Chicoric acid (CA) induces autophagy in gastric cancer through promoting endoplasmic reticulum (ER) stress regulated by AMPK.

Gastric cancer is one of the most common cancers leading to tumor-related deaths worldwide. Chicoric acid (CA) exhibits a variety of protective effects in different diseases. However, its role in regulating tumor progression has not been reported. Autophagy, as a conserved catabolic process, sustains cellular homoeostasis responding to stress to modulate cell fate. In the study, the effects of CA on gastric cancer were investigated. The results indicated that CA treatment markedly reduced the cell viability and induced apoptosis in gastric cancer cells, and prevented tumor growth in an established xenograft gastric cancer model. Furthermore, CA exposure significantly induced autophagy both in gastric cancer cells and tumor samples, as evidenced by the up-regulated expression of LC3II. Moreover, phosphorylated AMP-activated protein kinase (AMPK) and p70S6 kinase (p70s6k) expression were obviously promoted by CA in vitro and in vivo. Importantly, blocking AMPK activation abrogated CA-induced expression of LC3II in gastric cancer cells. In addition, endoplasmic reticulum (ER) stress in tumor samples or cells was markedly induced by CA treatment through promoting the expression of associated signals such as Parkin, protein kinase RNA-like ER kinase (PERK), activating transcription factors 4 (ATF4) and ATF6. Importantly, these effects were abolished by the inhibition of AMPK signaling. Collectively, our findings indicated that CA prevents human gastric cancer progression by inducing autophagy partly through the activation of AMPK, and represents an effective therapeutic strategy against gastric cancer development.

Simultaneous determination of curcumin diethyl disuccinate and its active metabolite curcumin in rat plasma by LC-MS/MS: Application of esterase inhibitors in the stabilization of an ester-containing prodrug.

Four esterase inhibitors, ethylenediamine tetraacetic acid disodium (Na2EDTA), sodium fluoride (NaF), bis(4-nitrophenyl) phosphate (BNPP) and phenylmethanesulfonyl fluoride (PMSF), were evaluated for their inhibitory effects on enzymatic hydrolysis of labile phenolate esters in curcumin diethyl disuccinate (CDD), a prodrug of curcumin (CUR), in rat plasma. BNPP and PMSF at 10mM exhibited stabilization by preventing degradation of CDD. BNPP at a final concentration of 10mM was subsequently selected to prevent ex vivo metabolism of CDD throughout LC-MS/MS analysis of CDD and CUR in rat plasma. A simple protein precipitation technique using acetonitrile as a precipitating agent was used to extract CDD, CUR and dimethylcurcumin (DMC), an internal standard, from rat plasma. Chromatographic separation was performed on a Halo C8 column (4.6×50mm, 2.7µm) using an isocratic mobile phase containing acetonitrile-0.2% formic acid in water (73:27v/v) with a flow rate of 0.4mLmin(-1). An AB SCIEX QTRAP(®) 6500 mass spectrometer was operated using a positive ion electrospray mode for ionization and detection of analytes and internal standard. Calibration curves for CDD and CUR were established using 50µL of rat plasma over the concentration range of 1-500ngmL(-1). The developed method was fully validated according to US Food and Drug Administration (FDA) guidelines for selectivity, sensitivity, linearity, accuracy, precision, dilution integrity, recovery, matrix effect, and stability. The validated method was applied to evaluate the pharmacokinetics of CDD and CUR in rats after a single intravenous dose of 40mgkg(-1). The method using BNPP as an esterase inhibitor was successful in determining the remaining CDD in rat plasma. The pharmacokinetic results indicate that CDD in rats is converted instantaneously to CUR after intravenous administration and a higher CUR plasma concentration at 5min is achieved in comparison with direct intravenous injection of CUR.

Simultaneous determination and pharmacokinetic study of four phenol compounds in rat plasma by ultra-high performance liquid chromatography with tandem mass spectrometry after oral administration of Echinacea purpurea extract.

A rapid and sensitive assay based on ultra-high performance liquid chromatography with electrospray ionization tandem mass spectrometry was established and validated for the simultaneous determination of cichoric acid, chlorogenic acid, quinic acid, and caffeic acid in rat plasma after oral administration of Echinacea purpurea extract using butylparaben as the internal standard. Samples were pretreated by liquid-liquid extraction with ethyl acetate. The separations for analytes were performed on an ACQUITY UPLC HSS C18 column (1.8 µm 2.1 × 100 mm) using a gradient elution program with acetonitrile/10 mM ammonium acetate (pH 5.6) at a flow rate of 0.3 mL/min. The analytes were detected in multiple reaction monitoring mode with negative electrospray ionization. The lower limit of quantification of each analyte was not higher than 10.85 ng/mL. The relative standard deviation of the intraday and interday precisions was less than 14.69%. The relative errors of accuracies were in the range of -13.80 to 14.91%. The mean recoveries for extraction recovery and matrix effect were higher than 80.79 and 89.98%, respectively. The method validation results demonstrated that the proposed method was sensitive, specific, and reliable, which was successfully applied to the pharmacokinetic study of four components after oral administration of Echinacea purpurea extract.

A Novel Simultaneous Determination of Sarpogrelate and its Active Metabolite (M-1) in Human Plasma, Using Liquid Chromatography-Tandem Mass Spectrometry: Clinical Application.

BACKGROUND: This study describes a novel analytical method for simultaneously determining sarpogrelate and its metabolite (M-1) in human plasma, using liquid chromatography coupled with tandem mass spectrometry, with electrospray ionization in the positive ion mode. METHODS: Sarpogrelate, M-1, and labeled internal standard (d3-sarpogrelate) were extracted from 50 µL of human plasma by simple protein precipitation. Chromatographic separation was performed by using a linear gradient elution of a mobile phase involving water-formic acid (99.9:0.1, v/v) and acetonitrile-formic acid (99.9:0.1, v/v) over 4 min of run time on a column, with a core-shell-type stationary phase (Kinetex C18, 50 mm×2.1 mm i.d., 2.6-µm particle size, Phenomenex, USA). Detection of the column effluent was performed by using a triple-quadruple mass spectrometer in the multiple-reaction monitoring mode. RESULTS: The developed method was validated in human plasma, with lower limits of quantification of 10 ng/mL for sarpogrelate and 2 ng/mL for M-1. The calibration curves of sarpogrelate and M-1 were linear over the concentration ranges of 10-2,000 and 2-400 ng/mL, respectively (R(2)>0.99). The carry-over effect, precision, accuracy, and stability of the method met the criteria for acceptance. CONCLUSIONS: A simple, fast, robust, and reliable analytical method was successfully developed and applied to the high-throughput determination of sarpogrelate and its metabolite in real plasma samples in a pharmacokinetic study of healthy subjects.

Simultaneous determination of sarpogrelate and its active metabolite in human plasma by liquid chromatography with tandem mass spectrometry and its application to a pharmacokinetic study.

We established a rapid and simple liquid chromatography with tandem mass spectrometry method for the simultaneous determination of sarpogrelate and its active metabolite, M-1, in human plasma. Sarpogrelate, M-1, and the internal standard, ketanserin, were extracted from a 50 µL aliquot of human plasma by protein precipitation using acetonitrile. Chromatographic separation was performed on a Shim-pack GIS ODS C18 column (100 × 3.0 mm; 3 µm) with an isocratic mobile phase consisting of 10 mM ammonium acetate and acetonitrile (70:30, v/v) at a flow rate of 0.6 mL/min; the total run time was <2.5 min. Mass spectrometric detection was conducted in selected reaction-monitoring mode with positive electrospray ionization at m/z 430.35 → 135.10 for sarpogrelate, m/z 330.30 → 58.10 for M-1, and m/z 395.70 → 188.85 for ketanserin. The linear ranges of concentration for sarpogrelate and M-1 were 1-1000 and 0.5-500 ng/mL, respectively. The coefficient of variation for the assay's precision was ≤9.95%, and the accuracy was 90.6-107%. All analytes were stable under various storage and handling conditions, and no relevant crosstalk and matrix effect was observed. This method was successfully applied to a pharmacokinetic study after oral administration of a 100 mg sarpogrelate tablet to healthy male Korean volunteers.

Determination of 12 potential nephrotoxicity biomarkers in rat serum and urine by liquid chromatography with mass spectrometry and its application to renal failure induced by Semen Strychni.

In previous nephrotoxicity metabonomic studies, several potential biomarkers were found and evaluated. To investigate the relationship between the nephrotoxicity biomarkers and the therapeutic role of Radix Glycyrrhizae extract on Semen Strychni-induced renal failure, 12 typical biomarkers are selected and a simple LC-MS method has been developed and validated. Citric acid, guanidinosuccinic acid, taurine, guanidinoacetic acid, uric acid, creatinine, hippuric acid, xanthurenic acid, kynurenic acid, 3-indoxyl sulfate, indole-3-acetic acid, and phenaceturic acid were separated by a Phenomenex Luna C18 column and a methanol/water (5 mM ammonium acetate) gradient program with a runtime of 20 min. The prepared calibration curves showed good linearity with regression coefficients all above 0.9913. The absolute recoveries of analytes from serum and urine were all more than 70.4%. With the developed method, analytes were successfully determined in serum and urine samples within 52 days. Results showed that guanidinosuccinic acid, guanidinoacetic acid, 3-indoxyl sulfate, and indole-3-acetic acid (only in urine) were more sensitive than the conventional renal function markers in evaluating the therapeutic role of Radix Glycyrrhizae extract on Semen Strychni-induced renal failure. The method could be further used in predicting and monitoring renal failure cause by other reasons in the following researches.

Development and validation of two liquid chromatography-tandem mass spectrometry methods for the determination of silibinin and silibinin hemisuccinate in human plasma.

To investigate the pharmacokinetics of silibinin and silibinin hemisuccinate in human plasma, two high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) methods were developed and validated. The methods require a small volume of sample (100µL), and the recovery of the analytes was complete with a good reproducibility (CV% 1.7-9.5), after a simple protein precipitation. Naringenin was used as internal standard. The chromatographic methods provided a good separation of diastereoisomers A and B of both silibinin and silibinin hemisuccinate onto a Chromolith Performance RP18e 100mm×3mm column, with a resolution of peaks from plasma matrix in less than 6min. The methods precision values expressed as CV% were always ≤6.2% and the accuracy was always well within the acceptable 15% range. Quantification was performed on a triple-quadrupole tandem mass spectrometer by Selected Reaction Monitoring (SRM) mode, in a negative ion mode, via electrospray ionization (ESI). The lower limit of quantitation was set at 5.0ng/mL (silibinin) and 25.0ng/mL (silibinin hemisuccinate), and the linearity was validated up to 1000.0 and 12,500.0ng/mL, for silibinin and silibinin hemisuccinate, respectively, with correlation coefficients (R(2)) of 0.991 or better. The methods were suitable for pharmacokinetic studies and were successfully applied to human plasma samples from subjects treated intravenously with Legalon(®) SIL at the dose of 20mg/kg, expressed as silibinin.

Pharmacokinetics of guanidinosuccinic acid in rat blood and cerebrospinal fluid.

  Guanidinosuccinic acid (GSA) is a uremic toxin, and its excess accumulation in the CSF under uremic conditions is thought to produce neural excitotoxicity. It is important to understand the manner of GSA distribution/elimination from the circulating blood and CSF and its alteration in the presence of renal failure. The purpose of this study was to evaluate the kinetics of GSA in the circulating blood using a rat model of cisplatin-induced renal failure and GSA transport between the circulating blood and CSF. The AUCinf and t1/2 of GSA in cisplatin-treated rats were approximately 7-fold greater than those in normal rats. The CLtot of GSA in cisplatin-treated rats was reduced by 88% compared with normal rats, whereas the Vss of GSA did not differ between normal and cisplatin-treated rats. These results suggest that the renal elimination of GSA is attenuated in cisplatin-treated rats. In normal rats, the elimination clearance of GSA from the CSF (15.5 µL/(min·rat)) was found to be 88-fold greater than its blood-to-CSF influx clearance (0.176 µL/(min·rat)). Thus, the greater elimination clearance of GSA from the CSF, compared with the influx clearance, may contribute to the maintenance of a low GSA concentration in the CSF.

[Experimental study of dicholine succinate pharmacokinetics].

We have conducted for the first time an experimental study of pharmacokinetics of dicholine succinate (DCS) for different ways of its administration in rats The quantitative evaluation of DCS and its metabolites was performed by the radioactive isotope technique. Various parameters of DCS pharmacokinetics were estimated, including the dose dependence of drug content in the blood plasma, total bioavailability, distribution kinetics, and the main ways of DCS excretion.

A liquid chromatography-tandem mass spectrometric method for the simultaneous quantitation of five components of Ixeris sonchifoliain (Bge.) Hance in rat plasma and its application to a pharmacokinetic study.

A rapid and sensitive liquid chromatography-tandem mass spectrometric (LC-MS/MS) method for the simultaneous quantitation of five major active ingredients of Ixeris sonchifolia (Bge.) Hance in rat plasma has been developed and validated. After liquid-liquid extraction of 50µL plasma with ethyl acetate, analytes and internal standard (I.S.), astilbin, were chromatographed on a Zorbax SB-C18 column (150mm×4.6mm, 5µm) using acetonitrile - 10mM ammonium acetate (60:40, v/v, pH 5.6) as mobile phase. The five analytes: chicoric acid, luteolin 7-O-ß-d-glucuronide, luteolin 7-O-ß-d-glucopyranoside, luteolin 7-O-ß-d-glucopyranosyl-(1→2)-ß-d-glucopyranoside, apigenin 7-O-ß-d-glucuronide and I.S., were detected by negative ion electrospray ionization followed by multiple reaction monitoring of the ions with m/z 473.0→311.0, 461.0→285.0, 447.0→285.0, 609.1→285.0, 445.1→269.0 and 449.1→150.9, respectively. The method was linear for all analytes in the concentration range 10-3000ng/mL with intra- and inter-day precision (as relative standard deviation) ≤8.99% and accuracy (as relative error) ≤4.00%. The limits of detection (LOD) were 5, 1, 5, 5, 2ng/mL for chicoric acid, luteolin 7-O-ß-d-glucuronide, luteolin 7-O-ß-d-glucopyranoside, luteolin 7-O-ß-d-glucopyranosyl-(1→2)-ß-d-glucopyranoside, apigenin 7-O-ß-d-glucuronide, respectively. The method was successfully applied to a pharmacokinetic study of the five analytes in rat after a single intravenous dose of Kudiezi Injection.

Effect of food intake on the pharmacokinetics of sarpogrelate and its active metabolite following oral administration to beagle dogs.

1. The objectives of this study were to develop a pharmacokinetic model for sarpogrelate and its metabolite M-1 and to identify the effect of food on sarpogrelate and M-1 pharmacokinetics in beagle dogs. 2. A single 100 mg oral dose of sarpogrelate was administered to fasted and fed beagle dogs and the plasma concentrations of sarpogrelate and M-1 were measured simultaneously by liquid chromatography tandem mass spectrometry. The resultant data were analyzed by modeling approaches using ADAPT5. 3. The plasma concentration time course of sarpogrelate and M-1 were described using a parent-metabolite compartment model with first-order absorption and elimination. The systemic exposure of sarpogrelate and its metabolite after the administration of a single 100 mg oral dose was significantly decreased under the fed condition compared to that under the fasting condition. Modeling approaches have sufficiently explained the food effect of sarpogrelate, i.e. an increased Vc and decreased Ka, in fed dogs. The food effect of sarpogrelate was due to its pH-dependent dissolution. 4. These findings suggest that food intake affects both the rate and extent of absorption of sarpogrelate, and that the pharmacological effect of sarpogrelate can differ significantly according to food intake.

Comparison of pharmacokinetics between sarpogrelate hydrochloride immediate-release formulation and controlled-release formulation.

OBJECTIVE: Sarpogrelate hydrochloride is a selective 5-hydroxytryptamine receptor subtype 2A (5HT(2A)) antagonist that blocks serotonin-induced platelet aggregation. The aim of this study was to compare the pharmacokinetics of sarpogrelate and its metabolite after dosing with a controlledrelease (CR) formulation or an immediaterelease (IR) formulation. METHODS: In this open-label, 2-period, 2-treatment crossover study, 36 healthy male subjects were evenly allocated to two groups in a sequence-randomized manner. In the first period, the first group received 100-mg sarpogrelate IR 3 times at a 6-h interval, and the second group received 300-mg sarpogrelate CR once. After a 7-day washout, the two groups switched their dosing schedule. Serial blood sampling was performed up to 24 hours after the first drug administration during each period. Plasma concentrations of sarpogrelate and its metabolite (M-1) were measured using liquid chromatography-tandem mass spectrometry. Pharmacokinetic parameters were calculated by noncompartmental methods. RESULTS: There were no significant differences between two formulations in the pharmacokinetic properties in the time to reach maximum plasma concentration (C(max)) of sarpogrelate and its metabolite. The CR-to-IR geometric mean ratios, as measured by area under the plasma concentration-time curve (AUC) were 1.31 (90% confidence interval, 1.22 - 1.41) for sarpogrelate and 1.21 (1.14 - 1.29) for M-1. The C(max) was 0.98 (0.85 - 1.12) for sarpogrelate and 1.07 (0.96 - 1.19) for M-1. CONCLUSIONS: After the administration of sarpogrelate hydrochloride CR and IR formulations using the same daily dose, AUCs were slightly higher for the CR formulation than for the IR formulation for both sarpogrelate and its metabolite M-1, but the C(max) values were similar.

Biochemical, molecular, and clinical characteristics of children with short chain acyl-CoA dehydrogenase deficiency detected by newborn screening in California.

BACKGROUND: Short-chain acyl-CoA dehydrogenase deficiency (SCADD) is an autosomal recessive inborn error of mitochondrial fatty acid oxidation with highly variable biochemical, genetic, and clinical characteristics. SCADD has been associated with accumulation of butyryl-CoA byproducts, including butyrylcarnitine (C4), butyrylglycine, ethylmalonic acid (EMA), and methylsuccinic acid (MS) in body fluid and tissues. Differences in genotype frequencies have been shown between patients diagnosed clinically versus those diagnosed by newborn screening. Moreover, while patients diagnosed clinically have a variable clinical presentation including developmental delay, ketotic hypoglycemia, epilepsy and behavioral disorders, studies suggest patients diagnosed by newborn screening are largely asymptomatic. Scant information is published about the biochemical, genetic and clinical outcome of SCADD patients diagnosed by newborn screening. METHODS: We collected California newborn screening, follow-up biochemical levels, and ACADS mutation data from September, 2005 through April, 2010. We retrospectively reviewed available data on SCADD cases diagnosed by newborn screening for clinical outcomes. RESULTS: During the study period, 2,632,058 newborns were screened and 76 confirmed SCADD cases were identified. No correlations between initial C4 value and follow-up biochemical markers (C4, EMA or MS levels) were found in the 76 cases studied. We found significant correlation between urine EMA versus MS, and correlation between follow-up C4 versus urine EMA. Of 22 cases where ACADS gene sequencing was performed: 7 had two or more deleterious mutations; 8 were compound heterozygotes for a deleterious mutation and common variant; 7 were homozygous for the common variant c.625G>A; and 1 was heterozygous for c.625G>A. Significant increases in mean urine EMA and MS levels were noted in patients with two or more deleterious mutations versus mutation heterozygotes or common polymorphism homozygotes. Clinical outcome data was available in 31 patients with follow-up extending from 0.5 to 60 months. None developed epilepsy or behavioral disorders, and three patients had isolated speech delay. Hypoglycemia occurred in two patients, both in the neonatal period. The first patient had concomitant meconium aspiration; the other presented with central apnea, poor feeding, and hypotonia. The latter, a c.625G>A homozygote, has had persistent elevations in both short- and medium-chain acylcarnitines; diagnostic workup in this case is extensive and ongoing. CONCLUSIONS: This study examines the largest series to date of SCADD patients identified by newborn screening. Our results suggest that confirmatory tests may be useful to differentiate patients with common variants from those with deleterious mutations. This study also provides evidence to suggest that, even when associated with deleterious mutations, SCADD diagnosed by newborn screening presents largely as a benign condition.

Synthesis, transport and mechanism of a type I prodrug: L-carnitine ester of prednisolone.

Aerosol glucocorticoid medications have become more and more important in treating BA (bronchial asthma). Although these agents are dosed to directly target airway inflammation, adrenocortical suppression and other systematic effects are still seen. To tackle this problem in a novel way, two L-carnitine ester derivatives of prednisolone (as the model drug), namely, PDC and PDSC, were synthesized to increase the absorption of prednisolone across the human bronchial epithelial BEAS-2B cells by the organic cation/carnitine transporter OCTN2 (SLC22A5) and then to slowly and intracellularly release prednisolone. The transport of prednisolone, PDC and PDSC into the human bronchial epithelial BEAS-2B cells was in the order PDSC > prednisolone > PDC at 37 °C. It was found that PDSC displayed 1.79-fold increase of uptake compared to prednisolone. Transport of PDSC by BEAS-2B was temperature-, time-, and Na(+)-dependent and saturable, with an apparent K(m) value of 329.74 µM, suggesting the involvement of carrier-mediated uptake. An RT-PCR study showed that organic cation/carnitine transporters OCTN1 and OCTN2 are expressed in BEAS-2B cells, but little in HEK293T cells. The order of uptake by HEK293T was prednisolone > PDC > PDSC. In addition, the inhibitory effects of organic cations such as L-carnitine, ergothioneine, TEA(+) and ipratropium on PDSC uptake in BEAS-2B cells were in the order L-carnitine > ipratropium > TEA(+) > ergothioneine, whereas their inhibitory effects on PDSC uptake in HEK293T cells were negligible. Finally, in vitro LPS-induced IL-6 production from BEAS-2B was more and longer suppressed by PDSC than prednisolone and PDC. All of these results suggested PDSC may be an attractive candidate for asthma treatment.

Pharmacokinetics of SN2310, an injectable emulsion that incorporates a new derivative of SN-38 in patients with advanced solid tumors.

SN2310 is an injectable emulsion composed of vitamin E, a succinate derivative, as well as 7-ethyl-10-hydroxycamptothecin (SN-38), the active metabolite of irinotecan. Single intravenous doses of 15, 20, 25, and 30 mg/m(2) of SN2310 emulsion were administered in a total of 26 patients with advanced solid malignancies. Serial blood samples were collected and concentrations of SN2310, SN-38, and SN-38 glucuronide were assayed. Mean systemic clearance of SN2310 ranged between 1.91 and 2.02 L/h/m(2) . Peak concentrations of SN-38 were observed at the end of infusion, suggesting a fast metabolic conversion of SN2310 to its active form, SN-38. Mean t1/2 values of SN-38 across the 20-30 mg/m(2) dose levels (131-199 h) were 33-55-fold longer than those observed for SN2310. The systemic exposure of SN-38 increased in a proportional manner over the dose range studied. SN2310 emulsion displayed an improved safety profile as compared with irinotecan. The most significant safety risk was neutropenia. Considering the rapid formation of SN-38, the proportional increase in exposure levels, and its longer elimination half-life, less frequent dosing of SN2310 emulsion may be considered for the treatment of patients with advanced solid malignancies.

Liquid chromatography tandem mass spectrometry method for the quantification of sarpogrelate, a selective 5-HT(2A) receptor antagonist, in plasma: application to a pre-clinical pharmacokinetic study.

A simple LC-MS/MS method was developed and validated for the estimation of sarpogrelate in 50 µL of rat plasma. The analyte and internal standard (IS) were extracted from rat plasma by acetonitrile precipitation and they were separated on a reversed-phase C8 column with gradient program. The MS acquisition was performed with multiple reaction monitoring mode using m/z 430.2 to m/z 135.0 for analyte and m/z 448.2 to m/z 285.3 for IS. The calibration curves were linear over the range of 1-1000 ng/mL with the correlation coefficient greater than 0.999. With dilution integrity up to 20-fold, the upper limit of quantification was extendable up to 15,000 ng/mL. The method was successfully applied to the analysis of rat plasma samples after single dose oral administration of sarpogrelate at 5 mg/kg to rats for the determination of its pharmacokinetics. Following oral administration the maximum mean concentration in plasma (C(max), 11514 ng/mL) was achieved at 0.25 h (T(max)) and the area under curve (AUC0-24) was 11051 ± 3315 ng h/mL. The half-life (t(¹/2)) and clearance (Cl) were 2.9 ± 1.1 h and 490 ± 171 mL/h/kg, respectively. We believe that development of a method in rodent plasma would facilitate the ease of adaptability of sarpogrelate in human plasma.

Pulmonary transit of agitated contrast is associated with enhanced pulmonary vascular reserve and right ventricular function during exercise.

Pulmonary transit of agitated contrast (PTAC) occurs to variable extents during exercise. We tested the hypothesis that the onset of PTAC signifies flow through larger-caliber vessels, resulting in improved pulmonary vascular reserve during exercise. Forty athletes and fifteen nonathletes performed maximal exercise with continuous echocardiographic Doppler measures [cardiac output (CO), pulmonary artery systolic pressure (PASP), and myocardial velocities] and invasive blood pressure (BP). Arterial gases and B-type natriuretic peptide (BNP) were measured at baseline and peak exercise. Pulmonary vascular resistance (PVR) was determined as the regression of PASP/CO and was compared according to athletic and PTAC status. At peak exercise, athletes had greater CO (16.0 ± 2.9 vs. 12.4 ± 3.2 l/min, P < 0.001) and higher PASP (60.8 ± 12.6 vs. 47.0 ± 6.5 mmHg, P < 0.001), but PVR was similar to nonathletes (P = 0.71). High PTAC (defined by contrast filling of the left ventricle) occurred in a similar proportion of athletes and nonathletes (18/40 vs. 10/15, P = 0.35) and was associated with higher peak-exercise CO (16.1 ± 3.4 vs. 13.9 ± 2.9 l/min, P = 0.010), lower PASP (52.3 ± 9.8 vs. 62.6 ± 13.7 mmHg, P = 0.003), and 37% lower PVR (P < 0.0001) relative to low PTAC. Right ventricular (RV) myocardial velocities increased more and BNP increased less in high vs. low PTAC subjects. On multivariate analysis, maximal oxygen consumption (VO(2max)) (P = 0.009) and maximal exercise output (P = 0.049) were greater in high PTAC subjects. An exercise-induced decrease in arterial oxygen saturation (98.0 ± 0.4 vs. 96.7 ± 1.4%, P < 0.0001) was not influenced by PTAC status (P = 0.96). Increased PTAC during exercise is a marker of pulmonary vascular reserve reflected by greater flow, reduced PVR, and enhanced RV function.

Determination of dehydroandrographolide succinate in human plasma by liquid chromatography tandem mass spectrometry (LC-MS/MS): Method development, validation and clinical pharmacokinetic study.

A LC-MS/MS method was developed and validated for the determination of dehydroandrographolide succinate (DAS), a traditional Chinese medicine derivative used for the treatment of pneumonia, upper respiratory tract infection, and chronic bronchitis. Following protein precipitation, DAS was detected by ion transition at m/z 531.2/99.0 in multiple reaction monitoring mode with negative electrospray ionization-tandem mass spectrometry. The limit of detection was 0.5ng/mL, and the lower limit of quantification was 10ng/mL in human plasma. Good linearity was maintained over the range of 10-5000ng/mL, and the correlation coefficient was better than 0.99. The accuracy ranged from 95.3% to 113%, RSD from 0.928% to 6.47%, for the within- and between-run analysis at all QC levels. The recovery ranged from 85.5% to 93.4% and the matrix effect from 107% to 119%. No significant carryover and good stability were found during method validation. The developed method was successfully applied to the determination of DAS in human plasma in a pharmacokinetic study following intravenous infusion of potassium sodium DAS to nine healthy volunteers.

Validated LC-MS/MS method for the determination of sarpogrelate in human plasma: application to a pharmacokinetic and bioequivalence study in Chinese volunteers.

A rapid and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was established for the determination of sarpogrelate in human plasma. One-step protein precipitation with acetonitrile was used to extract the analytes from the plasma. Sarpogrelate and tramadol (internal standard, I.S.) were separated on a Venusil MP-C(18) column within 1.7 min, using acetonitrile:ammonium acetate (10 mM, pH 6.8) (55:45, v/v) as mobile phase at a flow rate of 1.2 mL/min with an approximately 1:1 split entering the mass spectrometer. Detection was performed on electrospray positive ionization mass spectrometry by multiple reaction monitoring of the transitions of sarpogrelate at m/z 430.3-->135.3 and of I.S. at m/z 264.1-->58.0. The assay was validated over the concentration range of 1-1000 ng/mL with a lower limit of quantitation (LLOQ) of 1 ng/mL using 50 microL of plasma. The intra- and inter-day precision (relative standard deviation, R.S.D.) were

icoshift: A versatile tool for the rapid alignment of 1D NMR spectra.

The increasing scientific and industrial interest towards metabonomics takes advantage from the high qualitative and quantitative information level of nuclear magnetic resonance (NMR) spectroscopy. However, several chemical and physical factors can affect the absolute and the relative position of an NMR signal and it is not always possible or desirable to eliminate these effects a priori. To remove misalignment of NMR signals a posteriori, several algorithms have been proposed in the literature. The icoshift program presented here is an open source and highly efficient program designed for solving signal alignment problems in metabonomic NMR data analysis. The icoshift algorithm is based on correlation shifting of spectral intervals and employs an FFT engine that aligns all spectra simultaneously. The algorithm is demonstrated to be faster than similar methods found in the literature making full-resolution alignment of large datasets feasible and thus avoiding down-sampling steps such as binning. The algorithm uses missing values as a filling alternative in order to avoid spectral artifacts at the segment boundaries. The algorithm is made open source and the Matlab code including documentation can be downloaded from www.models.life.ku.dk.