Hexavalent chromium [Cr(IV)], a well-known industrial waste product and an environmental pollutant, is recognized as a human carcinogen. But its mechanisms of carcinogenicity remain unclear, and recent studies suggest that DNA methylation may play an important role in the carcinogenesis of Cr(IV). The aim of our study was to investigate the effects of Cr(IV) on cell cycle progress, global DNA methylation, and DNA methylation of p16 gene. A human B lymphoblastoid cell line and a human lung cell line A549 were exposed to 5–15 µM potassium dichromate or 1.25–5 µg/cm2 lead chromate for 2–24 hours. Cell cycle was arrested at G1 phase by both compounds in 24 hours exposure group, but global hypomethylation occurred earlier than cell cycle arrest, and the hypomethylation status maintained for more than 20 hours. The mRNA expression of p16 was significantly up-regulated by Cr(IV), especially by potassium dichromate, and the mRNA expression of cyclin-dependent kinases (CDK4 and CDK6) was significantly down-regulated. But protein expression analysis showed very little change of p16 gene. Both qualitative and quantitative results showed that DNA methylation status of p16 remained unchanged. Collectively, our data suggested that global hypomethylation was possibly responsible for Cr(IV) - induced G1 phase arrest,but DNA methylation might not be related to up-regulation of p16 gene by Cr(IV).
AIM: To assess the technical safety and efficacy of transcatheter arterial chemoembolization (TACE) combined with immediate radiofrequency ablation (RFA) for large hepatocellular carcinomas (HCC) (maximum diameter ≥ 5 cm).
METHODS: Individual lesions in 18 patients with HCCs (mean maximum diameter: 7.5 cm; range: 5.1-15.5 cm) were treated by TACE combined with percutaneous RFA between January 2010 and June 2012. All of the patients had previously undergone one to four cycles of TACE treatment. Regular imaging and laboratory tests were performed to evaluate the rate of technical success, technique-related complications, local-regional tumor responses, recurrence-free survival time and survival rate after treatment.
RESULTS: Technical success was achieved for all 18 visible HCCs. Complete response (CR) was observed in 17 cases, and partial response was observed in 1 case 1 mo after intervention. The CR rate was 94.4%. Local tumors were mainly characterized by coagulative necrosis. During follow-up (2-29 mo), the mean recurrence-free survival time was 16.8 ± 4.0 mo in 17 cases of CR. The estimated overall survival rate at 6, 12, and 18 mo was 100%. No major complications were observed. Levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in the blood of 17 patients transiently increased on the third day after treatment (ALT 200.4 ± 63.4 U/L vs 24.7 ± 9.3 U/L, P < 0.05; AST 228.1 ± 25.4 U/L vs 32.7 ± 6.8 U/L, P < 0.05). Severe pain occurred in three patients, which was controlled with morphine and fentanyl.
CONCLUSION: TACE combined with immediate RFA is a safe and effective treatment for large solitary HCCs. Severe pain is a major side effect, but can be controlled by morphine.
Large hepatocellular carcinoma; Transcatheter arterial chemoembolisation; Radiofrequency ablation; Combination therapy; Synchronism
Budd–Chiari syndrome (BCS) often leads to hepatocellular carcinoma (HCC). Transcatheter arterial chemoembolization (TACE) has been increasingly used to treat BCS patients with HCC. The purposes of this study were to illustrate imaging features in BCS patients with HCC, and to analyze the effects of TACE on BCS patients with HCC.
246 consecutive patients with primary BCS were retrospectively studied. 14 BCS patients with HCC were included in this study. BCS were treated with angioplasty and/or stenting, and HCC were managed with TACE. Imaging features on ultrasonography, CT, MRI, and angiography and the serum AFP level were analyzed.
Inferior vena cava block and stricture of hepatic venous outflow tract more frequently occurred. Portal vein invasion was found in only 2 patients (14.2%). Imaging studies showed that most nodules of HCC were near the edge of liver, irregular, more than 3 cm in diameter, heterogeneous mass and solitary (≤3 nodules). HCC in patients associated with BCS was isointense or hypointense in nonenhanced CT images, and exhibited heterogeneous enhancement during the arterial phase and washout during the portal venous phase on enhanced CT and MRI. The serum AFP level significantly declined after TACE treatment.
BCS patients with inferior vena cava block and stricture of hepatic venous outflow tract seems to be associated with HCC. A single, large, irregular nodule with a peripheral location appears to be HCC. TACE can effectively treat HCC in BCS patients.
Hepatocellular carcinoma; Budd–Chiari syndrome; Transcatheter arterial chemoembolization
Developing sensors for in vivo chemical monitoring is a daunting challenge. An alternative approach is to couple sampling methods with online analytical techniques; however, such approaches are generally hampered by lower temporal resolution and slow analysis. In this work, microdialysis sampling was coupled with segmented flow electrospray ionization mass spectrometry (ESI-MS) to perform in vivo chemical monitoring. Use of segmented flow to prevent Taylor dispersion of collected zones and rapid analysis with direct ESI-MS allowed 5 s temporal resolution to be achieved. The MS “sensor” was applied to monitoring acetylcholine in the brain of live rats. The detection limit of 5 nM was sufficient to monitor basal acetylcholine as well as dynamic changes elicited by microinjection of neostigmine, an inhibitor of acetycholinesterase that evoked rapid increases in acetycholine, and tetrodotoxin, a blocker of Na+ channels, that lowered the acetylcholine concentration. The versatility of the sensor was demonstrated by simultaneously monitoring metabolites and infused drugs.
Pleural tuberculosis (TB), together with lymphatic TB, constitutes more than half of all extrapulmonary cases. Pleural effusions (PEs) in TB are representative of lymphocytic PEs which are dominated by T cells. However, the mechanism underlying T lymphocytes homing and accumulation in PEs is still incompletely understood. Here we performed a comparative analysis of cytokine abundance in PEs from TB patients and non-TB patients by protein array analysis and observed that MCP-2/CCL8 is highly expressed in the TB-PEs as compared to peripheral blood. Meanwhile, we observed that CCR5, the primary receptor used by MCP-2/CCL8, is mostly expressed on pleural CD4+ T lymphocytes. Furthermore, we found that infection with either Mycobacterium bovis Bacillus Calmette-Guérin (BCG) or Mycobacterium tuberculosis H37Rv induced production of MCP-2/CCL8 at both transcriptional and protein level in Raw264.7 and THP-1 macrophage cells, mouse peritoneal macrophages as well as human PBMC monocyte-derived macrophages (MDMs). The induction of MCP-2/CCL8 by mycobacteria is dependent on the activation of TLR2/PI3K/Akt and p38 signaling pathway. We conclude that accumulation of MCP-2/CCL8 in TB-PEs may function as a biomarker for TB diagnosis.
Stimulated by a recent experimental report, charge transfer and photophysical properties of donor-acceptor ambipolar polymer were studied with the quantum chemistry calculation and the developed 3D charge difference density method. The effects of electronic acceptor strength on the structure, energy levels, electron density distribution, ionization potentials, and electron affinities were also obtained to estimate the transporting ability of hole and electron. With the developed 3D charge difference density, one visualizes the charge transfer process, distinguishes the role of molecular units, and finds the relationship between the role of DPP and excitation energy for the three polymers during photo-excitation.
In vivo neurochemical monitoring using microdialysis sampling is important in neuroscience because it allows correlation of neurotransmission with behavior, disease state, and drug concentrations in the intact brain. A significant limitation of current practice is that different assays are utilized for measuring each class of neurotransmitter. We present a high performance liquid chromatography (HPLC) - tandem mass spectrometry method that utilizes benzoyl chloride for determination of the most common low molecular weight neurotransmitters and metabolites. In this method, 17 analytes were separated in 8 minutes. The limit of detection was 0.03–0.2 nM for monoamine neurotransmitters, 0.05–11 nM for monoamine metabolites, 2–250 nM for amino acids, 0.5 nM for acetylcholine, 2 nM for histamine, and 25 nM for adenosine at sample volume of 5 µL. Relative standard deviation for repeated analysis at concentrations expected in vivo averaged 7% (n = 3). Commercially available 13C benzoyl chloride was used to generate isotope-labeled internal standards for improved quantification. To demonstrate utility of the method for study of small brain regions, the GABAA receptor antagonist bicuculline (50 µM) was infused into rat ventral tegmental area while recording neurotransmitter concentration locally and in nucleus accumbens, revealing complex GABAergic control over mesolimbic processes. To demonstrate high temporal resolution monitoring, samples were collected every 60 s while neostigmine, an acetylcholine esterase inhibitor, was infused into the medial prefrontal cortex. This experiment revealed selective positive control of acetylcholine over cortical glutamate.
Neurotransmitter; Microdialysis; Benzoylation; Liquid Chromatography; Mass Spectrometry
Pallidal dopamine, GABA and the endogenous opioid peptides enkephalins have independently been shown to be important controllers of sensorimotor processes. Using in vivo microdialysis coupled to liquid chromatography-mass spectrometry (LC-MS) and a behavioral assay, we explored the interaction between these three neurotransmitters in the rat globus pallidus. Amphetamine (3 mg/kg i.p.) evoked an increase in dopamine, GABA and methionine/leucine enkephalin. Local perfusion of the dopamine D1 receptor antagonist SCH 23390 (100 μM) fully prevented amphetamine stimulated enkephalin and GABA release in the globus pallidus and greatly suppressed hyperlocomotion. In contrast, the dopamine D2 receptor antagonist raclopride (100 μM) had only minimal effects suggesting a greater role for pallidal D1 over D2 receptors in the regulation of movement. Under basal conditions, opioid receptor blockade by naloxone perfusion (10 μM) in the globus pallidus stimulated GABA and inhibited dopamine release. Amphetamine-stimulated dopamine release and locomotor activation were attenuated by naloxone perfusion with no effect on GABA. These findings demonstrate a functional relationship between pallidal dopamine, GABA and enkephalin systems in the control of locomotor behavior under basal and stimulated conditions. Moreover, these findings demonstrate the usefulness of LC-MS as an analytical tool when coupled to in vivo microdialysis.
Globus pallidus; dopamine; enkephalins; mass spectrometry; microdialysis; amphetamine
An adaptive mesh refinement strategy is proposed in this paper for the Immersed Boundary and Immersed Interface methods for two-dimensional elliptic interface problems involving singular sources. The interface is represented by the zero level set of a Lipschitz function φ(x,y). Our adaptive mesh refinement is done within a small tube of |φ(x,y)|≤ δ with finer Cartesian meshes. The discrete linear system of equations is solved by a multigrid solver. The AMR methods could obtain solutions with accuracy that is similar to those on a uniform fine grid by distributing the mesh more economically, therefore, reduce the size of the linear system of the equations. Numerical examples presented show the efficiency of the grid refinement strategy.
Adaptive mesh refinement; immersed boundary method; immersed interface method; elliptic interface problem; Cartesian grid method; level set representation; singular sources
A method is presented to solve two-phase problems involving soluble surfactants. The incompressible Navier–Stokes equations are solved along with equations for the bulk and interfacial surfactant concentrations. A non-linear equation of state is used to relate the surface tension to the interfacial surfactant concentration. The method is based on the use of a diffuse interface, which allows a simple implementation using standard finite difference or finite element techniques. Here, finite difference methods on a block-structured adaptive grid are used, and the resulting equations are solved using a non-linear multigrid method. Results are presented for a drop in shear flow in both 2D and 3D, and the effect of solubility is discussed.
Multiphase flows; interfacial dynamics; surfactant; soluble surfactant; surface phase; bulk phase; adsorption; desorption; complex geometry; diffuse interface; phase field; multigrid; adaptive grid; finite difference
Off-line analysis and characterization of samples separated by capillary liquid chromatography (LC) has been problematic using conventional approaches to fraction collection. We demonstrate collection of nanoliter fractions by forming plugs of effluent from a 75 μm inner diameter LC column segmented by an immiscible oil such as perfluorodecalin. The plugs are stored in tubing that can then be used to manipulate the samples. Off-line electrospray ionization mass spectrometry (ESI-MS) was used to characterize the samples. ESI-MS was performed by directly pumping the segmented plugs into a nanospray emitter tip. Critical parameters including the choice of oils, ESI voltage, and flow rates that allows successful direct infusion analysis were investigated. Best signals were obtained under conditions in which the oil did not form an electrospray but was siphoned away from the tip. Off-line analysis showed preservation of the chromatogram with no loss of resolution. The method was demonstrated to allow changes in flow rate during the analysis. Specifically, decreases in flow rate were used to allow extended MS analysis time on selected fractions, similar to “peak parking”.
AIM: To present a series of cases with life-threatening hemorrhage from ruptured hepatic artery pseudoaneurysm after pancreaticoduodenectomy (PD) treated with placement of stent-grafts.
METHODS: Massive hemorrhage from ruptured hepatic artery pseudoaneurysm after PD in 9 patients (6 men, 3 women) at the age of 23-75 years (mean 48 years), were treated with placement of percutaneous endovascular balloon-expandable coronary stent-grafts. All patients were not suitable for embolization because of a non-patent portal vein. One or more stent-grafts, ranging 3-6 mm in diameter and 16-55 mm in length, were placed to exclude ruptured pseudoaneurysm. Follow-up data, including clinical condition, liver function tests, and Doppler ultrasound examination, were recorded at the outpatient clinic.
RESULTS: Immediate technical success was achieved in all the 9 patients. All stent-grafts were deployed in the intended position for immediate cessation of bleeding and preservation of satisfactory hepatic arterial blood flow. No significant procedure-related complications occurred. Recurrent bleeding occurred in 2 patients at 16 and 24 h, respectively, after placement of stent-grafts and treated with surgical revision. One patient died of sepsis 12 d after the interventional procedure. The remaining 6 patients were survived when they were discharged. The mean follow-up time was 10.5 mo (range 4-16 mo). No patient had recurrent bleeding after discharge. Doppler ultrasound examination verified the patency of hepatic artery and stent-grafts during the follow-up.
CONCLUSION: Placement of stent-grafts is an effective and safe procedure for acute life-threatening hemorrhage from ruptured hepatic artery pseudoaneurysm.
Pancreaticoduodenectomy; Hemorrhage; Hepatic artery; Pseudoaneurysm; Stent-graft
Objective: To assess the feasibility and effectiveness of transjugular intrahepatic route aspiration thrombectomy and catheter-directed thrombolytic therapy in patients with acute superior mesenteric venous thrombosis. Materials and methods: During a period of 8 years, 12 patients with acute thrombosis of the superior mesenteric vein (SMV) were treated by transjugular intrahepatic approach. The mean age was 41.2 years. After access to the portal system via the transjugular approach, the pigtail catheter fragmentation of the thrombus, local urokinase injection, and manual aspiration thrombectomy were used for treatment of the SMV thrombosis initially, followed by continuous thrombolytic therapy via an indwelling infusion catheter in the SMV, which was performed for 2 to 6 days (4.2 ± 1.8 days). The adequacy of anticoagulation was performed during treatment, throughout hospitalization, and after discharge. Results: Technical success was achieved in all 12 patients. Substantial clinical improvement was seen in these patients after the procedure. Minor complications at the jugular puncture site were observed in 4 patients, but the thrombolytic therapy was not interrupted. Contrast-enhanced computed tomography (CT) scan before discharge demonstrated nearly complete disappearance of SMV thrombosis in all patients. The 12 patients were discharged 5–10 days (7.6 ± 2.0) after admission. Mean duration of follow-up after hospital discharge was 37.7 months, and no recurrent episodes of SMV thrombosis developed during that time period. Conclusion: Catheter-directed thrombus aspiration, mechanical fragmentation, and local thrombolytic infusion via the transjugular intrahepatic route is a safe and effective therapy for the management of patients with acute symptomatic SMV thrombosis.
Superior mesenteric vein; Thrombosis; Thrombolysis; Mechanical thrombectomy; Interventional radiology
NAD+ is a coenzyme for hydride transfer enzymes and a substrate for sirtuins and other NAD+-dependent ADPribose transfer enzymes. In wild-type Saccharomyces cerevisiae, calorie restriction accomplished by glucose limitation extends replicative lifespan in a manner that depends on Sir2 and the NAD+ salvage enzymes, nicotinic acid phosphoribosyl transferase and nicotinamidase. Though alterations in the NAD+ to nicotinamide ratio and the NAD+ to NADH ratio are anticipated by models to account for the effects of calorie restriction, the nature of a putative change in NAD+ metabolism requires analytical definition and quantification of the key metabolites.
Hydrophilic interaction chromatography followed by tandem electrospray mass spectrometry were used to identify the 12 compounds that constitute the core NAD+ metabolome and 6 related nucleosides and nucleotides. Whereas yeast extract and nicotinic acid increase net NAD+ synthesis in a manner that can account for extended lifespan, glucose restriction does not alter NAD+ or nicotinamide levels in ways that would increase Sir2 activity.
The results constrain the possible mechanisms by which calorie restriction may regulate Sir2 and suggest that provision of vitamins and calorie restriction extend lifespan by different mechanisms.
AIM: To summarize our methods and experience with interventional treatment for symptomatic acute-subacute portal vein and superior mesenteric vein thrombosis (PV-SMV) thrombosis.
METHODS: Forty-six patients (30 males, 16 females, aged 17-68 years) with symptomatic acute-subacute portal and superior mesenteric vein thrombosis were accurately diagnosed with Doppler ultrasound scans, computed tomography and magnetic resonance imaging. They were treated with interventional therapy, including direct thrombolysis (26 cases through a transjugular intrahepatic portosystemic shunt; 6 through percutaneous transhepatic portal vein cannulation) and indirect thrombolysis (10 through the femoral artery to superior mesenteric artery catheterization; 4 through the radial artery to superior mesenteric artery catheterization).
RESULTS: The blood reperfusion of PV-SMV was achieved completely or partially in 34 patients 3-13 d after thrombolysis. In 11 patients there was no PV-SMV blood reperfusion but the number of collateral vessels increased significantly. Symptoms in these 45 patients were improved dramatically without severe operational complications. In 1 patient, the thrombi did not respond to the interventional treatment and resulted in intestinal necrosis, which required surgical treatment. In 3 patients with interventional treatment, thrombi re-formed 1, 3 and 4 mo after treatment. In these 3 patients, indirect PV-SMV thrombolysis was performed again and was successful.
CONCLUSION: Interventional treatment, including direct or indirect PV-SMV thrombolysis, is a safe and effective method for patients with symptomatic acute-subacute PV-SMV thrombosis.
Portal thrombosis; Superior mesenteric vein thrombosis; Thrombolysis; Interventional treatment
In the structure of the title complex, [Cu(C8H4O4)(C12H8N2)(H2O)]·C3H7NO, the CuII ion is pentacoordinated in a distorted square-pyramidal geometry by two O atoms of a 3-formyl-2-oxidobenzoate dianion and two N atoms of a 1,10-phenanthroline ligand occupying the basal plane and a water O atom located at the apical site. The structure displays O—H⋯O hydrogen bonding and intermolecular π–π stacking interactions between 1,10-phenantroline ligands [interplanar distance of 3.448 (5) Å].
Phytochemical-mediated modulation of p-glycoprotein (P-gp) and other drug transporters may underlie many herb-drug interactions. Serial plasma concentration-time profiles of the P-gp substrate, digoxin, were used to determine whether supplementation with milk thistle or black cohosh modified P-gp activity in vivo. Sixteen healthy volunteers were randomly assigned to receive a standardized milk thistle (900 mg daily) or black cohosh (40 mg daily) supplement for 14 days, followed by a 30-day washout period. Subjects were also randomized to receive rifampin (600 mg daily, 7 days) and clarithromycin (1000 mg daily, 7 days) as positive controls for P-gp induction and inhibition, respectively. Digoxin (Lanoxicaps®, 0.4 mg) was administered orally before and at the end of each supplementation and control period. Serial digoxin plasma concentrations were obtained over 24 hours and analyzed by chemiluminescent immunoassay. Comparisons of AUC(0–3), AUC(0–24), Cmax,, CL/F, and elimination half-life were used to assess the effects of milk thistle, black cohosh, rifampin, and clarithromycin on digoxin pharmacokinetics. Rifampin produced significant reductions (p<0.01) in AUC(0–3), AUC(0–24) and Cmax, while clarithromycin increased these parameters significantly (p<0.01). Significant changes in digoxin half-life and CL/F were also observed with clarithromycin. No statistically significant effects on digoxin pharmacokinetics were observed following supplementation with either milk thistle or black cohosh, although digoxin AUC(0–3) and AUC(0–24) approached significance (p=0.06) following milk thistle administration. When compared to rifampin and clarithromycin, supplementation with these specific formulations of milk thistle or black cohosh did not appear to affect digoxin pharmacokinetics, suggesting that these supplements are not potent modulators of P-gp in vivo.