Biomedical subjects

Xiangmin Zhang

Publications and source records attributed to Xiangmin Zhang.

53 records · Page 3Linked to original sources

PubMed2004

Determination of acetone in human breath by gas chromatography-mass spectrometry and solid-phase microextraction with on-fiber derivatization.

Analysis of breath acetone has been used as a diagnostic tool for diabetes. Due to its nature of volatility and activity, it is very difficult to accurately measure the concentration of acetone in human breath by gas chromatography-mass spectrometry (GC-MS). To overcome this problem, we developed a new method using GC-MS and solid-phase microextraction (SPME) with on-fiber derivatization to determine acetone in human breath. Breath gas from controls and diabetic patients was collected in 3-l Tedlar bags. O-2,3,4,5,6-(Pentafluorobenzyl) hydroxylamine hydrochloride (PFBHA) in solution was firstly adsorbed on the SPME fiber of 65 microm polydimethylsiloxane-divinylbenzene (PDMS-DVB), and then the fiber was further headspace exposed in exhaled gas in the Tedlar bag at 40 degrees C for 4 min. Finally, the formed acetone oxime on the fiber was desorbed and analyzed by GC-MS. Using external standard method, acetone in the human breath was quantitatively analyzed by measurement of its oxime. The method provided a low detection limit of 0.049 ppbv for acetone in breath, relative standard deviation (R.S.D.) value of 3.4%, excellent accuracy. In addition, the method required simple sample preparation and no organic solvent. Acetone in diabetic breath was found to be higher than 1.71 ppmv, while its concentration in normal breath was lower than 0.76 ppmv. The results show that GC-MS and SPME with on-fiber derivatization is a simple, rapid and sensitive and solvent-free method for determination of low concentration acetone in breath and analysis of breath acetone can be used as supplementary tool for diagnosis of diabetes.

Acetone↗

PubMed2004

Investigation of volatile biomarkers in lung cancer blood using solid-phase microextraction and capillary gas chromatography-mass spectrometry.

In the present work, solid-phase microextraction (SPME) and gas chromatography-mass spectrometry (GC-MS) was developed for investigation of lung cancer volatile biomarkers. Headspace SPME conditions (fiber coating, extraction temperature and extraction time) and desorption conditions were optimized and applied to determination of volatiles in human blood. To find the biomarkers of lung cancer, investigation of volatile compounds in lung cancer blood and control was performed by using the present method. Concentrations of hexanal and heptanal in lung cancer blood were found to be much higher than those in control blood. The two molecules of hexanal and heptanal were regarded as biomarkers of lung cancer. By comparison of volatiles in breath and in blood, it is demonstrated that hexanal and heptanal in breath were originated from blood and screening of lung cancer by breath analysis be feasible. These results show that SPME/GC-MS is a simple, rapid and sensitive method very suitable for investigation of volatile disease markers in human blood.

Adult↗

PubMed2004

Quality assessment of Flos Chrysanthemi Indici from different growing areas in China by solid-phase microextraction-gas chromatography-mass spectrometry.

Flos Chrysanthemi Indici is a common traditional Chinese medicine (TCM). In this paper, headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME-GC-MS) was developed for quality assessment of Flos Chrysanthemi Indici from different growing areas in China. SPME parameters such as extraction fibers, extraction temperature, extraction time and sample mass were investigated to achieve identical results to those obtained by the steam distillation (SD). The selected SPME conditions were as follows: SPME fiber coated with 65-microm PDMS/DVB, extraction temperature of 60 degrees C, extraction time of 30 min and sample mass of 1.0 g. Furthermore, four active compounds (eucalyptol, camphor, borneol and bornyl acetate) presented in the TCM were applied to evaluating the quality of Flos Chrysanthemi Indici from 20 various areas. The quality assessment was successfully performed to compare the similarity value (S) between different sample vector of Flos Chrysanthemi Indici and the standard profile vector (SPV). The results showed that the proposed HS-SPME-GC-MS was an alternative technique for quality assessment of Flos Chrysanthemi Indici samples.

China↗

PubMed2004

Rapid determination of acetone in human plasma by gas chromatography-mass spectrometry and solid-phase microextraction with on-fiber derivatization.

Acetone is an important volatile disease marker. Due to its nature of activity and volatility, it is a difficult task to measure the concentration of acetone in biological samples with accuracy. In this paper, we developed a novel method for determination of trace amount acetone in human plasma by solid-phase microextraction technique with on-fiber derivatization. In this method, the poly(dimethylsiloxane)/divinylbenzene (PDMS/DVB) fiber was used and O-2,3,4,5,6-(pentafluorobenzyl) hydroxylamine hydrochloride (PFBHA) was first loaded on the fiber. Acetone in plasma sample was agitated into headspace and extracted by solid-phase microextraction (SPME) fiber and subsequently derivatized with PFBHA on the fiber. Acetone oxime was analyzed by gas chromatography-mass spectrometry (GC-MS). Quantitative analysis of acetone in plasma was carried out by using external standard method. The SPME conditions (extraction temperature and time) and the method validation were studied. The present method was tested by determination of acetone in diabetes plasma and normal plasma. Acetone concentration in diabetes plasma was found to be higher than 1.8mM, while in normal plasma was lower than 0.017 mM. The results show that the present method is a potential tool for diagnosis of diabetes.

Acetone↗

PubMed2004

Metal-ion interactions with sugars. The crystal structure and FTIR study of an SrCl2-fructose complex.

The single-crystal structure of SrCl2 x 2C6H12O6 x 3H2O was determined with Mr = 572.88, a = 16.252, b = 7.941(2), c = 10.751(3) angstroms, beta = 127.652(4) degrees, V = 1098.5(6) angstroms3, C2, Z = 2, mu = 0.71073 angstroms and R = 0.0296 for 1998 observed reflections. The fructose moiety of the complex exists as a beta-d-pyranose. The strontium atom is surrounded by eight oxygen atoms, which are arranged in symmetry-related pairs that are derived from four sugar and two water molecules. Three nonvicinal hydroxyl groups of fructose are involved in strontium binding. All the hydroxyl groups and water molecules are involved in forming an extensive hydrogen-bond network. The Sr-fructose complex is isostructural with the Ca-fructose complex, and the crystal structures and FTIR spectra of the two complexes are compared in this article. The O-H, C-O, and C-O-H vibrations are shifted, and the relative intensities changed in the complexes IR spectra, which indicate sugar metalation. By studying the metal-binding properties of fructose, it is hoped that such would aid in the understanding of the structural chemistry of metal ions interacting with saccharides, as an actual biological system, and thereby aid in the interpretation of some particular biological processes.

Crystallography, X-Ray↗

PubMed2004

Comprehensive two-dimensional chromatography and capillary electrophoresis coupled with tandem time-of-flight mass spectrometry for high-speed proteome analysis.

A comprehensive two-dimensional capillary liquid chromatography and capillary zone electrophoresis system coupled with tandem matrix assisted laser desorption/ionization-time of flight-time of flight-mass spectrometry (MALDI-TOF-TOF-MS) proteomics analyzer is presented. Protein/peptide samples were separated by capillary high-performance liquid chromatography (cHPLC). The effluents from cHPLC (the first dimension) were continuously transferred into capillary zone electrophoresis (CZE, the second dimension) through a novel valve-free hydrodynamic sampling interface. The CZE effluents were mixed with alpha-cyano-4-hydroxycinnamic acid (CHCA) matrix sheath flow via CE-MALDI interface, and then directly deposited on the MALDI target at a 3 s time-interval for further MS analysis. The high efficiency of the overall system was demonstrated by analysis of proteins in D20 (human hepatocellular carcinoma model in nude mice with high metastatic potential) liver cancer tissue. More than 300 proteins were identified, which proved the system potential for high-throughput analysis and application in proteomics.

Animals↗

PubMed2004

A simple, rapid and sensitive method for determination of aldehydes in human blood by gas chromatography/mass spectrometry and solid-phase microextraction with on-fiber derivatization.

Aldehydes are considered potential markers for enhanced oxidative stress and have been proposed as a diagnostic measure of cancer status. Do to their volatility and activity, it is very difficult to accurately measure aldehydes in human blood. In the present work, gas chromatography/mass spectrometry (GC/MS) and solid-phase microextraction (SPME) with on-fiber derivatization was developed for determination of aldehydes in human blood. O-(2,3,4,5,6-Pentafluorobenzyl)hydroxylamine hydrochloride (PFBHA) in aqueous solution was first adsorbed by a SPME fiber, and then the aldehydes in blood samples were headspace extracted by the SPME fiber and rapidly derivatized with PFBHA on the SPME fiber. Finally, the oximes formed were desorbed and detected by GC/MS in electron ionization (EI) mode. Validation of the present method was carried out, and the method was applied to quantitative analysis of the aldehydes in lung cancer blood. The results demonstrated that GC/MS and SPME with on-fiber derivatization is a simple, rapid, sensitive and solvent-free method for the determination of aldehydes in human blood.

Aldehydes↗

PubMed2004

Rapid determination of amino acids in neonatal blood samples based on derivatization with isobutyl chloroformate followed by solid-phase microextraction and gas chromatography/mass spectrometry.

The purpose of this study was to develop a simple, rapid and sensitive analytical method for determination of amino acids in neonatal blood samples. The developed method involves the employment of derivatization and a solid-phase microextraction (SPME) technique together with gas chromatography/mass spectrometry (GC/MS). Amino acids in blood samples were derivatized by a mixture of isobutyl chloroformate, methanol and pyridine, and the N(O,S)-alkoxycarbonyl alkyl esters thus formed were headspace extracted by a SPME fiber. Finally, the extracted analytes on the fiber were desorbed and detected by GC/MS in electron impact (EI) mode. L-Valine, L-leucine, L-isoleucine, L-phenylanaline and L-tyrosine in blood samples were quantitatively analyzed by measurement of the corresponding N(O,S)-alkoxycarbonyl alkyl esters using an external standard method. SPME conditions were optimized, and the method was validated. The method was applied to diagnosis of neonatal phenylkenuria (PKU) and maple syrup urine disease (MSUD) by the analyses of five amino acids in blood samples. The results showed that the proposed method is a potentially powerful tool for simultaneous screening for neonatal PKU and MSUD.

Amino Acids↗

PubMed2004

[Role of telomerase in silica induced human cell transformation].

OBJECTIVE: To explore the role of telomerase in silica induced human cell transformation in vitro. METHODS: Human telomerase catalytic subunit (hTERT) was transferred into human embryonic lung fibroblasts (HELF). 160 microg/cm2 silica dusts were added to transform HELF and hTERT transduced HELF (HELF-T+) respectively. The telomerase activity and the length of telomere were determined. The growths of the normal and transformed cells were evaluated. RESULTS: The hTERT gene was steadily transferred into HELF. Silica dusts caused the transformations of both HELF-T+ and HELF. The telomerase activities in transformed cells were higher and the telomere length of transformed cells was longer than those of HELF. CONCLUSION: The changes of telomerase activity and telomere length may play an important role in the silica induced human cells transformation.

Cell Line↗

PubMed2004

[The clinical analysis of endoscopic repair of cerebrospinal fluid rhinorrhea].

OBJECTIVE: To evaluate the points for attention, repair material and the treatment of complications in repairing cerebrospinal fluid rhinorrhea. METHOD: Fifteen cases of cerebrospinal fluid rhinorrhea were repaired. One case was pituitary tumor involving radiotherapy, two cases were spontaneous, six were traumatic, six were traumatic,six were iatrogenic. RESULT: All cases were successfully repaired by endoscopy. The successful rate were 85.6%. Some cases were relapsed in different positions and some cases needed to be repaired more than two times even five times. CONCLUSION: Endoscopic repair of cerebrospinal fluid rhinorrhea is a very good method with the virtue of convenient, high successful rate, less complication and repeatability. The method is worth spreading.

Adolescent↗

PubMed2003

Gas chromatography-mass spectrometry with solid-phase microextraction method for determination of methyl salicylate and other volatile compounds in leaves of Lycopersicon esculentum.

Methyl salicylate (MeSA) in many plants is a important signaling compound, which plays an important role in a pathogen-induced defense response. In this paper, gas chromatography-mass spectrometry (GC-MS) with headspace solid-phase microextraction (HS-SPME) was developed for determination of MeSA and other volatile compounds in leaves of a tomato plant (Lycopersicon esculentum). Tomato leaves were ground under liquid nitrogen and sampled by HS-SPME, with a 100 microm polydimethylsiloxane fiber, and finally analyzed by GC-MS. Eighteen compounds in the leaves of tomato plant infested by tobacco mosaic virus (TMV) were separated and identified, among them MeSA, which was quantitatively analyzed by the standard addition method. MeSA concentrations higher than 2.0 microg g(-1) fresh weight accumulated in leaves of TMV-infested tomato plant as the defense response to TMV. A similar concentration of MeSA in the leaves of MeSA-treated tomato plant was also found. No MeSA in leaves of control tomato plant was detected. These findings suggest that MeSA might be a signaling compound in the tomato plant response to TMV. The present method for determination of MeSA required only simple sample preparation and no organic solvent, and provided an excellent relative standard deviation of less than 5.0% and a low detection limit of 10 ng g(-1) fresh weight for MeSA. These results show that GC-MS-HS-SPME is a simple, rapid and sensitive method for determination of MeSA and other plant-signaling compounds in plant tissues.

Gas Chromatography-Mass Spectrometry↗

PubMed2003

Comprehensive two-dimensional separation system by coupling capillary reverse-phase liquid chromatography to capillary isoelectric focusing for peptide and protein mapping with laser-induced fluorescence detection.

A comprehensive two-dimensional (2-D) separation system, coupling capillary reverse-phase liquid chromatography (cRPLC) to capillary isoelectric focusing (CIEF), is described for protein and peptide mapping. cRPLC, the first dimension, provided high-resolution separations for salt-free proteins. CIEF, the second dimension with an orthogonal mechanism to cRPLC afforded excellent resolution capability for proteins with efficient protein enrichment. Since all sample fractions in cRPLC effluents could be transferred to the CIEF dimensions, the combination of the two high-efficiency separations resulted in maximal separation capabilities of each dimension. Separation effectiveness of this approach was demonstrated using complex protein/peptide samples, such as yeast cytosol and a BSA tryptic digest. A peak capacity of more than 10 000 had been achieved. A laser-induced fluorescence (LIF) detector, developed for this system, allowed for high-sensitive detection, with a fmol level of peptide detection for the BSA digest. FITC and BODIPY maleimide were used to tag the proteins, and the latter was found better both for separation and detection in our 2-D system.

Boron Compounds↗

PubMed2003

Comprehensive two-dimensional separations based on capillary high-performance liquid chromatography and microchip electrophoresis.

A novel comprehensive two-dimensional (2-D) separation system coupling capillary high-performance liquid chromatography (cHPLC) with microchip electrophoresis (chip CE) is demonstrated. Reversed-phase cHPLC was used as the first dimension, and chip CE acted as the second dimension to perform fast sample transfers and separations. A valve-free gating interface was devised simply by inserting the outlet-end of LC column into the cross-channel on a specially designed chip. A home-made confocal laser-induced fluorescence detector was used to perform on-chip high-sensitive detection. The cHPLC effluents were continuously delivered to the chip and pinched injections of the effluents every 20 seconds were employed for chip CE separation. Gradient elution of cHPLC was carried out to obtain the high-efficiency separation. Free-zone electrophoresis was performed with triethylamine buffer to achieve high-speed separation and prevent sample adsorption. Such a simple-made comprehensive system was proved to be effective. The relative standard deviations for migration time and peak height of rhodamine B in 150 sample transfers were 3.2% and 9.8%, respectively. Peptides of the fluorescein isothiocyanate (FITC)-labeled tryptic digests of bovine serum albumin were fairly resolved and detected with this comprehensive 2-D system.

Animals↗

PubMed2002

Rapid diagnosis of phenylketonuria and other aminoacidemias by quantitative analysis of amino acids in neonatal blood spots by gas chromatography-mass spectrometry.

A new method for quantifying specific amino acids in small volumes of plasma and whole blood has been developed. Volatile derivatives of amino acids are analyzed by gas chromatography-mass spectrometry. The method only takes a few minutes to perform and requires minimal sample preparation. The accurate assay of phenylalanine, tyrosine and other amino acids in dried blood spots could be used for neonatal screening for phenylketonuria and other aminoacidemias. Because of the low cost, this neonatal screening method is suited to application in developing countries such as China.

Amino Acid Metabolism, Inborn Errors↗

PubMed2002

[The utility of peak nasal inspiratory flow rate for clinical practice].

OBJECTIVE: To find out whether peak nasal inspiratory flow rate (PnIFR) of one side nose can indicate nasal patency. METHOD: PnIFR was measured using RHAT-301 wind rate meter (Qinghuatongfang Incorporated Company). One hundred subjects were recruited. We measured PnIFR of every side of nose of all subjects before and after using 3% ephedrine and registered the grade of patients' complaint of nasal obstruction. RESULT: PnIFR in normal male and in normal female are different; PnIFR in normal and in patients are different; The grade of patients' complaint of nasal obstruction is correlated with PnIFR; PnIFR in patients before and after using ephedrine are different. CONCLUSION: PnIFR of one side nose can indicate the severity of nasal obstruction; RHAT-301 flow meter is convenient to measure PnIFR for clinical practice, and PnIFR of one side nose can indicate nasal patency; PnIFR of one side nose can indicate the effect of drugs on nasal airway resistance (NAR).

Adolescent↗

PubMed2002

[Surgical management of cerebrospinal fluid rhinorrhea].

OBJECTIVE: To summarize the clinical experience in managing cerebrospinal fluid (CSF) rhinorrhea. To ascertain the best effective surgical management for CSF rhinorrhea. METHODS: A retrospective study of 83 patients with CSF rhinorrhea from March 1991 to August 2001 was conducted. Among them, 17 patients were treated with conservative therapy, 8 with transcranial repair, 2 with extranasal repair, 3 with transnasal repair under microscope and 54 with transnasal endoscopic management. The conservative time, causes, complications, leak sites, repairing materials and surgical methods were analysed. RESULTS: All patients were followed -up for 6 months to 9 years. 17 cases had no CSF rhinorrhea after conservative treatment with an average time 16 days. Endoscopic repair of CSF leaks was successful in 90% (49/54) of the cases after a first attempt. Two persistent leaks (2/4) were closed after a second attempt. The other persistent leaks were also closed, one case after third and one after fourth attempt. Ultimately 98% (53/54) of the leaks were repaired using an endoscopic approach. Only one failed after transendoscopic management, and succeeded with a second extranasal repair. The CSF rhinorrhea repaired with other surgical methods were all successful. CONCLUSION: Transnasal endoscopic management is the best method for repairing CSF rhinorrhea, other surgical methods can be chosen based on different conditions. The conservative time are 2 to 4 weeks if a CSF leak is caused by trauma or operation, 6 to 8 weeks conservative time for special cases.

Adolescent↗

PubMedDate not supplied

Comparison of solid-phase microextraction, supercritical fluid extraction, steam distillation, and solvent extraction techniques for analysis of volatile consituents in Fructus Amomi.

Four sampling techniques, solid-phase microextraction (SPME), supercritical fluid extraction (SFE), steam distillation (SD), and solvent extraction (SE), were compared for the analysis of volatile constituents from a traditional Chinese medicine (TCM) of the dried ripe fruit of Fructus Amomi (Sha Ren). A total of 38 compounds were identified by gas chromatography/mass spectrometry. Different SFE and SPME parameters (modifier content, extraction pressure, and temperature for SFE and fibers, extraction temperature, and time for SPME) were studied. The results by SFE and SPME were compared with those obtained by conventional SD and SE methods. The results showed that SFE and SPME are better sample preparation techniques than SD and SE. Due to SFE's requirement for expensive specialized instrumentation, the simplicity, low cost, and speed of SPME make it a more appropriate technique for extraction of volatile constituents in TCMs.

Amomum↗