[Show abstract][Hide abstract] ABSTRACT: 5-Hydroxytryptamine (5-HT) is a powerful constrictor of coronary arteries and is considered to be involved in the pathophysiological mechanisms of coronary-artery spasm. However, the mechanism of enhancement of coronary-artery constriction to 5-HT during the development of coronary artery disease remains to be elucidated. Organ culture of intact blood-vessel segments has been suggested as a model for the phenotypic changes of smooth muscle cells in cardiovascular disease.
PLoS ONE 01/2014; 9(9):e107128. · 3.53 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Ranolazine is mainly used to treat patients with chronic stable angina in clinical practice. However, ranolazine does not lower significantly systemic blood pressure. The direct effect of ranolazine on vascular tone remains unknown. In the present study, we investigated the vascular effects and mechanisms of action of ranolazine in isolated rat intrarenal arteries. Rings of intrarenal arteries were mounted in a small vessel myography using two stainless steel wires for the measurement of isometric tension. L-type Ca²⁺ currents were recorded in isolated single renal arterial smooth muscle cells using patch clamp techniques in whole-cell mode. Ranolazine induced concentration-dependent relaxations in rings contracted with phenylephrine, but ranolazine failed to cause any relaxation in rings pre-contracted by U46619, 5-HT or endothelin-1. Ranolazine also induced relaxations in norepinephrine pre-contracted rings. Yohimbine failed to induce relaxation in rings pre-contracted by norepinephrine. Propranolol did not affect ranolazine-induced relaxation but the relaxant effect of ranolazine was much less than that of prazosin. Ranolazine-induced relaxations were slight but significantly attenuated by endothelial denudation. Partial inhibition was observed in endothelium-intact arteries exposed to a combination of iberiotoxin and apamin. Ranolazine at higher concentration (>30 μM) inhibited Ca²⁺-induced contraction in a noncompetitive manner. Ranolazine reduced L-type Ca²⁺ currents at potentials between -30 and 50 mV in isolated renal artery myocytes. Therefore it can be said that ranolazine has significant α₁-adrenergic receptor and weak calcium channel antagonistic effects in rat intrarenal arteries.
European journal of pharmacology 03/2012; 683(1-3):211-6. · 2.59 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The renin-angiotensin system (RAS) is regarded as one of the most important regulatory systems for cardiovascular homeostasis. In this study, we investigated associations of the five genetic polymorphisms in the RAS and presence of coronary artery disease (CAD) in type 2 diabetes.
Genotyping was performed by polymerase chain reaction-restriction fragment length polymorphism analysis. We used the generalised multifactor dimensionality reduction (GMDR) method to identify gene-gene interactions.
The D allele in the ACE gene was significantly more frequent in type 2 diabetic patients with CAD (p = 0.04). In multivariate logistic regression analysis, the DD genotype was associated with a significantly increased risk of CAD (p = 0.044). 1675G/A variant in the AT2R gene was found to be associated with CAD in female subjects with type 2 diabetes (p = 0.025). The three other polymorphisms of the RAS do not seem to influence the development of CAD in type 2 diabetes. No significant gene-gene interaction for any combinations of genotypes was found in the GMDR method.
The DD variant of the ACE gene polymorphism is associated with increased risk of developing CAD in Chinese patients with type 2 diabetes. A slight impact of AT2R 1675G/A polymorphism on CAD was found only in female diabetic patients.
Journal of Renin-Angiotensin-Aldosterone System 02/2012; 13(2):305-13. · 2.29 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: 1. It has been reported that allitridi, an active compound extracted from garlic, has many cardiovascular effects. However, it remains unknown whether allitridi affects major repolarization currents, such as the transient outward K(+) current (I(to) ), ultrarapid delayed rectifier K(+) current (I(Kur)) and the L-type Ca(2+) current (I(Ca)), in human atrial myocytes. 2. In the present study, we investigated the effects of allitridi on I(to), I(Kur), I(Ca) and the action potential in human isolated atrial myocytes using the whole-cell patch recording technique. 3. Allitridi reversibly inhibited I(to), but not I(Kur) and I(Ca), in human atrial myocytes. These effects of allitridi on I(to) were concentration dependent (IC(50) = 44.9 μmol/L). Inactivation of I(to) was accelerated and the voltage-dependent inactivation potential was shifted towards the negative direction. Allitridi (30 μmol/L) significantly prolonged action potential duration in human atrial myocytes. 4. The results of the present study indicate that allitridi inhibits I(to), but not I(Kur) and I(Ca), and prolongs the action potential duration in human atrial myocytes.
Clinical and Experimental Pharmacology and Physiology 03/2011; 38(5):323-7. · 2.41 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: A sensitive and rapid method based on liquid chromatography- tandem mass spectrometry (MS-MS) was developed for the determination of olopatadine in human plasma. Sample preparations were carried out by protein precipitation with the addition of acetonitrile followed by liquid-liquid extraction with ethyl acetate/dichloromethane after internal standard (IS, amitriptyline) spiked. After evaporation to dryness, the resultant residue was reconstituted in mobile phase. Separation of olopatadine and IS from the interferences was achieved on a C(18) column followed by MS-MS detection. The analytes were monitored in the positive ionization mode with a TurboIonspray source. Multiple reaction monitoring using the transition of m/z 338 → 165 and m/z 278 → 91 was performed to quantify olopatadine and IS, respectively. The method had a total chromatographic run time of 3.5 min and linear calibration curves over the concentration range of 0.2-100 ng/mL. The lower limit of quantification was 0.2 ng/mL. For each QC concentration level the intra- and interday precisions were less than 11.4%, and relative errors ranged between -6.40% and 9.26%. The validated method was successfully applied to the quantification of olopatadine concentration in human plasma after administration of olopatadine at an oral dose of 5 mg in order to evaluate the pharmacokinetics.
Journal of analytical toxicology 03/2011; 35(2):113-8. · 2.11 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: A sensitive and rapid method was developed for quantification of olprinone in human plasma utilizing liquid chromatography tandem mass spectrometry (LC-MS/MS). An aliquot of 1 mL plasma sample was extracted with ethyl acetate-dichloromethane. Separation of olprinone and the milrinone (internal standard, IS) from the interferences was achieved on a C(18) column followed by MS/MS detection. The analytes were monitored in the positive ionization mode. Multiple reaction monitoring using the transition of m/z 251 → m/z 155 and m/z 212 → m/z 140 was performed to quantify olprinone and IS, respectively. The method had a total chromatographic run time of 3 min and linear calibration curves over the concentration range of 0.5-60 ng/mL. The lower limit of quantification (LLOQ) was 0.5 ng/mL. The intra- and inter-day precisions were less than 16.3% for low QC level, and 7.1% for other QC levels, respectively. The intra- and inter-day relative errors were ranged between -12.2% and 3.7% for three QC concentration levels. The validated method was successfully applied to the quantification of olprinone concentration in human plasma after intravenous (i.v.) administration of olprinone at a constant rate of infusion of 2 μg/(kg min) for 5 min in order to evaluate the pharmacokinetics.
Journal of pharmaceutical and biomedical analysis 01/2011; 54(1):198-202. · 2.45 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: To investigate the effect of matrine on proliferation of vascular smooth muscle cells (VSMCs) and elucidate the underlying mechanisms.
Rat aortic VSMCs were cultured in medium supplemented with 10% fetal bovine serum and treated with various concentrations (0, 5, 10, 15, and 20 mg/L) of matrine for 72 h. VSMCs proliferation and cell cycle profiling were assessed using a methylene blue incorporation assay and flow cytometry, respectively. The underlying protein signaling mechanisms were determined using Western blot analysis of the expression levels of cell cycle regulatory genes, including p53, p21, p27, cyclin D1, cyclin E, cyclin-dependent kinase 2 and 4 (cdk2, cdk4), and phosphorylated Rb. The involvement of p21 and p27 pathways was further determined using small interfering RNA (siRNA) knockdown.
Matrine inhibited VSMC proliferation in a dose-dependent manner by promoting G(1) arrest. The G(1) arrest was accompanied by up-regulation of p53 and p21 protein levels, and down-regulation of cyclin D1/cdk4, cyclin E/cdk2 and phosphorylated Rb protein levels. Matrine did not affect p27 expression. Furthermore, the anti-proliferative effect of matrine was abolished by silencing of p21, but not by silencing of p27.
Our data indicate that matrine has an inhibitory effect on VSMC proliferation via up-regulation of the p53/p21 signaling pathway and modulation of other cell cycle regulatory genes.
[Show abstract][Hide abstract] ABSTRACT: A rapid, selective and highly sensitive high performance liquid chromatography-tandem mass spectrometry method (LC-MS/MS) was developed and validated for the determination and pharmacokinetic investigation of eptifibatide in human plasma. Eptifibatide and the internal standard (IS), EPM-05, were extracted from plasma samples using solid phase extraction. Chromatographic separation was performed on a C(18) column at a flow rate of 0.5 mL/min. Detection of eptifibatide and the IS was achieved by tandem mass spectrometry with an electrospray ionization (ESI) interface in positive ion mode. Traditional multiple reaction monitoring (MRM) using the transition of m/z 832.6-->m/z 646.4 and m/z 931.6-->m/z 159.4 was performed to quantify eptifibatide and the IS, respectively. The calibration curves were linear over the range of 1-1000 ng/mL with the lower limit of quantitation validated at 1 ng/mL. The intra- and inter-day precisions were within 13.3%, while the accuracy was within +/-7.6% of nominal values. The validated LC-MS/MS method was successfully applied for the evaluation of pharmacokinetic parameters of eptifibatide after intravenous (i.v.) administration of a 45 microg/kg bolus of eptifibatide to 8 healthy volunteers.
Journal of chromatography. B, Analytical technologies in the biomedical and life sciences 08/2010; 878(23):2094-100. · 2.78 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: MicroRNAs (miRNAs) have been increasingly reported to have important roles in diverse biological and pathological processes. We investigated miR-1 and miR-206 expression and their potential roles in a rat model of myocardial infarction (MI). miR-1 and miR-206 expression were significantly increased, and insulin-like growth factor 1 (IGF-1) protein was markedly reduced without obvious change of its mRNA level after MI induction. Position 175-196 of rat IGF-1 3'-untranslated region was identified to be required for efficient downregulation by miR-1/miR-206. IGF-1 level was reduced without changing its transcript level in rat H9C2 myoblast cells modified with miR-1 (H9C2-miR-1). In the serum withdrawal and hypoxic condition, caspase-3 activity and mitochondrial potential were significantly increased in H9C2-miR-1 cells compared with the control group, respectively (p<0.05, p<0.01). Together, our results indicate that miR-1 and miR-206 are involved in apoptotic cell death in MI by post-transcriptional repression of IGF-1.
Biochemical and Biophysical Research Communications 02/2009; 381(4):597-601. · 2.28 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: A rapid and sensitive quantitative assay method was developed for determining ribavirin pharmacokinetic in human plasma. The chromatographic separation was achieved within 4.5 min using a SinoChrom ODS-BP column (4.6 x 150 mm, 5 microm) with acetonitrile-water (1 mmol/L ammonium acetate buffer, 0.1% formic acid; 15:85, v/v) at a constant flow rate of 0.8 mL/min. The MRM pairs were m/z 245.2 --> m/z 113.1 for ribavirin and m/z 226.1 --> m/z 152.1 for acyclovir (internal standard), respectively, with dwell times of 200 ms for each transition. The results showed calibration curve for ribavirin was linear over a concentration range of 1-1000 ng/mL. The lower limit of quantification (LLOQ) was 1 ng/mL ribavirin. Twenty healthy volunteers received a 300 mg oral dose of ribavirin. Blood samples were then collected up to 120 h postdosing. All plasma data were comodeled for ribavirin by using noncompartmental modeling. The single dose of ribavirin was well tolerated and no serious adverse effects occurred. The mean time to maximum concentration was about 1.25 h. The mean maximum concentration of drug in plasma for oral ribavirin was 250 ng/mL. The mean elimination half-life was 43.6 h. The present study describes a simple, specific, sensitive HPLC-MS/MS method for measuring plasma drug concentration and analyzing human pharmacokinetics of ribavirin.
[Show abstract][Hide abstract] ABSTRACT: To construct an eukaryotic expression vector for miRNA-1-2 that can be expressed in rat H9C2 cardiomyocytes.
The precursor miRNA (pre-miRNA) DNA template for miRNA-1-2 was designed and generated by PCR amplification. The DNA template was inserted into the hairpin RNA expression vector pSilence-4.1-neo and identified by DNA sequencing analysis. The recombinant plasmid DNA was then transfected into H9C2 cells via Lipofectamine, and the green fluorescence protein expression vector pEGFP-N3 served as the transfection marker. Twenty-four hours after transfection, the total cellular RNA was extracted using TRIzol reagent, and thermoscript reverse transcriptase (RT)-PCR was performed to determine miRNA-1-2 precursor expression.
DNA sequencing indicated that the miR-1-2 expression plasmid was correctly constructed. The precursor miRNA-1-2 was successfully expressed in the H9C2 cells, and the expression of Hand2 protein could be efficiently inhibited by miRNA-1.
Nan fang yi ke da xue xue bao = Journal of Southern Medical University 10/2008; 28(9):1559-61, 1567.
[Show abstract][Hide abstract] ABSTRACT: To investigate the effect of adenoviral vector infection on the differentiation potential of human bone marrow mesenchymal stem cells (hMSCs).
The third-passage hMSCs were infected with the recombinant adenovirus expressing green fluorescence protein (GFP) for 2, 4, 8 and 16 days. RT-PCR was used to detect the mRNA expression of endodermal marker CYP 51, mesodermal marker SM22alpha, ectodermal marker nestin, pluripotent marker oct-4 and the alternative splicing factor nPTB. Seven days after adenovirus infection, the hMSCs were cultured in the presence of adipogenic agents for 14 days, and the adipose cells differentiated from hMSCs were detected with oil red O staining.
Compared with normal hMSCs, the cell infected with the adenovirus for 2, 4, 8 and 16 days showed no obvious down-regulation of CYP51, SM22alpha, nestin, OCT4 or nPTB. The hMSCs 7 days after adenovirus infection were induced to differentiate into adipose cells, with a similar differentiation rate to that of normal hMSCs. CONCLUSION The differentiation potential of hMSCs is not affected by adenovirus infection, suggesting that adenovirus can be used as the gene delivery vector in MSC differentiation studies.
Nan fang yi ke da xue xue bao = Journal of Southern Medical University 08/2008; 28(7):1132-5.
[Show abstract][Hide abstract] ABSTRACT: 1. Ketamine is widely used for the induction of anaesthesia in high-risk patients with cardiovascular instability or severe hypovolaemia. However, the ionic mechanisms involved in the effects of ketamine at therapeutically relevant concentrations in human cardiac myocytes are unclear. The present study was designed to investigate the effects of ketamine on L-type Ca2+ (I(Ca)), transient outward K+ (I(to)), ultra-rapid delayed rectifier K+ (I(Kur)) and inward rectifier potassium (I(K1)) currents, as well as on action potentials, in human isolated atrial myocytes. 2. Atrial myocytes were isolated enzymatically from specimens of human atrial appendage obtained from patients undergoing coronary artery bypass grafting. The action potential and membrane currents were recorded in both current- and voltage-clamp modes using the patch-clamp technique. 3. Ketamine inhibited I(Ca) with an IC(50) of 1.8 micromol/L. In addition, 10 micromol/L ketamine decreased the I(Ca) peak current at +10 mV from 5.1 +/- 0.3 to 2.1 +/- 0.4 pA/pF (P < 0.01), but did not change the threshold potential, peak current potential and reverse potential. 4. Ketamine had no effect on I(to), I(Kur) or I(K1), but it reversibly shortened the duration of the action potential in human atrial myocytes. 5. In conclusion, ketamine, at a clinically relevant concentration, shortens the action potential duration of the human atrial myocytes, probably by inhibiting I(Ca).
Clinical and Experimental Pharmacology and Physiology 07/2008; 35(12):1465-70. · 2.41 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: A high-performance liquid chromatography method with fluorescence detection (HPLC-FLD) for the determination of levofloxacin in human plasma is described. Neutralized with phosphate buffer (pH 7.0), the sample (0.1 mL) was extracted with dichlormethane (1 mL). After voltex-mixing and centrifuged at 3000g for 6 min at 4 degrees C, the upper aqueous layer was aspirated using a micro vacuum pump and the organic layer was directly transferred to a clean test tube without pipetting. The organic solvent was evaporated and the residues were reconstituted with the mobile phase. Levofloxacin and terazosin (internal standard, IS) were chromatographically separated on a C(18) column with a mobile phase containing phosphate buffer (pH 3.0, 10 mm), acetonitrile and triethylamine (76:24:0.076, v/v/v) at a flow rate of 1 mL/min. The analytes were detected using fluorescence detection at an excitation and emission wavelength of 295 and 440 nm, respectively. The linear range of the calibration curves was 0.0521-5.213 microg/mL for levofloxacin with a lower limit of quantitation (0.0521 microg/mL). The retention times of levofloxacin and terazosin were 2.5 and 3.1 min, respectively. Within- and between-run precision was less than 12 and 11%, respectively. Accuracy ranged from -6.3 to 4.5%. The recovery ranged from 86 to 89% at the concentrations of 0.0521, 0.5213 and 5.213 microg/mL. The present HPLC-FLD method is sensitive, efficient and reliable. The method described herein has been successfully used for the pharmacokinetic and bioequivalence studies of a levofloxacin formulation product after oral administration to healthy Chinese volunteers.
[Show abstract][Hide abstract] ABSTRACT: To study the multiple dose clinical pharmacokinetics of risperidone and its main active metabolite, 9-hydroxyrisperidone, in Chinese female patients with schizophrenia.
The subjects were 23 Chinese female inpatients aged 18-65 years who met the CCMD-III (third revision of the Chinese Criteria of Mental Disorders) criteria for schizophrenia. Subjects were tested after 17 d of treatment with 2 mg risperidone twice daily. Plasma concentrations of risperidone and 9-hydroxy-risperidone were assayed by using validated high performance liquid chromatography-mass spectrometry (HPLC-MS) methods.
Risperidone was rapidly absorbed (Tmax was 1.6 h) and its T1/2 in plasma was short (3.2 h). 9-hydroxy-risperidone was quickly metabolized from the parent drug with a mean Tmax of 2.5 h. It had a long half-life of 24.7 h. The C(ss)(av) of risperidone and 9-hydroxy-risperidone were 36.9+/-33.1 and 110.6+/-30.5 microg x h x L(-1), respectively, and the AUC(ss)0-12 were 443.2+/- 397.4 and 1327.2+/- 402.3 microg x h x L(-1), respectively. CL/F and V/F of risperidone were 8.7+/- 6.2 L/h and 34.1+/- 24.3 L, respectively. Interindividual variations for pharmacokinetic parameters were quite large for risperidone. All 23 subjects experienced high prolactin levels when treated with risperidone. However there was no correlation between prolactin level and the concentration of risperidone, 9-hydroxy-risperidone, or the active moiety.
Risperidone showed large interindividual variations in pharmacokinetics. Administration of risperidone resulted in high serum prolactin levels. The results indicate that systemic exposure to risperidone and 9-hydroxy-risperidone in female Chinese schizophrenic patients is higher relative to published data for white Caucasian patients. Larger studies regarding the PK/PD relationship may be required to develop a reasonable clinical dosage regimen for Chinese female patients.