Separation and structural elucidation of a novel vardenafil analogue as an adulterant in a natural health care dietary supplement.

A novel vardenafil analogue was identified in dietary supplement as an adulterant in herbal formulations. The structure of this analogue was elucidated using HRMS, NMR after extraction from the pulverized powder. It was named morphardenafil as a morpholine ring has replaced the N-ethyl piperazine ring in vardenafil. A tablet of this dietary supplement contained about 50 mg of unspecified morphardenafil, which is 2.5 - 20-times the prescriptive dosage of Levetra, the commercial formulation of the vardenafil monohydrochloride salt in the market and probably places unwary consumers at risk for potentially serious adverse effects or drug-drug interaction (DDI).

Real-time visible light positioning supporting fast moving speed.

Real-time capability is a key factor which affects the practicality of an indoor positioning system significantly. While visible light positioning (VLP) is widely studied since it can provide indoor positioning functionality with LED illumination, the existing VLP systems still suffer from the high positioning latency and are not practical for mobile units with high moving speed. In this paper, a real-time VLP system with low positioning latency and high positioning accuracy is proposed. With the lightweight image processing algorithm, the proposed system can be implemented on low-cost embedded system and support real-time accurate indoor positioning for mobile units with a fast moving speed. Experimental results show that the proposed system implemented on a Raspberry Pi can achieve a positioning accuracy of 3.93 cm and support the moving speed up to 38.5 km/h.

Identification of differential metabolic characteristics between tumor and normal tissue from colorectal cancer patients by gas chromatography-mass spectrometry.

Colorectal cancer (CRC) is one of the most common human malignancies and encompasses cancers of the colon and rectum. Although the gold-standard colonoscopy screening method is effective in detecting CRC, this method is invasive and can result in severe complications for patients. The purpose of this study was to determine differences in metabolites between CRC and matched adjacent nontumor tissues from CRC patients, to identify potential biomarkers that may be informative and developed screening methods. Metabolomic analysis was performed on clinically localized CRC tissue and matched adjacent nontumor tissue from 20 CRC patients. Unsupervised analysis, supervised analysis, univariate analysis and pathway analysis were used to identify potential metabolic biomarkers of CRC. The levels of 25 metabolites in CRC tissues were significantly altered compared with the matched adjacent nontumor tissues. Four metabolites (lactic acid, alanine, phosphate and aspartic acid) demonstrated good area under the curve of receiver-operator characteristic with acceptable sensitivities and specificities, indicating their potential as important biomarkers for CRC. Alterations of amino acid metabolism and enhanced glycolysis may be major factors in the development and progression of CRC. Lactic acid, alanine, phosphate, and aspartic acid could be effective diagnostic indicators for CRC.

Extraction, derivatization, and determination of metabolome in human macrophages.

A GC/TOF-MS was applied to the determination of metabolites in human macrophages. The extraction conditions and quenching conditions were investigated and optimized. The results indicated that 0.9% w/v sodium chloride at 4°C was the most favorable condition to quench macrophage, 1 mL 50% ACN for 2 min in ice bath was the optimal condition to extract 5 × 10(6) cells. Two hundred six peaks could be detectable with peak area over 50 using this method. Among these peaks, 45 peaks with the similarity over 700 were identified using standard compounds for endogenous metabolites. Thirty-seven out of 45 metabolites could be quantified directly by this method. Twenty metabolites were selected randomly, and 15 amino acids were used for method validation. The correlation coefficients (r) ranging from 0.9902 to 0.9977 were obtained for 15 amino acids in the range of 2.35-150.20 µg/mL. The intraday and interday precisions were lower than 19.90% for the randomly selected 20 endogenous metabolites. Using this development method and multivariate statistical technique, several potential biomarkers were found from human macrophages infected by different Mycobacterium tuberculosis (M. tuberculosis) strains. The results suggest that the method could be applied to the investigation of the pathogenicity of tuberculosis.

Whole-cell matrix-assisted laser desorption/ionization time-of-flight mass spectrometry for rapid identification of bacteria cultured in liquid media.

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has been used for many years to rapidly identify whole bacteria. However, no consistent methodology exists for the rapid identification of bacteria cultured in liquid media. Thus, in this study we explored the use of MALDI-TOF MS analysis for rapid identification of cells cultured in liquid media. We determined that 2,5-dihydroxybenzoic acid (50 mg mL(-1), 50% acetonitrile, 0.1% trifluoroacetic acid) was the best matrix solution for MALDI-TOF MS for this type of study. Moreover, the tested strains were successfully differentiated by principal component analysis, and the main characteristics of the mass peaks for each species were found in mixed culture samples. In addition, we found that the minimum number of cells for detection was 1.8 × 10(3). In conclusion, our findings suggest that MS-based techniques can be developed as an auxiliary method for rapidly and accurately identifying bacteria cultured in liquid media.

Identification and quantification of salinomycin in intoxicated human plasma by liquid chromatography-electrospray tandem mass spectrometry.

Salinomycin is a polyether ionophore antibiotic that is widely used in poultry and livestock. Exposure of humans to salinomycin via inhalation or ingestion can cause severe toxicity. The aim of the present work was to develop a simple and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the rapid identification and quantification of salinomycin in human plasma. After removing protein using methanol, plasma samples were eluted from a Waters Xterra(®) MS C18 column with an isocratic mobile phase. Detection and quantification of the drug were performed with a triple-quadruple mass spectrometer by monitoring for two specific transitions in the electrospray, positive-ion, multiple-reaction monitoring mode. Assay validation showed good linearity (r(2) = 0.998). The detection and quantification limits of the method were 0.6 and 16 pg/mL, respectively. The inter- and intraday coefficients of variation for the assay were both <15%. Twelve authentic plasma samples from intoxicated patients were analyzed using this method. Salinomycin was detected in six samples, at concentrations of between 0.6 and 46.5 pg/mL. The described assay method allows the sensitive and rapid identification and quantification of salinomycin in human plasma, and thus provides a valuable tool for the specific diagnosis of salinomycin intoxication in clinical and emergency rescue practice.

Rapid detection of conotoxin SO(3) in serum using Cu-chelated magnetic beads coupled with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

A novel method based on Cu-chelated magnetic beads (Cu-Magbeads) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) was developed for the rapid detection of peptide toxins in serum. The peptides in the serum were efficiently adsorbed by the Cu-Magbeads, eluted with methanol solution, and assayed by MALDI-TOF-MS. Specific peptides were identified according to their characteristic mass-to-charge ratio values. Conotoxin SO(3), a synthesized peptide, was used as a model to evaluate the method. Conotoxin SO(3) was detected in human serum, as well as bovine and murine serum, with a detection sensitivity in the low femtomole range. The assay was performed within 40 min, without the need for a specific antibody or an expensive reagent. It shows potential for future use in clinical and emergency rescue practice because of its simplicity, high speed, and high sensitivity.

Dynamic metabonomic analysis of BALB/c mice with different outcomes after D-galactosamine/lipopolysaccharide-induced fulminant hepatic failure.

Fulminant hepatic failure (FHF) is one of the most challenging gastrointestinal emergencies encountered in clinical practice. Early identification of patients with FHF who need liver transplantation is very important. To construct a prediction model for the early diagnosis and prognosis of FHF, we studied the dynamics of metabolic intermediates and metabolic profiles with a D-galactosamine (GalN)/lipopolysaccharide (LPS)-treated BALB/c mouse model of FHF. Levels of plasma metabolites were quantified with gas chromatography/time-of-flight mass spectrometry, and data were processed with partial least squares discriminant analysis (PLS-DA). Distinct clustering differences were observed 5 and 6 hours after GalN/LPS treatment between mice that survived and those that died, but there were no differences between these groups 4 hours after treatment. Five hours after treatment, plasma levels of some metabolites differed significantly between the survival, dead, and control groups. Ketogenesis and the tricarboxylic acid cycle were inhibited in both the survival and dead groups, but in the dead group, the urea cycle was also inhibited, and glycolysis was elevated. PLS-DA indicated that principal component weighting was greatest for plasma levels of phosphate, beta-hydroxybutyrate, urea, glucose, and lactate. The Y-predicted scatter plot in the partial least squares (PLS) model assigned samples to the survival or dead groups with an a priori cutoff of 0.10 with 100% sensitivity and specificity. Similar results were observed in 11 FHF patients with different outcomes. In conclusion, the PLS model based on metabonomic analysis can be used to predict outcomes well, and plasma levels of phosphate, beta-hydroxybutyrate, urea, glucose, and lactate may constitute a set of markers for the early diagnosis and prognosis of FHF.

Metabonomic study on the toxicity of Hei-Shun-Pian, the processed lateral root of Aconitum carmichaelii Debx. (Ranunculaceae).

The purpose of this paper was to study the effects of Hei-Shun-Pian, the processed lateral root of Aconitum carmichaelii Debx. (Ranunculaceae), on the metabolic profile of rats, to discuss the mechanism of toxicology and to find out the potential biomarkers of the toxic effects. Twenty male Wistar rats were divided into four groups (n=5) and each group were administered orally with the decoction of Hei-Shun-Pian (88.1g/kg per day, 35.6g/kg per day, 17.6g/kg per day) or equal volume of drinking water respectively for 14 days. Urine of every 24-h and the plasma of the last day were collected for NMR experiments, and then analyzed by multivariate analysis methods. Decreases in urinary excretion of taurine and trimethylamine-N-oxide (TMAO) and increases in urinary levels of citrate, 2-oxoglutarate (2-OG), succinate and hippurate were observed in the high and medium dosed groups at the early stage of the dosing period. Taurine level increased at the later stage of the dosing period to the normal value, and then even to a value higher than that of the control group at the end of the experiment. No metabolic differences were observed between low dosed and control groups until the later stage of the dosing period when a slight increase in urinary taurine level was observed, suggesting a cumulative effect. These results suggest the toxic effect of Hei-Shun-Pian on rat heart in a dose dependent manner.