotherapy toxicity was more serious in mutant minor allele carriers of all five SNPs. Stratified analysis further indicated that rs6711678, rs4848597, rs4848598, and rs2091255 correlated with skin toxicity in patients of EBV positive, late stage (III and IV), receiving both concurrent chemoradiotherapy and induction/adjuvant chemotherapy, and with OR values ranging from 1.92 to 2.66. For rs584547, high occurrence of dysphagia was found in A allele carriers in both the discovery (P = 1.27 × 10- 6, OR = 1.55) and validation (P = 0.002, OR = 4.20) cohorts. Furthermore, prediction models integrating both genetic and clinical factors for skin reaction and dysphagia were established. The area under curve (AUC) value of receiver operating characteristic (ROC) curves were 0.657 (skin reaction) and 0.788 (dysphagia). CONCLUSIONS: Rs6711678, rs4848597, rs4848598, and rs2091255 on chromosome 2q14.2 and rs584547 were found to be novel risk loci for skin toxicity and dysphagia in NPC patients receiving radiotherapy. TRIAL REGISTRATION: Chinese Clinical Trial Register (registration number: ChiCTR-OPC-14005257 and CTXY-140007-2).

A retroperitoneal bronchogenic cyst clinically mimicking an adrenal mass: three case reports and a literature review.

Bronchogenic cysts are a congenital primitive foregut-derived developmental malformation, generally occurring in the posterior mediastinum. Their development in the retroperitoneum is extremely rare. Imaging techniques, such as multidetector computed tomography (MDCT), are typically effective in the detection of these lesions. Here, we describe three cases of a retroperitoneal cyst presenting as a para-adrenal mass. Only one boy presented with abdominal pain, and the other two showed no clinical symptoms. Endocrinological evaluation of all three cases was performed, and no adrenal hormone secretion was detected. All three cases were misdiagnosed preoperatively. Each patient underwent surgery, and one symptomatic patient became asymptomatic after surgery. Pathologic examination confirmed all three masses as bronchogenic cysts. The three cases showed some similar MDCT imaging features, including a complete adrenal structure, a cystic or solid mass in the adrenal region, and no obvious enhancement. Therefore, bronchogenic cysts should be considered in the differential diagnosis of retroperitoneal masses, even though accurate preoperative diagnosis remains difficult. A contrast-enhanced MDCT scan may be useful for differentiating hyper-attenuated cysts from other soft tissue masses.

A Ratiometric and Colorimetric Hemicyanine Fluorescent Probe for Detection of SO2 Derivatives and Its Applications in Bioimaging.

Based upon the intramolecular charge transfer (ICT) mechanism, a novel ratiometric fluorescent probe EB was developed to detect SO32-/HSO3-. The probe displayed both colorimetric and ratiometric responses toward SO32-/HSO3-. It displayed a quick response (within 60 s), good selectivity and high sensitivity (a detection limit of 28 nM) towards SO32-/HSO3-. The SO32-/HSO3- sensing mechanism was confirmed as the Michael addition reaction by ESI-MS. Moreover, the probe could be applied to measure the level of sulfite in real samples, like sugar and chrysanthemum, and it could also be used to detect SO32-/HSO3- in HepG2 cells through confocal fluorescence microscopy, which proved its practical application in clinical diagnosis.

Left Ventricular Involvement in Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy Predicts Adverse Clinical Outcomes: A Cardiovascular Magnetic Resonance Feature Tracking Study.

The aim of this study was to investigate left ventricular (LV) global myocardial strain and LV involvement characteristics in patients with arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) and to evaluate their predictive value of adverse cardiac events. Sixty consecutive ARVD/C patients with a definite diagnosis of ARVD/C who underwent CMR examination and thirty-four healthy controls were enrolled retrospectively. The CMR images were analyzed for LV myocardial strain and the presence of LV involvement. The endpoint was defined as a composite of sustained ventricular tachycardia or fibrillation, cardiac death, resuscitated cardiac arrest, heart transplantation, and appropriate implantable cardioverter-defibrillator shock. LV global longitudinal (GLS), circumferential (GCS), and radial strain (GRS) were significantly impaired in ARVC/D patients compared to healthy controls (GLS: -13.89 ± 3.26% vs. -16.68 ± 2.74%, GCS: -15.65 ± 3.40% vs. -19.20 ± 2.23%, GRS: 34.57 ± 11.98% vs. 49.92 ± 12.59%; P < 0.001 for all). Even in ARVC/D patients with preserved LVEF, LV GLS, GCS and GRS were also significantly reduced than in controls. During a mean follow-up period of 4.10 ± 1.77 years, the endpoint was reached in 17 patients. LV GLS >-12.65% (HR, 3.58; 95%CI, 1.14 to 11.25; p = 0.029) and history of syncope (HR, 4.99; 95%CI, 1.88 to 13.24; p = 0.001) were the only independent predictors of cardiac outcomes. The LV myocardial deformation derived from FT CMR was significantly impaired in ARVD/C patients, and this alteration can occur before the impairment of LVEF. LV GLS >-12.65% and history of syncope were the only independent prognostic markers of adverse cardiac outcomes.

Specific inhibitor of Notch­3 enhances the sensitivity of NSCLC cells to gemcitabine.

Notch­3 is a receptor of the Notch signaling pathway and plays an important role in regulating self­renewal, differentiation and apoptosis in cancer cells. Overexpression of Notch­3 has been proved to be associated with resistance to gemcitabine (GEM) and poor patient prognosis for various malignant tumors. In the present study, two non­small cell lung cancer (NSCLC) cell lines, H1299 and A549, were induced with GEM for two months and then were treated with various concentrations of a Notch signaling blocker, N­[N­(3,5­difluorophenacetyl)­L­alanyl]­S­phenylglycine t­butyl ester (DAPT), with the goal of reducing expression of Notch intracellular domain 3 (NICD3). Both cell lines were subsequently treated with either DAPT or DAPT combined with GEM and then viability, apoptosis, colony formation and cell count assays were performed. DAPT treatment effectively downregulated the expression of NICD3 in both cell lines. DAPT combined with GEM also significantly reduced the percentage of viable cells in both cell lines, while increasing the percentage of apoptotic cells, compared with GEM alone. In the clonogenicity assays, the combination of DAPT and GEM led to a decrease in clone numbers and significantly greater inhibition of the H1299 and A549 cells compared to treatment with DAPT or GEM alone. Meanwhile, levels of the apoptosis­related proteins, Bcl­2 and Bax, were found to be affected by the various treatments. Thus Notch­3 appears to be a promising target for gene therapy and DAPT is able to mediate a strong antitumor effect in NSCLC cells that overexpress Notch­3. Further studies of a combined treatment regimen with DAPT and GEM are warranted and may provide greater efficacy and safety in the treatment of NSCLC patients.

Assessment of tetralogy of Fallot-associated congenital extracardiac vascular anomalies in pediatric patients using low-dose dual-source computed tomography.

BACKGROUND: To investigate the diagnostic value of dual-source computed tomography (DSCT) in the evaluation of tetralogy of Fallot (TOF)-associated extracardiac vascular abnormalities in pediatric patients compared with transthoracic echocardiography (TTE). METHODS: One hundred and twenty-three pediatric patients diagnosed with TOF were included in this retrospective study. All patients underwent DSCT and TTE preoperatively. All associated extracardiac vascular abnormalities and their percentages were recorded. The diagnostic performances of DSCT and TTE were compared based on the surgical results. The image quality of DSCT was rated, and the effective radiation dose (ED) was calculated. RESULTS: A total of 159 associated extracardiac vascular deformities were confirmed by surgery. Patent ductus arteriosus (36, 22.64%), right-sided aortic arch (29, 18.24%), and pulmonary valve stenosis (23, 14.47%) were the most common associated extracardiac vascular abnormalities. DSCT was superior to TTE in demonstrating associated extracardiac anomalies (diagnostic accuracy: 99.13% vs. 97.39%; sensitivity: 92.45% vs. 77.07%; specificity: 99.81% vs. 99.42%). The agreement on grading the image quality of DSCT was excellent (κ = 0.80), and the mean score of the image quality was 3.39 ± 0.50. The mean ED of DSCT was 0.86 ± 0.47 mSv. CONCLUSIONS: Compared to TTE, low-dose DSCT has high diagnostic accuracy in the depiction of associated extracardiac vascular anomalies in pediatric patients with TOF, and could provide more morphological details for surgeons.

[Hypoxia regulates the expression of OPG/RANKL mRNA in rat bone marrow mesenchymal stem cells].

PURPOSE: To investigate the effects of hypoxia on the expression of osteoprotegerin (OPG) and receptor activator of nuclear factor kappa B ligand (RANKL) mRNA in rat bone marrow mesenchymal stem cells (rBMSCs). METHODS: rBMSCs were isolated and cultured by whole bone marrow cell adherent method, and an optimal hypoxic preconditioning model was established with CoCl2 (cobalt chloride). rBMSCs were incubated in cell culture mediums with different concentrations of CoCl2 (final concentrations of CoCl2 were 0, 50, 100, 200, 400 µmol/L) and incubated for different times. MTT assay was applied to detect the effect of CoCl2 on cell proliferation. mRNA and protein expression of HIF-1α of rBMSCs was detected by real-time PCR and Western blot. After treated with 100 µmol/L CoCl2 for 0, 12, 24, 48, 72, 96 h, the expression of rBMSCs OPG/RANKL mRNA were detected by real-time PCR. The differences in distribution of each genotype were analyzed with SPSS 18.0 software package. RESULTS: Compared with the control group, 200, 400 µmol/L CoCl2 inhibited the proliferation of rBMSCs (P<0.05). However, 50, 100 µmol/L CoCl2 had no significant impact on the proliferation of rBMSCs (P>0.05). Real-time PCR and Western blot showed that HIF-1α expression in 50 µmol/L and 100 µmol/L CoCl2 groups was significantly higher than the control group; the effect of 100 µmol/L CoCl2 was significantly greater than 50 µmol/L CoCl2. After cultivated in hypoxia condition for 12 h, the expression of OPG and RANKL mRNA in rBMSCs didn't change significantly (P>0.05). After cultured hypoxia condition for 24, 48, 72, 96 h, the expression of OPG mRNA in rBMSCs increased while the RANKL decreased, thus the ratio of OPG/RANKL increased and the difference was significant (P<0.05). CONCLUSIONS: Hypoxia can regulate the mRNA expression of OPG and RANKL mRNA in rBMSCs and significantly promote osteogenic differentiation.

Reversal effect and mechanism of Ginkgo biloba exocarp extracts in multidrug resistance of mice S180 tumor cells.

The aim of the present study was to investigate the reversal effect and its related mechanism of Ginkgo biloba exocarp extracts (GBEEs) in obtained multidrug resistance (MDR) of mice S180 tumor cells in vitro and in vivo. In order to simulate the clinical PFC [cis-dichlorodiamineplatinum, cisplatin (DDP) + fluorouracil (FU), FU+cyclophosphamide and cyclophosphamide] scheme, a gradually increasing dose was administered in a phased induction in order to induce S180 cells in vivo and to make them obtain multidrug resistance. The results in vitro demonstrated that GBEE could significantly increase the IC50 of DDP on S180 MDR cells, increase the accumulation of Adriamycin (ADR) and rhodamine 123 (Rho 123), and reduce the efflux of Rho 123 of S180 MDR cells. The results from the in vivo treatment with a combination of GBEE and DDP to S180 MDR ascites tumor in mice demonstrated that each dose of GBEE could effectively reverse the drug-resistance of S180 MDR cells to DDP in order to extend the survival time of mice with ascite tumors and inhibit tumor growth in solid tumor mice. In addition, GBEE effectively inhibited the expression of MDR-1 mRNA and multidrug resistance-associated protein-1 mRNA in S180 MDR cells of ascites tumor in mice and improved the expression levels of cytokines, including interleukin (IL)-3, IL-18 and interferon-γ in the blood serum of S180 MDR tumor-bearing mice. The present study showed that the mechanism of GBEE reversal of MDR may be associated with the inhibition of the functional activity of P-glycoprotein, the downregulation of drug resistance related gene expression of S180 MDR cells and the improvement of the production of related serum cytokines of S180 MDR tumor mice.

[MRI diagnosis of osteochondral lesions in the talus and the dynamic follow up analysis after osteochondral transplantation].

OBJECTIVE: To investigate MRI findings of osteochondral lesions in the talus;to evaluate the value of MRI in diagnosing and determining the stage of osteochondral lesions;to analyze the follow up clinical value of MRI in osteochondral transplantation of autologous bone. METHODS: A total of 79 patients from February 2013 to March 2015 had been retrospectively analyzed. All the patients were treated in our hospital. The ankle arthroscopy results were used as the reference standard, and the accuracy of MRI in diagnosis and Hepple staging had been investigated. Fifteen patients with cartilage transplantation of autologous bone were followed up with MRI examination and evaluation of cartilage repair score(MOCART) after one year. The values of MRI in the postoperative follow up were analyzed. RESULTS: Hepple staging of 79 patients was shown as follows:7 cases of stage I, 12 cases of stage II, 24 cases of stage III, 16 cases of stage IV, and 20 cases of stage V. Ankle arthroscopy grading of 59 patients in this group(in addition of 20 cases of stage V):2 cases of grade A, 2 cases of grade B, 4 cases of grade C, 14 cases of grade D, 22 cases of grade E, and 15 cases of grade F. The accuracy rate of MRI in determining Hepple V was set at 100%, and Hepple stage I corresponds to the arthroscopic A, B, C stage, stage II corresponds to D stage, stage III corresponds to E stage, stage IV corresponds to F stage. The accuracy rate of MRI in determining Hepple stage I to IV was 87.5%, 85.7%, 95.4% and 93.3% respectively. After cartilage transplantation of autologous bone, MRI of 15 patients showed cartilage surface in transplanted area was smooth, bone healed well, and the surrounding edema disappeared. The MOCART was 30 to 80 scores with an average score 59.0±15.6;9 cases of these 15 patients were(9/15, 60%) higher than 60 score. CONCLUSIONS: MRI plays a significant role in clinical diagnosis and staging of the talus osteochondral injury. As a method of long term follow up after cartilage transplantation, MRI can well evaluate the rapair of the postoperative osteochondral injury.

Improved method for synthesis of cysteine modified hyaluronic acid for in situ hydrogel formation.

We developed a new strategy for the functionalization of hyaluronic acid by chemical modification of its C-6 hydroxyl groups through an ether bond to obtain a cysteine-hyaluronic acid conjugate. This conjugate is suitable to prepare injectable and in situ formed hydrogels cross-linked by native chemical ligation and Michael addition under mild conditions.

Iron Carbide Nanoparticles Encapsulated in Mesoporous Fe-N-Doped Carbon Nanofibers for Efficient Electrocatalysis.

Exploring low-cost and high-performance nonprecious metal catalysts (NPMCs) for oxygen reduction reaction (ORR) in fuel cells and metal-air batteries is crucial for the commercialization of these energy conversion and storage devices. Here we report a novel NPMC consisting of Fe3 C nanoparticles encapsulated in mesoporous Fe-N-doped carbon nanofibers, which is synthesized by a cost-effective method using carbonaceous nanofibers, pyrrole, and FeCl3 as precursors. The electrocatalyst exhibits outstanding ORR activity (onset potential of -0.02 V and half-wave potential of -0.140 V) closely comparable to the state-of-the-art Pt/C catalyst in alkaline media, and good ORR activity in acidic media, which is among the highest reported activities of NPMCs.

[The role of arecoline on hepatic insulin resistance in type 2 diabetes rats].

OBJECTIVE: To explore the effects of arecoline on hepatic insulin resistance in type 2 diabetes rats and to elucidate its possible mechanism. METHODS: Forty five Wistar rats were fed with high fructose diet for 12 weeks to induce type 2 diabetic rat model. rats were randomly divided into 5 groups (n = 8): control group, model group and model group were treated with different dose (0, 0.5, 1, 5 mg/kg) of arecoline. After 4 weeks, the fasting blood glucose, blood lipid and insulin level measured , mRNA expression of liver constitutive androstane receptor (CAR), pregnane X receptor (PXR), glucose-6-phosphatase (G6Pase), phosphoenolpyruvate carboxykinase (PEPCK), interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) were detected by reverse transcription polymerase chain reaction (RT-PCR), the protein expression of p-AKT and glucose transporter4 (GLUT4) were detected by Western blot. RESULTS: 1.5 mg/kg arecoline could significantly decrease the level of fasting blood glucose, blood lipid, blood insulin level and liver G6Pase, PEPCK, IL-6, TNF-alpha mRNA level in type 2 diabetes rats. 1.5 mg/kg arecoline also could significantly increase CAR, PXR mRNA level and p-AKT and GLUT4 protein expression. CONCLUSION: Arecoline improved hepatic insulin resistance in type 2 diabetes rats by increasing the mRNA levels of CAR and PXR leading to the creased glucose metabolism and inflammation related genes expression.

Induction of rapid cell death by an environmental isolate of Legionella pneumophila in mouse macrophages.

Legionella pneumophila, the etiological agent for Legionnaires' disease, is ubiquitous in the aqueous environment, where it replicates as an intracellular parasite of free-living protozoa. Our understanding of L. pneumophila pathogenicity is obtained mostly from study of derivatives of several clinical isolates, which employ almost identical virulent determinants to exploit host functions. To determine whether environmental L. pneumophila isolates interact similarly with the model host systems, we analyzed intracellular replication of several recently isolated such strains and found that these strains cannot productively grow in bone marrow-derived macrophages of A/J mice, which are permissive for all examined laboratory strains. By focusing on one strain called LPE509, we found that its deficiency in intracellular replication in primary A/J macrophages is not caused by the lack of important pathogenic determinants because this strain replicates proficiently in two protozoan hosts and the human macrophage U937 cell. We also found that in the early phase of infection, the trafficking of this strain in A/J macrophages is similar to that of JR32, a derivative of strain Philadelphia 1. Furthermore, infection of these cells by LPE509 caused extensive cell death in a process that requires the Dot/Icm type IV secretion system. Finally, we showed that the cell death is caused neither by the activation of the NAIP5/NLRC4 inflammasome nor by the recently described caspase 11-dependent pathway. Our results revealed that some environmental L. pneumophila strains are unable to overcome the defense conferred by primary macrophages from mice known to be permissive for laboratory L. pneumophila strains. These results also suggest the existence of a host immune surveillance mechanism differing from those currently known in responding to L. pneumophila infection.

A novel mechanism of formaldehyde neurotoxicity: inhibition of hydrogen sulfide generation by promoting overproduction of nitric oxide.

BACKGROUND: Formaldehyde (FA) induces neurotoxicity by overproduction of intracellular reactive oxygen species (ROS). Increasing studies have shown that hydrogen sulfide (H(2)S), an endogenous gastransmitter, protects nerve cells against oxidative stress by its antioxidant effect. It has been shown that overproduction of nitric oxide (NO) inhibits the activity of cystathionine-beta-synthase (CBS), the predominant H(2)S-generating enzyme in the central nervous system. OBJECTIVE: We hypothesize that FA-caused neurotoxicity involves the deficiency of this endogenous protective antioxidant gas, which results from excessive generation of NO. The aim of this study is to evaluate whether FA disturbs H(2)S synthesis in PC12 cells, and whether this disturbance is associated with overproduction of NO. PRINCIPAL FINDINGS: We showed that exposure of PC12 cells to FA causes reduction of viability, inhibition of CBS expression, decrease of endogenous H(2)S production, and NO production. CBS silencing deteriorates FA-induced decreases in endogenous H(2)S generation, neurotoxicity, and intracellular ROS accumulation in PC12 cells; while ADMA, a specific inhibitor of NOS significantly attenuates FA-induced decreases in endogenous H(2)S generation, neurotoxicity, and intracellular ROS accumulation in PC12 cells. CONCLUSION/SIGNIFICANCE: Our data indicate that FA induces neurotoxicity by inhibiting the generation of H(2)S through excess of NO and suggest that strategies to manipulate endogenous H(2)S could open a suitable novel therapeutic avenue for FA-induced neurotoxicity.

[Analysis of clinical characteristics and risk factors associated with prognosis of patients with candidemia].

OBJECTIVE: To explore the microbiological and clinical characteristics of patients with candidemia and analyze their prognostic risk factors. METHODS: A retrospective analysis was conducted for hospitalized patients with candidemia from January 2008 to December 2012 at Affiliated Zhongshan Hospital, Fudan University. Pathogen spectrum, resistance pattern, underlying diseases, therapy received and patient prognosis were collected by chart review. The univariate and multivariate Logistic regression analyses were used to determine the prognostic risk factors of candidemia. RESULTS: A total of 138 inpatients were identified. There were 98 males and 40 females with a mean age of (61.3 ± 16.6) years. The morbidity rate of candidemia in annual discharged patients was 0.034%-0.051%. The most common pathogens were Candida albicans (n = 72, 52.2%), Candida parapsilosis (n = 29, 21.0%) and Candida tropicalis (n = 16, 11.6%). The antibiotic susceptible rate of azole for Candida was 90.9%-97.4% while 55.6%-83.3% for Candida tropicalis. The overall case fatality rate of candidemia was 39.1% (54/138) while the attributable case fatality rate 31.9% (44/138). Multivariate Logistic regression analysis indicated acute physiology and chronic health evaluation II(APACHE II) score ≥ 20 points (OR = 8.025, 95%CI: 2.032-31.696, P = 0.003), hypoproteinemia (OR = 6.213, 95%CI: 1.849-20.879, P = 0.003), concurrent bacteremia (OR = 5.541, 95%CI: 1.576-19.487, P = 0.008) and indwelling urethral catheter (OR = 13.776, 95%CI: 1.402-135.352, P = 0.024) were the independent risk factors of candidemia-related mortality, while removal or replacement of central venous catheter (OR = 0.231, 59%CI: 0.075-0.716, P = 0.011) and surgery within 30 days (OR = 0.206, 95%CI: 0.050-0.857, P = 0.030) were the protective factors. CONCLUSIONS: Candida albicans is the most common causative agent. The case fatality rate of candidemia has remained high. APACHE II score ≥ 20 points, hypoproteinemia, indwelling urethral catheter and concurrent bacteremia are independent risk factors attributing to candidemia-related mortality while removal or replacement of central venous catheter and surgery within 30 days are the protective ones.

Arecoline improves vascular endothelial function in high fructose-fed rats via increasing cystathionine-γ-lyase expression and activating K(ATP) channels.

AIM: To investigate the effect of arecoline, a major component of betel nut, on vascular endothelial function in high fructose-fed rats and the potential mechanisms underlying the effect. METHODS: Male Wistar rats were fed a high-fructose or control diet for 16 weeks. At the beginning of week 13, the rats were injected ip with low (0.5 mg·kg(-1)·d(-1)), medium (1.0 mg·kg(-1)·d(-1)) or high (5.0 mg·kg(-1)·d(-1)) doses of arecoline for 4 weeks. At the termination of the treatments, blood was collected, fasting blood glucose (FBG) and serum insulin (FSI) levels were measured, and insulin sensitivity index (ISI) was calculated. The thoracic aortas were isolated and aortic rings were prepared for studying ACh-induced endothelium-dependent vasorelaxation (EDVR). The mRNA and protein expression of cystathionine-γ-lyase (CSE) in the thoracic aortas was analyzed using RT-PCR and Western blot analysis, respectively. RESULTS: In high fructose-fed rats, the levels of FBG and FSI were remarkably increased, whereas the ISI and the mRNA and protein expression of CSE were significantly decreased. ACh-induced EDVR in the aortic rings from high fructose-fed rats was remarkably reduced. These changes were reversed by treatment with high dose arecoline. Pretreatment of the aortic rings rings from high fructose-fed rats with the CSE inhibitor propargylglycine (10 mmol/L) or the ATP-sensitive potassium (K(ATP)) channel blocker glibenclamide (10 mmol/L) abolished the restoration of ACh-induced EDVR by high dose arecoline. On the contrary, treatment with high dose arecoline significantly impaired ACh-induced EDVR in the aortic rings from control rats, and pretreatment with propargylglycine or glibenclamide did not cause further changes. CONCLUSION: Arecoline treatment improves ACh-induced EDVR in high fructose-fed rats, and the potential mechanism of action might be associated with increase of CSE expression and activation of K(ATP) channels by arecoline.

Involvement of K(ATP)/PI (3)K/AKT/Bcl-2 pathway in hydrogen sulfide-induced neuroprotection against the toxicity of 1-methy-4-phenylpyridinium ion.

We previously reported that hydrogen sulfide (H(2)S) produces protection in PC12 cells during 1-methy-4-phenylpyridinium ion (MPP(+)) challenge. The present study aims to clarify the mechanisms underlying the neuroprotective effects of H(2)S. We showed that both glybenclamide, an ATP-sensitive potassium (K(ATP)) channel blocker, and LY294002, a specific PI(3)K-AKT pathway inhibitor, reversed the neuroprotective effect of NaHS (a H(2)S donor) against MPP(+)-induced cytotoxicity to PC12 cells and that NaHS up-regulated the activity of AKT in PC12 cells, which was abolished by blockade of K(ATP) channels with glybenclamide. In addition, NaHS up-regulated the expression of Bcl-2 and blocked MPP(+)-induced down-regulation of Bcl-2, and this augmentation of Bcl-2 expression was prevented by both glybenclamide and LY294002. These data provided the evidence that the neuroprotective action of H(2)S against MPP(+) toxicity to PC12 cells is via the K(ATP)/PI(3)K/AKT/Bcl-2 pathway. We also demonstrated that NaHS attenuated the inhibitory effect of MPP(+) ERK1/2 activation in PC12 cells, whereas U0126, a specific MEK inhibitor, did not reverse the neuroprotective effect of NaHS, which indicated that attenuating MPP(+)-triggered down-regulation of ERK1/2 activation is involved in the protection of H(2)S against MPP(+) neurotoxicity, but ERK1/2 is not an essential effector mediating the neuroprotective effect of H(2)S. In conclusion, the present observations identify a crucial role of the K(ATP)/PI(3)K/AKT/Bcl-2 pathway in H(2)S-exerted neuroprotection against the toxicity of MPP(+). Findings from the present study will help shed light on the mechanisms of H(2)S-elicited neuroprotective effects on MPP(+) toxicity.

Endogenous hydrogen sulfide is involved in asymmetric dimethylarginine-induced protection against neurotoxicity of 1-methyl-4-phenyl-pyridinium ion.

Asymmetric dimethylarginine (ADMA), an endogenous nitric oxide synthase (NOS) inhibitor, is profoundly protective against 1-methy-4-phenylpyridinium ion (MPP+)-induced neurotoxicity. Reactive oxygen species (ROS) overproduction contributes to the neurotoxicity of MPP+; while hydrogen sulfide (H2S) is a pivotal endogenous antioxidant. This study is to assess the potential role of endogenous H2S in the neuroprotection of ADMA against MPP+-induced toxicity in PC12 cells. We showed that ADMA prevented MPP+-induced inhibition of endogenous H2S generation through inhibiting the down-regulation of cystathionine-ß-synthetase (CBS, the major enzyme responsible for endogenous H2S generation in PC12 cells) expression and activity elicited by MPP+. ADMA obviously attenuated MPP+-triggered accumulation of intracellular ROS, dissipation of mitochondrial membrane potential (MMP), release of cytochrome c (Cyt-c), and downregulation of Bcl-2 protein expression in PC12 cells. Inhibition of CBS activity by amino-oxyacetate and CBS silencing with a short hairpin RNA vector targeting rat CBS gene reversed the protective action of ADMA against MPP+-caused cytotoxicity, ROS overproduction, and MMP loss in PC12 cells. These results indicate that the protection of ADMA against MPP+-mediated neurotoxicity involves the melioration of MPP+-induced inhibition of endogenous H2S generation. Our findings suggest that modulation of H2S production provide new therapeutic targets for the treatment of neurodegenerative disease, such as Parkinson's disease.

Formaldehyde induces neurotoxicity to PC12 cells involving inhibition of paraoxonase-1 expression and activity.

1. Formaldehyde (FA) has been found to cause toxicity to neurons. However, its neurotoxic mechanisms have not yet been clarified. Increasing evidence has shown that oxidative damage is one of the most critical effects of formaldehyde exposure. Paraoxonase-1 (PON-1) is a pivotal endogenous anti-oxidant. Thus, we hypothesized that FA-mediated downregulation of PON1 is associated with its neurotoxicity. 2. In the present work, we used PC12 cells to study the neurotoxicity of FA and explore whether PON-1 is implicated in FA-induced neurotoxicity. 3. We found that FA has potent cytotoxic and apoptotic effects on PC12 cells. FA induces an accumulation of intracellular reactive oxygen species along with downregulation of Bcl-2 expression, as well as increased cytochrome c release. FA significantly suppressed the expression and activity of PON-1 in PC12 cells. Furthermore, H(2)S, an endogenous anti-oxidant gas, antagonizes FA-induced cytotoxicity as well as 2-hydroxyquinoline, a specific inhibitor of PON-1, which also induces cytotoxicity to PC12 cells. 4. The results of the present study provide, for the first time, evidence that the inhibitory effect on PON-1 expression and activity is involved in the neurotoxicity of FA, and suggest a promising role of PON-1 as a novel therapeutic strategy for FA-mediated toxicity.