[Show abstract][Hide abstract] ABSTRACT: A novel sensitive and selective LC-MS/MS method for the determination of agomelatine, 7-desmethyl-agomelatine and 3-hydroxy-agomelatine in human plasma was developed and validated. After simple protein precipitation, the analytes were separated on a Phenomenex ODS3 column (4.6×150 mm, 5μm, Phenomenex, USA) with mobile phase consisted of methanol and 5mM ammonium formate solution (containing 0.2% formic acid) at a ratio of 70:30 (v/v) with a flow rate of 0.8mL/min. The MS acquisition was performed in multiple reactions monitoring (MRM) mode with a positive electrospray ionization source. The mass transitions monitored were m/z 244.1→185.1, m/z 230.1→171.1, m/z 260.1→201.1 and m/z 180.1→110.1 for agomelatine, 7-desmethyl-agomelatine, 3-hydroxy-agomelatine and internal standard (phenacetin), respectively. The method was validated for specificity, linearity and lower limit of quantification, precision and accuracy, extraction recovery, matrix effect and stability. The calibration curves for agomelatine, 7-desmethyl-agomelatine and 3-hydroxy-agomelatine in human plasma were linear over concentration ranges of 0.0457-100ng/mL, 0.1372-300ng/mL and 0.4572-1000ng/mL, respectively. Intra- and inter-day precisions and accuracies data met the acceptance criteria of FDA guideline for bioanalytical method validation. The developed method has been successfully applied to a bioequivalence study in healthy Chinese volunteers.
Journal of chromatography. B, Analytical technologies in the biomedical and life sciences 09/2015; 1003:60-66. DOI:10.1016/j.jchromb.2015.09.018 · 2.73 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Background:
Some studies have investigated the effects of polymorphisms in the vascular endothelial growth factor (VEGF) gene on responsiveness to chemotherapy for colorectal cancer (CRC) and have shown inconclusive results.
Eligible studies that assessed the associations between polymorphisms in the VEGF gene and response to chemotherapy in CRC were searched in the PubMed, Embase and Medline databases until November 2014. Odds ratios (OR) and 95% confidence intervals (CIs) were used to evaluate the associations, using Review Manager software, version 5.3. Stratified analysis was also conducted.
In the overall analysis, a significant association with responsiveness to chemotherapy in CRC was identified in CC vs. CA of the VEGF -2578 C/A polymorphism (OR = 1.40, 95% CI 1.00-1.97, P = 0.05) and in CC+CT vs. TT of the VEGF -460 C/T polymorphism (OR = 0.71, 95% CI 0.53-0.96, P = 0.02). In subgroup analysis, a significant association was found in excluding anti-angiogenic agent subgroup in three comparison models of the VEGF -2578 C/A polymorphism and another three genetic models of the VEGF -460 C/T C/A polymorphism.
CC vs. CA of the VEGF -2578 C/A polymorphism and CC+CT vs. TT of the VEGF -460 C/T polymorphism might be predictive factors of responsiveness to chemotherapy in CRC. However, single-nucleotide polymorphisms in the VEGF gene lacked sufficient predictive ability to determine whether patients with CRC should add anti-angiogenic agents to their chemotherapy regimens.
PLoS ONE 05/2015; 10(5):e0126619. DOI:10.1371/journal.pone.0126619 · 3.23 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Conventional ways to produce microfluidic devices cost a lot due to the requirements for cleanroom environments and expensive equipment, which prevents the wider applications of microfluidics in academia and in industry. In this paper, a dry film photoresist was utilized in a simple way to reduce the fabrication cost of microfluidic masters. Thus, a fast prototyping and fabrication of microstructures in polydimethylsiloxane microchips through a replica molding technology was achieved in a low-cost setting within 2.5 h. Subsequently, major manufacturing conditions were optimized to acquire well-resolved microfluidic molds, and the replicated microchips were validated to be of good performance. A T-junction channel microchip was fabricated by using a dry film master to generate water droplets of uniform target size. Meanwhile, a gated injection of fluorescein sodium and a contactless conductivity detection of Na+ were both performed in a crosslink channel microchip via capillary electrophoresis, in other words, this fast prototyping and fabrication method would be an efficient, economical way to embody structural design into microfluidic chips for various applications.
[Show abstract][Hide abstract] ABSTRACT: IntroductionThe miR-183/-96/-182 cluster is a conserved polycistronic microRNA (miRNA) cluster which is highly expressed in most breast cancers. Although there are some sporadic reports which demonstrate the importance of each miRNA in this cluster in breast cancer, the biological roles of this cluster as a whole and its regulation mechanisms in breast cancer are still unclear. We compared the expression of this cluster in different cancer types, analyzed the regulation mechanism of this cluster, identified new target genes, and examined the impact of this cluster on breast cancer cells.Methods
The miRNA level was detected by LNA-based northern blot and Real-time PCR, and was also analyzed from TCGA dataset. Bioinformatics research and luciferase assay were applied to find the promoter regions and transcription factors. To investigate the biological effects of the miR-183/-96 /-182 cluster in breast cancer, we generated miR-96, miR-182 and miR-183 overexpression stable cell lines to check the overdose effects; we also used miR-Down¿ antagomir for each miRNA as well as miR-183/-96 /-182 cluster sponge lentivirus to check the knockdown effects. Growth, migration, cell cycle profile and survival of these cells was then monitored by colony formation assay, MTT assay, cell wound healing assay, flow cytometry and microscopy. The target gene was validated by Real-time PCR, luciferase assay, Western blot and Phalloidin/DAPI counterstaining.ResultsThe miR-183/-96/-182 cluster was highly expressed in most breast cancers, and its transcription is disordered in breast cancer. The miR-183/-96/-182 cluster was transcribed in the same pri-miRNA and its transcription was regulated by ZEB1 and HSF2. It increased breast cell growth by promoting more rapid completion of mitosis, promoted cell migration and was essential for cell survival. MiR-183 targeted the RAB21 mRNA directly in breast cancer.Conclusion
The miR-183/-96/-182 cluster is up-regulated in most breast cancer. It functions as an oncogene in breast cancer as it increases cell proliferation and migration.
Breast cancer research: BCR 11/2014; 16(6):473. DOI:10.1186/s13058-014-0473-z · 5.49 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The present study examined the agreement between in vitro dissolution f2 similarity and in vivo bioequivalence criteria for BCS class II drugs. Dissolution test profiles were generated using the First-order model with varied dissolution parameters around the standard values of a reference profile. The in vivo curves were derived from in vitro dissolution profiles with the drug's pharmacokinetics parameters by numerical convolution method. The Cmax, Tmax, AUC0-t and AUC0-∞ obtained from in vivo test and reference concentration-time curves were compared, and the CmaxR (Cmax ratio), TmaxDif (Tmax difference), AUC0-tR (AUC0-t ratio) and AUC0-∞R (AUC0-∞ ratio) were determined. The relationships between CmaxR, AUC0-tR, AUC0-∞R, f2 and the First-order model parameters demonstrated that the Similarity Region 1 enclosed by the f2 contour line labeled 50 was completely within the Bioequivalence Region enclosed by the contour lines labeled 0.80 and 1.20 of AUC0-tR, AUC0-∞R, and CmaxR, and the Similarity Region 2 enclosed by the f2 contour line labeled 35 was nearly overlapped with the Bioequivalence Region, but did not exactly match. The results indicate that the public standard for in vitro dissolution f2 similarity criterion (f2⩾50) is probably slightly conservative and may be widened to an appropriate lower critical value.
European journal of pharmaceutical sciences: official journal of the European Federation for Pharmaceutical Sciences 10/2014; 66. DOI:10.1016/j.ejps.2014.10.002 · 3.35 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Unlabelled:
Defective autophagy is implicated in the pathogenesis of nonalcoholic fatty liver diseases (NAFLD) through poorly defined mechanisms. Cardiolipin is a mitochondrial phospholipid required for bioenergetics and mitophagy from yeast to mammals. Here we investigated a role for ALCAT1 in the development of NAFLD. ALCAT1 is a lysocardiolipin acyltransferase that catalyzes pathological cardiolipin remodeling in several aging-related diseases. We show that the onset of diet-induced NAFLD caused autophagic arrest in hepatocytes, leading to oxidative stress, mitochondrial dysfunction, and insulin resistance. In contrast, targeted deletion of ALCAT1 in mice prevented the onset of NAFLD. ALCAT1 deficiency also restored mitophagy, mitochondrial architecture, mitochondrial DNA (mtDNA) fidelity, and oxidative phosphorylation. In support of a causative role of the enzyme in a mitochondrial etiology of the disease, hepatic ALCAT1 expression was significantly up-regulated in mouse models of NAFLD.
Forced expression of ALCAT1 in primary hepatocytes led to multiple defects that are highly reminiscent of NAFLD, including steatosis, defective autophagy, and mitochondrial dysfunction, linking pathological cardiolipin remodeling by ALCAT1 to the pathogenesis of NAFLD.
[Show abstract][Hide abstract] ABSTRACT: Benfotiamine is a lipid-soluble thiamine precursor which can transform to thiamine in vivo and subsequently be metabolized to thiamine monophosphate (TMP) and thiamine diphosphate (TDP). This study investigated the pharmacokinetic profiles of thiamine and its phosphorylated metabolites after single- and multiple-dose administration of benfotiamine in healthy Chinese volunteers, and assessed the bioavailability of orally benfotiamine administration compared to thiamine hydrochloride. In addition, concentration of hippuric acid in urine which is produced in the transformation process of benfotiamine was determined. The results showed that thiamine and its phosphorylated metabolites exhibited different pharmacokinetic characteristics in plasma, blood and erythrocyte, and one-compartment model provided the best fit for pharmacokinetic profiles of thiamine. The transformation process of benfotiamine to thiamine produced large amount of hippuric acid. No accumulation of hippuric acid was observed after multiple-dose of benfotiamine. Compared to thiamine hydrochloride, the bioavailability of thiamine in plasma and TDP in erythrocyte after oral administration of benfotiamine were 1147.3 ± 490.3% and 195.8 ± 33.8%, respectively. The absorption rate and extent of benfotiamine systemic availability of thiamine were significantly increased indicating higher bioavailability of thiamine from oral dose of benfotiamine compared to oral dose of thiamine hydrochloride.
The Journal of Clinical Pharmacology 06/2014; 54(6). DOI:10.1002/jcph.261 · 2.48 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: A simple, sensitive and cost-effective assay based on reversed phase high performance liquid chromatography (RP-HPLC) with isocratic mode for simultaneous determination of bendamustine (BM) and its active metabolite, gamma-hydroxy-bendamustine (γ-OH-BM) in human plasma and urine was developed and validated. Sample preparation involved protein precipitation by 10% perchloric acid-methanol solution. The peaks were recorded by using fluorescence detector (excitation wavelength 328nm and emission wavelength 420nm). The calibration curves were linear over concentration ranges of 8.192-10,000ngmL(-1) and 5-1000ngmL(-1) for BM in human plasma and urine as well as 10-1000ngmL(-1) and 5-1000ngmL(-1) for γ-OH-BM in human plasma and urine, respectively. Intra- and inter-run precisions of BM and γ-OH-BM were less than 15% and the bias were within ±15% for both plasma and urine. This validated method was successfully applied to a pharmacokinetic study enrolling 10 Chinese patients with indolent B-cell non-Hodgkin lymphoma and chronic lymphocytic leukemia administered a single intravenous infusion of 100mgm(2) bendamustine hydrochloride.
Journal of chromatography. B, Analytical technologies in the biomedical and life sciences 04/2014; 960C:98-104. DOI:10.1016/j.jchromb.2014.04.027 · 2.73 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Hypothesis:
Simotinib hydrochloride (SIM6802), which is a new epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI), is often prescribed for cancer patients with comorbidities and has serious adverse effects on gastrointestinal physiology. The drug-drug interactions (DDIs) between simotinib and other drugs in combination and the underlying mechanism of its gastrointestinal toxicity remain unclear. We hypothesized that the DDIs and the gastrointestinal toxicity of simotinib were related to its effects on the permeability of the intestine.
To determine the intestinal absorption capacity, pharmacokinetic studies and an in situ loop assay were used. The intestinal permeability was measured by a Caco-2 Transwell model. Real time PCR and Western blots were applied to detecting the expression changes of cell junction genes.
Our research demonstrated that simotinib upregulated the absorption of cefaclor, valaciclovir and acyclovir. The increase of non-selective absorption was caused by the low expression of cell junction gene afadin-6 and the increase in paracellular permeability in intestinal epithelial cells after simotinib treatment.
These findings revealed that simotinib upregulated intestinal absorption by increasing the paracellular permeability of intestinal epithelial cells. Our research provides theoretical bases for better formulation of EGFR-TKIs to alleviate adverse gastrointestinal effects and also provides guidance for clinical administration of simotinib.
Drug Metabolism and Pharmacokinetics 02/2014; 29(4). DOI:10.2133/dmpk.DMPK-13-RG-123 · 2.57 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: A simple, sensitive and cost-effective assay based on reversed phase high performance liquid chromatography (RP-HPLC) with isocratic mode for simultaneous determination of bendamustine (BM) and its active metabolite, gamma-hydroxy-bendamustine (γ-OH-BM) in human plasma and urine was developed and validated. Sample preparation involved protein precipitation by 10% perchloric acid-methanol solution. The peaks were recorded by using fluorescence detector (excitation wavelength 328 nm and emission wavelength 420 nm). The calibration curves were linear over concentration ranges of 8.192-10,000 ng·mL−1 and 5-1000 ng·mL−1 for BM in human plasma and urine as well as 10-1000 ng·mL−1 and 5-1000 ng·mL−1 for γ-OH-BM in human plasma and urine, respectively. Intra- and inter-run precisions of BM and γ-OH-BM were less than 15% and the bias were within ±15% for both plasma and urine. This validated method was successfully applied to a pharmacokinetic study enrolling 10 Chinese patients with indolent B-cell non-Hodgkin lymphoma and chronic lymphocytic leukemia administered a single intravenous infusion of 100 mg·m2 bendamustine hydrochloride.
[Show abstract][Hide abstract] ABSTRACT: Simotinib is a novel epidermal growth factor receptor tyrosine kinase inhibitor. This study presented a sensitive and specific liquid chromatography-electrospray ionization-mass spectrometry method using erlotinib as internal standard for the determination of simotinib in human plasma. The method involved a simple liquid-liquid extraction using diethyl ether. The analytes were separated with isocratic gradient elution on an Agilent TC-C18 column (4.6×150mm, 5μm). Mass spectrometric detector equipped with electrospray ionization source was carried out in the mode of multiple reaction monitoring (MRM). The monitored transitions were m/z 501.2→182.1 for simotinib and m/z 394.4→278.1 for erlotinib. The calibration curve of simotinib was established over the range of 2.058-3000μgL(-1) (r(2)=0.9924). The intra- and inter-day precisions were all less than 10%, and all the biases were not more than 7%. This validated method was then successfully applied to a pharmacokinetic study involving twelve healthy Chinese volunteers. The mean Cmax and Tmax for simotinib were 254.79±98.30 μgL(-1) and 1.71±0.48 h, respectively. Plasma concentrations declined with a t1/2 of 5.37±2.32 h. AUC0-t and AUC0→∞ values obtained were 1262.59±501.41 μgL(-1)h and 1329.95±517.42 μgL(-1)h, respectively.
Journal of chromatography. B, Analytical technologies in the biomedical and life sciences 12/2013; 947-948C:168-172. DOI:10.1016/j.jchromb.2013.12.021 · 2.73 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: A rapid, specific and sensitive HPLC–MS/MS method was developed and validated for the determination of 20(S)-protopanaxadiol (PPD) in human plasma. PPD and the internal standard PD were extracted from plasma by liquid–liquid extraction with cyclohexane–methylene dichloride (2:1, v/v). The separation was performed on a HyPURIYTY C18 column using methanol–5 mM ammonium formate (90:10, v/v) as mobile phase at a flow rate of 0.35 mL/min. Mass spectrometric detection was carried out by electrospray ionization (ESI) in the positive ion mode using multiple reaction monitoring (MRM). The monitored transitions were m/z 425.4→217.2 for PPD and at m/z 461.4→425.5 for PD. The method was linear over the range 0.512–100 ng/mL with a lower limit of quantification (LLOQ) of 0.512 ng/mL. The mean extraction recovery of PPD was greater than 78.2% and no significant matrix effect was detected. The intra- and inter-day precisions were less than 10% and the biases below 4% for PPD. The validated method was applied to a three-level single-dose clinical pharmacokinetics study of 12 healthy Chinese volunteers and the main pharmacokinetic parameters of PPD were obtained.
[Show abstract][Hide abstract] ABSTRACT: Illegal chemicals, which could cause unpredictable side effects, may be added into traditional Chinese medicine (TCM) for a rapid healing effect. In this report, a surface-enhanced Raman scattering (SERS) analysis method for five kinds of illegally added drugs (rosiglitazone maleate, phenformin hydrochloride, metformin hydrochloride, pioglitazone hydrochloride and sibutramine hydrochloride) in Chinese traditional patent medicine (CTPM) has been demonstrated, including simultaneous detections of drug mixtures with CTPM. Silver colloidal, prepared by a sodium citrate reaction, was used as a SERS substrate. The optimum pH condition for each drug has also been explored because of its combined effect on protonation, surface charge, repulsion of an analyte and nanoparticles. Furthermore, the simultaneous detection of two or three kinds of these chemicals has been carried out. Characteristic peaks are employed for qualitative analysis. This is the first research using SERS for the analysis of drug mixtures in CTPM without any separation process.
[Show abstract][Hide abstract] ABSTRACT: A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the determination of uric acid in human plasma was developed and validated. Separation was achieved on a C18 column by the mobile phase of 30% water (containing 0.5% formic acid) and 70% methanol. Quantification was done using a multiple reaction monitoring (MRM) mode to monitor the precursor-to-product ion transitions of m/z 169.1 → m/z 141.1 for uric acid and m/z 171 → m/z 143 for 1,3-(15)N uric acid (IS) at a positive ionization mode. The calibration curve was established over the range of 0.4096 - 100 mg/L, and the correlation coefficient was better than 0.99. The intra-day and inter-day relative standard deviations were less than 5.1%. The accuracy determined at three concentrations ranged between 92.7 and 102.3%. This method was successfully applied to an efficacy study of intravenous recombinant urate oxidase produced by Escherichia coli in a clinical phase I study.
[Show abstract][Hide abstract] ABSTRACT: The research about biological molecules with an appropriate analysis method is very significant for the development of life science. Equilibrium gradient separation technology is a developing method which is explored for the analysis of biological macromolecules including peptides, protein, nucleic acids (DNA and RNA), and so on. It combines separation and concentration by using an electrophoretic force and an opposing hydrodynamic force to create a stable equilibrium point on which analytes can focus. Therefore, different analytes can be focused on different equilibrium point. Since the establishment of equilibrium gradient separation technology at the end of the 1980s, a family of this technology has been developed. And each one has its own characteristic with the utilization of different theory to form a gradient (in pH, electric field, conductivity, temperature, etc.), which finally induce a gradient in electrophoretic force. This paper briefly introduces the development of equilibrium gradient separation technology and prospects for the future of this technology. And the representative technologies including counteracting chromatographic electrophoresis technology, conductivity gradient focusing technology, temperature gradient focusing technology, electric-field gradient focusing technology, dynamic field gradient focusing technology and bipolar electrode focusing technology are presented.
[Show abstract][Hide abstract] ABSTRACT: A novel, simple and reliable bioanalytical method of high performance liquid chromatography for simultaneous quantification of nelarabine and its active metabolite 9-β-d-arabinofuranosyl-guanine (Ara-G) in human plasma was developed and validated. The calibration curves for nelarabine and Ara-G were linear over concentration ranges of 0.1562–10 and 0.6250–40 μg mL−1, respectively. Intra- and inter-day precision and accuracy results satisfied the acceptable criteria for bioanalytical method validation. This method has been applied to a pharmacokinetic study involving 20 T-cell lymphoblastic leukemia/lymphoma patients.
[Show abstract][Hide abstract] ABSTRACT: Oxidative stress causes mitochondrial dysfunction and heart failure through unknown mechanisms. Cardiolipin (CL), a mitochondrial membrane phospholipid required for oxidative phosphorylation, plays a pivotal role in cardiac function. The onset of age-related heart diseases is characterized by aberrant CL acyl composition that is highly sensitive to oxidative damage, leading to CL peroxidation and mitochondrial dysfunction. Here we report a key role of ALCAT1, a lysocardiolipin acyltransferase that catalyzes the synthesis of CL with a high peroxidation index, in mitochondrial dysfunction associated with hypertrophic cardiomyopathy. We show that ALCAT1 expression was potently upregulated by the onset of hyperthyroid cardiomyopathy, leading to oxidative stress and mitochondrial dysfunction. Accordingly, overexpression of ALCAT1 in H9c2 cardiac cells caused severe oxidative stress, lipid peroxidation, and mitochondrial DNA (mtDNA) depletion. Conversely, ablation of ALCAT1 prevented the onset of T4-induced cardiomyopathy and cardiac dysfunction. ALCAT1 deficiency also mitigated oxidative stress, insulin resistance, and mitochondrial dysfunction by improving mitochondrial quality control through upregulation of PINK1, a mitochondrial GTPase required for mitochondrial autophagy. Together, these findings implicate a key role of ALCAT1 as the missing link between oxidative stress and mitochondrial dysfunction in the etiology of age-related heart diseases.