Artificial neural network classification based on high-performance liquid chromatography of urinary and serum nucleosides for the clinical diagnosis of cancer

Nucleosides in human urine and serum have frequently been studied as a possible biomedical marker for cancer, acquired immune deficiency syndrome (AIDS) and the whole-body turnover of RNAs. Fifteen normal and modified nucleosides were determined in 69 urine and 42 serum samples using high-performance liquid chromatography (HPLC). Artificial neural networks have been used as a powerful pattern recognition tool to distinguish cancer patients from healthy persons. The recognition rate for the training set reached 100%. In the validating set, 95.8 and 92.9% of people were correctly classified into cancer patients and healthy persons when urine and serum were used as the sample for measuring the nucleosides. The results show that the artificial neural network technique is better than principal component analysis for the classification of healthy persons and cancer patients based on nucleoside data. (C) 2002 Elsevier Science B.V. All rights reserved.

Separation and detection of narcotic drugs on a microchip using micellar electrokinetic chromatography and electrochemiluminescence

A new approach for fast and sensitive electrochemiluminescence (ECL) detection of narcotic drugs on a microchip after separation by micellar electrokinetic chromatography (MEKC) is presented, taking the cocaine and its hydrolysate ecgonine as the test analytes. The mixture of hydrophilic BMIMBF4 ionic liquid (IL) and sodium dodecyl sulfate (SDS) was used directly as the buffer of MEKC with less noisy baselines, lower electrophoretic current and satisfactory separation performance.

Studies on the stability of diester-diterpenoid alkaloids from the genus Aconitum L. by high performance liquid chromatography combined with electrospray ionisation tandem mass spectrometry (HPLC/ESI/MSn)

The stability of diester-diterpenoid alkaloids (DDA) from plants of the genus Aconitum L. has been studied in different solvents and pH buffers. The HPLC/ESIMS method for analysing the concentration of DDA was established and DDA's decomposition products were elucidated by HPLC/ESI-MS/MSn. In different solvents, e.g. dichloromethane, ether, methanol and distilled water, the decomposition pathways of DDA are quite different and their difference in stabilities depends on the difference of their structures, in which substituents at the N atom and substituents at C-3 are different. The pyrolytic products of DDA, such as deacetoxy aconitine-type alkaloids, have been observed in the above solvents, whereas 8-methoxy-14-benzoyl aconitine-type alkaloids have been obtained only in methanol.

Studies on the aconitine-type alkaloids in the roots of Aconitum Carmichaeli Debx. by HPLC/ESIMS/MSn

Studies of aconitine-type alkaloids in the Chinese herb Aconitum Carmichaeli were performed by HPLC/ESIMS/MSn and FTICR/ESIMS in positive ion mode. The characteristic fragmentation pathways in the MSn spectra were summarized based on previously published research literature and further study. According to the fragmentation pathways of mass spectrometry, results from the analysis of standard compounds and reports from literature, 111 compounds were identified or deduced in a total of 117 found compounds in A. Carmichaeli. In the 11 monoester-diterpenoid alkaloids (MDA), 10 diesterditerpenoid alkaloids (DDA) and 81 lipo-alkaloids, the novel alkaloids including 1 MDA, 2 DDA and 48 lipo-alkaloids were detected.

Simple and rapid voltammetric determination of morphine at electrochemically pretreated glassy carbon electrodes

A simple and rapid method for morphine detection has been described based on electrochemical pretreatment of glassy carbon electrode (GCE) which was treated by anodic oxidation at 1.75 V, following potential cycling in the potential range from 0 V to 1.0 V vs. Ag vertical bar AgCl reference electrode. The sensitivity for morphine detection was improved greatly and the detection limit was 0.2 mu M. The reproducibility of the voltammetric measurements was usually less than 3% RSD for six replicate measurements. Moreover, this method could readily discriminate morphine from codeine. And an electrochemical detection of morphine in spiked urine sample was succeeded with satisfactory results.

Biochemical effects of gadolinium chloride in rats liver and kidney studied by H-1 NMR metabolomics

The biochemical effects of gadolinium chloride were studied using high-resolution H-1 nuclear magnetic resonance (NMR) spectroscopy to investigate the biochemical composition of tissue (liver and kidney) aqueous extracts obtained from control and gadolinium chloride (GdCl3) (10 and 50 mg/kg body weight, intraperitoneal injection. i.p.) treated rats. Tissue samples were collected at 48, 96 and 168 h p.d. after exposure to GdCl3, and extracted using methanol/chloroform solvent system. H-1 NMR spectra of tissue extracts were analyzed by pattern recognition using principal components analysis. The liver damages caused by GdCl3 were characterized by increased succinate and decreased glycogen level and elevated lactate, alanine and betaine concentration in liver. Furthermore, the increase of creatine and lactate, and decrease of glutamate, alanine, phosphocholine, glycophosphocholine (GPC), betaine, myo-inositol and trimethylamine N-oxide (TMAO) levels in kidney illustrated kidney disturbance induced by GdCl3.

Determination of atenolol and metoprolol by capillary electrophoresis with Tris(2,2 '-bipyridyl)ruthenium(II) electrochemiluminescence detection

Capillary electrophoresis (CE) coupling with a tris(2,2'-bipyridyl)ruthenium(II) (Ru(bpy)(3)(2+)) electrochemiluminescence (ECL) detection technique was developed for the analysis of two 8-blockers, atenolol (AT) and metoprolol (ME). The parameters that influence the separation and detection, including the buffer pH and concentration, the separation voltage, the detection potential and Ru(bpy)(3)(2+) concentration, were optimized in detail. The calibration curve was linear over a concentration range of two or three orders of magnitude for the two beta-blockers. The detection limits for AT and ME were 0.075 and 0.005 mu M (S/N = 3). The relative standard deviations (n = 8) of the ECL intensity and the migration time were 2.65 and 0.22% for AT, 2.82 and 0.34% for ME, respectively. The proposed method was applied to determine AT and ME in spiked urine samples; satisfactory results were obtained.

Metabolic profiling of serum from gadolinium chloride-treated rats by H-1 NMR spectroscopy

Metabolic profiling of serum from gadolinium chloride (GdCl3, 10 and 50 mg/kg body weight, intraperitoneal [i.p.])-treated rats was investigated by the NMR spectroscopic-based metabonomic strategy. Serum samples were collected at 48, 96, and 168 h postdose (p.d.) after exposure to GdCl3. H-1 NMR spectra of serum were analyzed by pattern recognition using principal components analysis. The studies showed that there was a dose-related biochemical effect of GdCl3 treatment on the levels of a range of low-molecular weight compounds in serum. The liver damage induced by GdCl3 was characterized by the elevation of lactate, pyruvate, and creatine as well as the decrease of branched-chain amino acids (valine and isoleucine), alanine, glucose, and trimethylamine-N-oxide concentration in serum samples. The biochemical effects of GdCl3 in rats could be consulted when evaluating the biochemical profile of gadolinium-containing compounds that are being developed for nuclear magnetic resonance imaging.

Mn(II)-monosubstituted polyoxometalates as candidates for contrast agents in magnetic resonance imaging

Two mono-substituted manganese polyoxometalates, K6MnSiW11O39 (MnSiW11) and K8MnP2W17O61 (MnP2W17), have been evaluated by in vivo and in vitro experiments as the candidates of potential tissue-specific contrast agents for magnetic resonance imaging (MRI). T-1-relaxivities of 12.1 mM(-1) s(-1) for MnSiW11 and 4.7 mM(-1) s(-1) for MnP2W17 (400 MHz, 25 degrees C) were higher than or similar to that of the commercial MRI contrast agent (GdDTPA). Their relaxivities in BSA and hTf solutions were also reported. After administration of MnSiW11 and MnP2W17 to Wistar rats, MR imaging showed longer and remarkable enhancement in rat liver and favorable renal excretion capability. The signal intensity increased by 74.0 +/- 4.9% for the liver during the whole imaging period (90 min) and by 67.2 +/- 5.3% for kidney within 20-70 min after injection at 40 +/- 3 mu mol kg(-1) dose for MnSiW11. MnP2W17 induced 71.5 +/- 15.1%. enhancement for the liver in 10-45 min range and 73.1 +/- 3.2% enhancement for kidney within 5-40 min after injection at 39 +/- 3 mu mol kg(-1) dose. In vitro and in vivo study showed MnSiW11 and MnP2W17 being favorable candidates as the tissue-specific contrast agents for MRI.

The gadolinium complexes with polyoxometalates as potential MRI contrast agents

The two gadolinium (Gd) polyoxometalates, K-15[Gd(BW11O39)(2)] [Gd(BW11)(2)] and K-17[Gd(CuW11O39)(2)] [Gd(CuW11)(2)] have been evaluated by in vivo and in vitro experiments as the candidates of potential tissue-specific magnetic resonance imaging (MRI) contrast agents. T-1 relaxivities of 17.12 mM(-1) . s(-1) for Gd(BW11)(2) and 19.95 mM(-1) . s(-1) for Gd(CuW11)(2) (400MHz, 25 degrees C) were much higher than that of the commercial MRI contrast agent (GdDTPA). Their relaxivities in bovine serum albumin and human serum transferrin solutions were also reported. After administration of Gd(BW11)(2) and Gd(CuW11)(2) to Wistar rats, MRI showed longer and remarkable enhancement in rat liver and favorable renal excretion capability. The signal intensity increased by 37.63 +/- 3.45% for the liver during the whole imaging period (100 min) and by 61.47 +/- 10.03% for kidney within 5-40 min after injection at 40 +/- 1-mu mol . kg(-1) dose for Gd(CuW11)(2), and Gd(BW11)(2) induced 50.44 +/- 3.51% enhancement in the liver in 5-50-min range and 61.47 +/- 10.03% enhancement for kidney within 5-40 min after injection at 39 +/- 4 mu mol . kg(-1) dose. In vitro and in vivo study showed that Gd(BW11)(2) and Gd(CuW11)(2) are favorable candidates as tissue-specific contrast agents for MRI.

NMR and pattern recognition studies on the acute biochemical effects of Lu(NO3)(3)

Pattern recognition methods were applied to the analysis of 600 MHz H-1 NMR spectra of urine from rats dosed with compounds that induced organ-specific damage in the liver and kidney. Male Wistar rats were separated into groups (n=4) and each was treated with one of following compounds: HgCl2, CCl4, Lu(NO3)(3) and Changle (a kind of rare earth complex mixed with La, Ce, Pr and Nd). Urine samples from the rats dosed with HgCl2, CCl4 and Lu(NO3)(3) were collected over a 24 h time course and the samples from the rats administrated with Changle were gained after 3 months. These samples were measured by 600 MHz NMR spectroscopy. Each spectrum was data-processed to provide 223 intensity-related descriptors of spectra. Urine spectral data corresponding to the time intervals, 0-8 h (HgCl2 and CCl4), 4-8 (Lu(NO3)(3)) h and 90 d (Changle) were analyzed using principal component analysis (PCA). Successful classification of the toxicity and biochemical effects of Lu(NO3)(3) was achieved.

Application of ceramic carbon materials for solid-phase extraction of organic compounds

Ceramic carbon materials were developed as new sorbents for solid-phase extraction of organic compounds using chlorpromazine as a representative. The macroporosity and heterogeneity of ceramic carbon materials allow extracting a large amount of chlorpromazine over a short time. Thus, the highly sensitive and selective determination of chlorpromazine in urine sample was achieved by differential pulse voltammograms after only 1-min extraction. The total analysis time was less than 3 min. In comparison with other electrochemical and electrochemi-luminescent methods following 1-min extraction, the proposed method improved sensitivity by about 2 and 1 order of magnitude, respectively. The fast extraction, diversity, and conductivity of ceramic carbon materials make them promising sorbents for various solid-phase extractions, such as solid-phase microextraction, thin-film microextraction, and electrochemically controlled solidphase extraction. The preliminary applications of ceramic carbon materials in chromatography were also studied.

Electrochemiluminescent detection based on solid-phase extraction at tris(2,2 '-bipyridyl)ruthenium(II)-modified ceramic carbon electrode

A sensitive electrochemiluminescent detection scheme by solid-phase extraction at Ru(bpy)(3)(2+)-modified ceramic carbon electrodes (CCEs) was developed. The as-prepared Ru(bpy)(3)(2+)-modified CCEs show much better long-term stability than other Nafion-based Ru(bpy)(3)(2+)-modified electrodes and enjoy the inherent advantages of CCEs. The log-log calibration plot for dioxopromethazine is linear from 1.0 x 10(-9) to 1.0 x 10(-4) mol L-1 using the new detection scheme. The detection limit is 6.6 x 10(-10) mol L-1 at a signal-to-noise ratio of 3. The new scheme improves the sensitivity by similar to 3 orders of magnitude, which is the most sensitive Ru(bpy)(3)(2+) ECL method. The scheme allows the detection of dioxopromethazine in a urine sample within 3 min. Since Ru(bpy)(3)(2+) ECL is a powerful technique for determination of numerous amine-containing substances, the new detection scheme holds great promise in measurement of free concentrations, investigation of protein-drug interactions and DNA-drug interactions, pharmaceutical analysis, and so on.

The use of CE-electrochemiluminescence with ionic liquid for the determination of bioactive constituents in Chinese traditional medicine

CE/tris(2,2-bipyridyl) ruthenium(ll) (Ru(bpy)(3)(2+)) electrochemiluminescence (ECL), CEECL, with an ionic liquid (IL) detection system was established for the determination of bioactive constituents in Chinese traditional medicine opium poppy which contain large amounts of coexistent substances. A minimal sample pretreatment which involves a one-step extraction approach avoids both sample loss and environmental pollution. As the nearby hydroxyl groups in some alkaloid such as morphine may react with borate to form complexes and IL, as a high-conductivity additive in running buffer, could cause an enhanced field-amplified effect of electrokinetic injection. Running buffer containing 25 mM borax-8 mM 1-ethyl-3-methylimidazolium tetrafluoroborate (EMImBF(4)) IL (pH 9.18) was used which resulted in significant changes in separation selectivity and obvious enhancement in ECL intensities for those alkaloids with similar structures. Sensitive detection could be achieved when the distance between the Pt working electrode and the outlet of separation capillary was set at 150 mu m and the stainless steel cannula was fixed approximately 1 cm away from the outlet of the capillary. Quantitative analysis of four alkaloids was achieved at a detection voltage of 1.2 V and a separation voltage of 15 kV in less than 7 min.

Facile separation and determination of Aconitine alkaloids in traditional Chinese medicines by CE with tris(2,2 '-bipyridyl) ruthenium(II)-based electrochemi-luminescence detection

A facile CE method coupled with tris(2,2'-bipyridyl) ruthenium(ll)-based electrochem iluminescence [Ru(bpy)(3)(2+)] detection was developed for simultaneous determination of Aconitum alkaloids, i.e., hypaconitine (HA), aconitine (AC), and mesaconitine (MA) in baseline separation. The optimal separation of these Aconitum alkaloids was achieved in a fused-silica capillary column (50 cm x 25 mu m id) with 30 mM phosphate solution (pH 8.40) as running buffer at 12 kV applied voltage. The three alkaloids can be determined within 10 min by a single run. The calibration curves showed a linear range from 2.0 x 10(-7) to 2.0 x 10(-5) M for HA, 3.4 x 10(-7) to 1.7 x 10(-5) M for AC, and 3.8 x 10(-7) to 1.9 x 10(-5) M for MA. The RSDs; for all analytes were below 3.01%. Good linear relationships were found with correlation coefficients for all analytes exceeding 0.993. The detection limits were 2.0 x 10(-8) M for HA, 1.7 x 10(-7) M for AC, and 1.9 x 10(-7) M for MA under optimal conditions. This method was successfully applied to determine the three alkaloids in Aconitum plants.