Anti-Inflammatory Triterpenoids from the Caulophyllum robustum Maximin LPS-Stimulated RAW264.7 Cells.

Caulophyllum robustum Maxim is widely distributed in China and used as a traditional herbal medicine to induce childbirth, ease the pain of labor, rectify delayed or irregular menstruation, alleviate heavy bleeding and pain during menstruation, and treat external injuries and irregular menses. According to our detailed chemical investigation, three new triterpene derivatives (1⁻3), together with seven known compounds, were isolated from the root and rhizome of C. robustum Maxim. Their structures were elucidated by 1D- and 2D-NMR spectroscopic analysis and physio-chemical methods. They were identified as (1) 23-hydroxy-3,19-dioxo-olean-12-en-28-oic-acid; (2) 23-hydroxy-3,11-dioxo-olean-12-en-28-oic acid; and (3) 16α,23-dihydroxy-3-oxo-olean-12-en-28-oic acid. Compounds (1⁻10) inhibited the LPS-activated NO production in RAW264.7 cells. Furthermore, the anti-inflammatory characteristics of these compounds were confirmed on the basis of decreases in iNOS and NF-κB protein expression in RAW264.7 cells.

Mechanism research of Bu-Shen-Huo-Xue formula against renal fibrosis in rats with 5/6 nephrectomy via E-cadherin, α-SMA, and TGF-ß1
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OBJECTIVE: Renal fibrosis generally results in renal failure during the end stage of chronic renal diseases. There are many cell factors including E-cadherin, α-SMA, and TGF-ß1 influencing deposition of extracellular matrix and leading to renal fibrosis. As the most important and widely-used therapy for various diseases in China for thousands of years, traditional Chinese medicine (TCM) provides a novel treatment for renal fibrosis. For clinical application, we explore the effect of Bu-Shen-Huo-Xue formula (BSHX), a traditional Chinese herbal formula, on E-cadherin and α-SMA in rats with 5/6 nephrectomy. MATERIALS AND METHODS: Sprague-Dawley rats were subjected to 5/6 nephrectomy to induce chronic renal failure (CRF); they were divided into three groups including a CRF control group, a BSHX group, and a Cozaar group, and compared with a normal control group. After 8 weeks of therapy with the respective drug, E-cadherin, α-SMA, and TGF were detected by immunohistochemistry assays in renal tissues. RESULTS: As the immunohistochemistry assays indicated, BSHX could significantly enhance the expression of E-cadherin and depress the levels of α-SMA and TGF-ß1 expression in rats' renal tissues with 5/6 nephrectomy. CONCLUSION: BSHX can effectively relieve the renal fibrosis in rats with 5/6 nephrectomy via the change of cell factor levels including enhancement of the expression of E-cadherin and depression of the levels of α-SMA and TGF-ß1 expression.
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Clinical characteristics of sleep disorders in patients with Parkinson's disease.

In order to investigate the sleep quality and influencing factors in patients with Parkinson's disease (PD), 201 PD patients were enrolled and underwent extensive clinical evaluations. Subjective sleep evaluation was assessed using the Pittsburgh Sleep Quality Index (PSQI), and the Epworth Sleepiness Scale (ESS). It was found that poor sleep quality (77.11%) and excessive daytime sleepiness (32.34%) were commonly seen in PD patients and positively correlated with disease severity. Then 70 out of the 201 PD patients and 70 age- and sex-matched controls underwent a polysomnographic recording. The parameters were compared between PD group and control group and the influencing factors of sleep in PD patients were analyzed. The results showed that sleep efficiency (SE) was significantly decreased (P<0.01), and sleep latency (SL) and the arousal index (AI) were increased (P<0.05) in the PD group as compared with those in the control group. SE and total sleep time (TST) were positively correlated with the Hoehn and Yahr (H&Y) stage. There was significant difference in the extent of hypopnea and hypoxemia between the PD group and the control group (P<0.05). Our results indicate that PD patients have an overall poor sleep quality and a high prevalence of sleep disorder, which may be correlated with the disease severity. Respiratory function and oxygen supply are also affected to a certain degree in PD patients.

Clinical Characteristics of Sleep Disorders in Patients with Parkinson's Disease / 华中科技大学学报（医学）（英德文版）

In order to investigate the sleep quality and influencing factors in patients with Parkinson's disease (PD),201 PD patients were enrolled and underwent extensive clinical evaluations.Subjective sleep evaluation was assessed using the Pittsburgh Sleep Quality Index (PSQI),and the Epworth Sleepiness Scale (ESS).It was found that poor sleep quality (77.11％) and excessive daytime sleepiness (32.34％) were commonly seen in PD patients and positively correlated with disease severity.Then 70 out of the 201 PD patients and 70 age-and sex-matched controls underwent a polysomnographic recording.The parameters were compared between PD group and control group and the influencing factors of sleep in PD patients were analyzed.The results showed that sleep efficiency (SE) was significantly decreased (P＜0.01),and sleep latency (SL) and the arousal index (AI) were increased (P＜0.05) in the PD group as compared with those in the control group.SE and total sleep time (TST) were positively correlated with the Hoehn and Yahr (H&Y) stage.There was significant difference in the extent of hypopnea and hypoxemia between the PD group and the control group (P＜0.05).Our results indicate that PD patients have an overall poor sleep quality and a high prevalence of sleep disorder,which may be correlated with the disease severity.Respiratory function and oxygen supply are also affected to a certain degree in PD patients.

[Protein and mRNA expression of CTGF, CYR61, VEGF-C and VEGFR-2 in bone marrow of leukemia patients and its correlation with clinical features].

This study was aimed to investigate the mRNA and protein expression of CTGF, CYR61, VEGF-C and VEGFR-2 in bone marrow of patients with leukemia, and to analyze the role and clinical significance of these 4 factors in genesis and development of leukemia, infiltration and metastasis of leukemic cells. A total of 100 cases of newly diagnosed leukemia, 26 cases of acute leukemia in complete remission and 30 controls were enrolled in this study. The mononuclear cells of bone marrow were collected, the mRNA and protein expression levels of CTGF, CYR61, VEGF-C, VEGFR-2 in leukemia patients and controls were detected by real time PCR and Western blot, respectively. The results showed that the mRNA and protein expression levels of above mentioned 4 factors were significantly higher than those in control (P < 0.05), only CTGF mRNA expression in AL patients after complete remission showed statistical difference as compared with control (P < 0.05), but the expression of CTGF mRNA showed statistical significance in different bone marrow hyperplasia of acute leukemia (P < 0.05). The expression level of CTGF protein showed difference in different chromosome karyotypes of leukemia (P < 0.05). The expression levels of CYR61 and VEGF-C proteins showed statistical difference in different bone marrow hyperplasia of acute leukemia (P < 0.05). The expression level of CTGF, CYR61, VEGF-C mRNA and protein in CML group were higher than that in control group. The expression levels of CTGF and CYR61 protein were higher than that in control. The mRNA and protein expression levels of above-mentioned 4 factors in sex and infiltration lf leukemic cells did not show statistical significance(P < 0.05). In correlative analysis, the mRNA expressions of above mentioned 4 factors were positively correlated with bone marrow blast count(P < 0.05), the protein expression of CTGF, CYR61 and VEGF-C were positively correlated with bone marrow blast count. It is concluded that the CTGF, CYR61, VEGF-C and VEGFR-2 mRNA and protein play a role in acute leukemia. In acute leukemia (AML/ALL), the expression of above mentioned factor was high, but except VEGFR-2. Most of them were positively correlated with bone marrow blast count. Joint block of these angiogenesis-related factors is likely to play an important role in targeting treatment of leukemia.

Protective Effects of Bu-Shen-Huo-Xue Formula against 5/6 Nephrectomy-Induced Chronic Renal Failure in Rats.

Chronic renal failure (CRF) is a serious disease related to increasing incidence and prevalence as well as decline in quality of life. Bu-Shen-Huo-Xue formula (BSHX), one of traditional herbal formulations, has been clinically employed to treat CRF for decades, but the mechanisms involved have not been investigated. In the present study, we investigated the effects of BSHX on some closely related parameters in 5/6 nephrectomy CRF rats. Rats with CRF were divided into five groups, namely, one control group, one enalapril group, and three BSHX treatment groups (0.25, 0.5, and 1 g/kg·d). The rats subjected to sham operation were used as a normal control. After eight weeks of treatment, BSHX significantly decreased the levels of Scr and BUN, downregulated the mRNA expression levels of TGF-ß 1, CTGF, NF-κB, TNF-α, and OPN, upregulated the mRNA expression of PPARγ, and reduced in situ expression of fibronectin and laminins. Histological findings also showed significant amelioration of the damaged renal tissue. BSHX protects 5/6 nephrectomy rats against chronic renal failure probably via regulating the expression of TNF-α, NF-κB, TGF-ß 1, CTGF, PPARγ, OPN, fibronectin, and laminins and is useful for therapy of CRF.

αν and ß1 Integrins mediate Aß-induced neurotoxicity in hippocampal neurons via the FAK signaling pathway.

αν and ß1 integrins mediate Aß-induced neurotoxicity in primary hippocampal neurons. We treated hippocampal neurons with 2.5 µg/mL 17E6 and 5 µg/mL ab58524, which are specific αν and ß1 integrin antagonists, respectively, for 42 h prior to 10 µM Aß treatment. Next, we employed small interfering RNA (siRNA) to silence focal adhesion kinase (FAK), a downstream target gene of integrins. The siRNAs were designed with a target sequence, an MOI of 10 and the addition of 5 µg/mL polybrene. Under these conditions, the neurons were transfected and the apoptosis of different cell types was detected. Moreover, we used real-time PCR and Western blotting analyses to detect the expression of FAK and ρFAK genes in different cell types and investigated the underlying mechanism and signal pathway by which αν and ß1 integrins mediate Aß-induced neurotoxicity in hippocampal neurons. An MTT assay showed that both 17E6 and ab58524 significantly increased cell viability compared with the Aß-treated neurons (P<0.01 and P<0.05, respectively). However, this protective effect was markedly attenuated after transfection with silencing FAK (siFAK). Moreover, TUNEL immunostaining and flow cytometry indicated that both 17E6 and ab58524 significantly protected hippocampal neurons against apoptosis induced by Aß (P<0.05) compared with the Aß-treated cells. However, this protective effect was reversed with siFAK treatment. Both the gene and protein expression of FAK increased after Aß treatment. Interestingly, as the gene and protein levels of FAK decreased, the ρFAK protein expression markedly increased. Furthermore, both the gene and protein expression of FAK and ρFAK were significantly diminished. Thus, we concluded that both αν and ß1 integrins interfered with Aß-induced neurotoxicity in hippocampal neurons and that this mechanism partially contributes to the activation of the Integrin-FAK signaling pathway.

[Rapid detection of residual cyclohexanone in disposable medical devices by ultraviolet photoionization ion mobility spectrometry (UV-IMS)].

In the manufacture of disposable PVC medical devices, cyclohexanone is frequently used as an adhesive reagent, which can be released into the tube airspace or stored solution and thus may cause some adverse effects on patients in therapy. In this paper, an ultraviolet photoionization ion mobility spectrometry (UV-IMS) technique has been developed to detect cyclohexanone through monitoring the gas composition within a package of infusion sets. The concentrations of cyclohexanone were prepared by means of exponential dilution method, and the experiments show that the UV-IMS has a limit of detection at 15 ppb and its measurable linear dynamics range is over three orders of magnitude. The concentrations of cyclohexanone in three brands of infusion sets packages were determined to be 16.78, 17.59 and 46.69 ppm respectively. The UV-IMS is proposed as a tool for the quality control of medical devices to monitor illegal uses of chemical solvents like cyclohexanone.

[Expression of CYR61, CTGF, VEGF-C, VEGFR-2 mRNA in bone marrow of leukemia patients and its clinical significance].

The study was aimed to detect the levels of CYR61, CTGF, VEGF-C, VEGFR-2 mRNA in bone marrow (BM) of leukemia patients and investigate the interaction of CYR61, CTGF, VEGF-C, VEGFR-2 proteins in occurrence, development, infiltration and metastasis of leukemia and its clinical significance, to find a new tumor marker for diagnosis and treatment of leukemia with some new directions. 74 patients with leukemia were enrolled in this study, 38 out of them were males and 36 were females, aged from 6 to 77 years old with the median age of 45 years old. In the control group, 7 males and 5 females, aged from 16 to 78 years old with the median age of 46. Semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) was used to detect the levels of CYR61, CTGF, VEGF-C, VEGFR-2 mRNA. The results showed that the levels of CYR61, CTGF, VEGF-C, VEGFR-2 mRNA in BM of newly diagnosed patients with acute and chronic leukemia of each group were significantly higher as compared with the control group (p < 0.05). The levels of CYR61, CTGF mRNA in acute leukemia remission group were significantly higher than those in control group (p = 0.039, 0.025). The level of CTGF mRNA was highest in B-ALL group, and was higher than that in AML, CML, CLL, T-ALL groups (p = 0.002, 0.034, 0.002, 0.010). In AML group, mRNA expressions of CYR61 and CTGF, CYR61 and VEGF-C, CTGF and VEGFR-2 were positively correlated (r = 0.452, 0.466, 0.464; p = 0.045, 0.038, 0.039), and in CML group mRNA expression of CYR61 and VEGF-C was positively correlated (r = 0.882, p = 0.000). The expression levels of VEGF-C, VEGFR-2 mRNA in acute leukemia patients with extramedullary infiltration were higher than those in acute leukemia patients without extramedullary infiltration (p = 0.028, 0.047). VEGF-C mRNA expression and the original cell counts in AML group were positively correlated (r = 0.418, p = 0.034). It is concluded that CYR61, CTGF, VEGF-C and VEGFR-2 interact each other in the pathogenesis of leukemia, promote the development, metastasis and infiltration of leukemia; and these factors in different types of leukemia and extramedullary infiltration are different, which may become tumor markers of leukemia; and blocking VEGF-C and VEGFR-2 may block tumor growth and metastasis.

[Determination of metal by liquid electrode discharge atomic emission spectrometry with a new design].

A liquid electrode discharge atomic emission spectrometry has been developed with a new design. Plasma fluctuation from the variations in the gap between the W anode and liquid cathode was eliminated by providing a sawtooth-shaped drainage structure. The sawtooth was placed at a distance of 2 mm from the glass capillary top. When a solution is pumped through a glass capillary, the liquid drop forms and rises and on reaching the maximum size collapses while the next drop forms. This results in a continuous change in the interelectrode distance which will cause the discharge current to change, plasma flickers and is extinguished. With the new design, the surface tension of the drop was destroyed before its growing up, and the solution was flowing along the drainage groove. The discharge can last for 3 hours at least with such arrangement. The analytical response curves for lead, chromium, cadmium, zinc, vanadium, nickel, copper, silver and cobalt demonstrated good linearity. The limit of detections of lead, chromium, cadmium, zinc, vanadium nickel, copper, silver and cobalt were determined to be 0.08, 0.61, 0.48, 1.60, 10.88, 0.48, 0.084, 0.048 and 0.27 mg x L(-1) respectively.

[Detection of metal residue in aqueous solutions by electrolyte cathode atmospheric glow discharge emission spectroscopy].

Toxic metal elements in waters and wastewaters contaminate the environment and greatly threaten the health of human beings, therefore developing a rapid monitor for metal residues in aqueous solutions is urgently required. In the present work, a new homemade apparatus of electrolyte cathode atmospheric glow discharge emission spectroscopy was developed and described. It can detect and discriminate many kinds of trace mental elements by atomic emission spectrum from atmospheric pressure liquid cathode glow discharge. In order to estimate the analytical performance of the present atmospheric pressure electrolyte cathode glow discharge emission spectroscopy system, the detection limit values for Na, Li, Cu, Pb and Mn were obtained based on 3sigma of the background signal, and the current limits of detection were 0.008, 0.005, 1.1, 2.06 and 1.95 mg L(-1), respectively. It demonstrates that the atmospheric pressure electrolyte cathode glow discharge emission spectroscopy has a promising application in real time measurements of metal residues in aqueous solutions.

[Characterization of an atmospheric pressure DC microplasma jet].

In the present work, a simply designed and easy made micrometer plasma jet device operating under atmospheric pressure was characterized. The microplasma jet operates in many kinds of working gas at atmospheric pressure, such as Ar, He, N2 etc, and is powered by a direct current power source. It can generate high current density glow discharge. In order to identify various excited species generated by the direct current microplasma jet device, the optical emission spectra of the jet with argon or nitrogen as working gas were studied. Based on the optical emission spectroscopy analysis of argon microplasma jet, the electron excitation temperature was determined to be about 3 000 K by the intensity ratio of two spectral lines. It is much lower than the electron excitation temperature of atmospheric pressure plasma torch, and hints that the atmospheric pressure direct current microplasma jet is cold compared with the atmospheric pressure plasma torch. The emission spectra of the N2 second positive band system were used to determine the vibrational temperature of the atmospheric pressure direct current microplasma jet. The experimental result shows that the molecular vibrational temperature of N2 is about 2 500 K. The electron density of the microplasma jet is about 10(13) cm(-3), which can be estimated from the electrical parameters of the discharge in the microplasma jet. A simple example of application of the microplasma jet is given. General print paper surface was modified with the microplasma jet and afterwards a droplet test was carried out. It was shown that the microplasma jet is more efficient in changing the hydrophilicity of general print paper.

[Expression of cyclooxygenase-2 in bone marrow cells of leukemia patients and its association with angiogenesis].

The objective of this study was to investigate the effect of cyclooxygenase-2 (COX-2) in the angiogenesis of bone marrow in leukemia patients. 51 patients with newly diagnosed acute leukemia were taken as study objects, 18 healthy volunteers were enrolled in the control group. Bone marrow microvessel density (MVD) in bone marrow biopsy tissue section was determined with immunohistochemistry method, the vascular endothelial growth factor level in serum was detected with ELISA method and the expression of cyclooxygenase-2 in bone marrow cells was assayed by flow cytometry. The results showed that the MVD, VEGF level, positive rate of COX-2 expression in leukemia group all obviously increased as compared with the control group (p < 0.05). The correlative coefficients of MVD, VEGF level and COX-2 expression rate were 0.614, 0.423 and 0.577 respectively (p < 0.05). In conclusion, as well as solid tumors, leukemia may be also a angiogenesis-dependent malignant tumor. Coordination of COX-2 with VEGF may promote angiogenesis in bone marrow.

[Spectroscopic study of atmospheric pressure argon DC microdischarge].

Microhollow cathode discharge or microdischarge is an efficient method to generate plasma in a high pressure gas. In the present work, the emission spectra were observed in an atmospheric pressure argon direct current microdischarge apparatus, using a stainless steel capillary as the cathode, and a stainless steel mesh as the anode. It was shown that all of the seventeen argon spectral lines arose from electronically excited argon atom 4p-4s transition in the wavelength range of 690-860 nm. The dependences of emission intensity on the discharge current, gas pressure and argon flow rate were investigated. The experimental results show that the emission intensity increased with discharge current from 1 to 6 mA and argon flow rate from 100 to 700 mL x min(-1). The dependence of emission intensity on gas pressure exhibited different characteristics, i.e., spectral signal increased with the gas pressure, but reached the intensity maximum at 13.3 kPa, and decreased afterwards. The argon atom spectral lines 763.51 and 772.42 nm were chosen to measure the electron excitation temperature by the intensity ratio of two spectral lines. The electron excitation temperature was determined to be in the range of 2000 to 2800 K in the atmospheric pressure argon microdischarge. The changes in electron excitation temperature with discharge current, gas pressure and argon flow rate were explored, indicating that the electron excited temperature increased with the discharge current, but decreased when gas flow rate or argon pressure increased.

Polycyclic aromatic hydrocarbons aggravate antigen-induced nasal blockage in experimental allergic rhinitis.

It has been hypothesized that air pollution has played a role in the increase in allergy prevalence. However, it remains unclear what exact roles are played by polycyclic aromatic hydrocarbons (PAHs), which are encountered in the environment in the form of air pollution, in allergic rhinitis. Thus, we examined whether benzo(a)pyrene (BaP) and 1-nitropyrene (1-NP), representative PAHs, aggravate allergic rhinitis symptoms, using a guinea-pig model. Sensitized animals were repeatedly challenged by inhalation of Japanese cedar pollen once a week. BaP or 1-NP was daily and intranasally administered for 2 weeks (short-term treatment) or for 22 weeks from the time before the sensitization period (long-term treatment). The short-term treatment affected neither nasal blockage nor sneezing induced by antigen. In contrast, the long-term treatment aggravated the antigen-induced nasal blockage that was induced 7 weeks after the start of the treatment with BaP or 1-NP. This aggravation continued during the intranasal treatment with PAH. However, neither sneezing nor Cry j 1-specific IgE antibody production was affected even by the long-term treatment. In conclusion, the long-term treatment with BaP and 1-NP can aggravate allergic rhinitis. The mechanisms underlying this aggravation are not associated with production of Cry j 1-specific IgE.

Determination of alcohol compounds using corona discharge ion mobility spectrometry.

Ion mobility spectrometry (IMS) is a very fast, highly sensitive, and inexpensive technique, it permits efficient monitoring of volatile organic compounds like alcohols. In this article, positive ion mobility spectra for six alcohol organic compounds have been systematically studied for the first time using a high-resolution IMS apparatus equipped with a discharge ionization source. Utilizing protonated water cluster ions (H2O)n H+ as the reactant ions and clean air as the drift gas, alcohol organic compounds, ethanol, 1-propanol, 2-propanol, 1-butanol, 1-pentanol and 2-octanol, all exhibit product ion characteristic peaks in their respective ion mobility spectrometry, that is a result of proton transfer reactions between the alcohols and reaction ions (H2O)n H+. The mixture of these alcohols, including two isomers, has been detected, and the results showed that they could be distinguished effectively in the ion mobility spectrum. The reduced mobility values have been determined, which are in very well agreement with the traditional 63Ni-IMS experimental values. The exponential dilution method was used to calibrate the alcohol concentrations, and a detection limit available for the alcohols is in order of magnitude of a few ng/L.

Nasal blockage induced by oral administration of non-steroidal anti-inflammatory drugs in a guinea-pig model of allergic rhinitis.

To elucidate the mechanisms underlying nasal symptoms in patients with aspirin hypersensitivity, we evaluated the effects of orally administered non-steroidal anti-inflammatory drugs (NSAIDs) on the nasal patency of guinea pigs with cedar pollen-induced chronic allergic rhinitis. Indomethacin (10 mg/kg) administered 1 h before a pollen challenge amplified the antigen-induced nasal blockage. More interestingly, even in the absence of the pollen challenge, indomethacin induced nasal blockage at 30 min at 4 h after administration. However, indomethacin-induced nasal blockage was not provoked in non-sensitized animals. Another NSAID, diclofenac (30 mg/kg), also evoked nasal blockage, but unexpectedly, aspirin (500 mg/kg) did not affect nasal patency. Indomethacin-induced nasal blockage was unaffected by a cysteinyl leukotriene receptor (CysLT(1) receptor) antagonist, pranlukast (30 mg/kg, p.o.), or by prostaglandin E2 (10(-3) M, intranasal), suggesting that the nasal blockage may not be due to hyperproduction of cysteinyl leukotrienes or inhibition of prostaglandin E2 production. These results indicate that the indomethacin-induced nasal blockage may not be an identical phenomena to airway symptoms in aspirin hypersensitivity patients. However, because chronic nasal inflammation is indispensable for the development of nasal blockage, indomethacin-induced nasal blockage may become a clue to elucidate new mechanisms underlying hypersensitivity to NSAIDs.

[Discharge ion mobility spectrometry of ketonic organic compounds].

Ion mobility spectrometry (IMS) is a sensitive technique for fast on-line monitoring trace volatile organic compounds based upon the mobilities of gas phase ions at ambient pressure in weak electric field. In the present work, protonated water reactant ions were successfully prepared, and eight ketones were studied on a homemade high-resolution IMS apparatus using a discharge ionization source. The reduced mobility values of all ions were derived from the observed ion mobility spectra. The experimentally determined reduced mobilities for acetone, 2-butone, 1-methyl-2-pyrrolidinone acetophenone, cyclohexanone and product ions were compared with the previously reported values in the Ni-IMS, indicating that they are in good agreement. The reduced mobilities of methyl isopropyl ketone, 4-methyl-2-pentanone and cyclopentanone ions were given for the first time. The ionization process for organic compounds in the authors' discharge ion mobility spectrometer is suggested to be similar to Ni-IMS system, i.e., the proton transfer reactions produce protonated ketone ions. In addition, a linear correlation was found between the reduced mobilities of the ketone ions and their molecular masses. Qualitative measurements show that the limit of detection is in the ng x L(-1) order of magnitude in the authors' discharge ion mobility spectrometer.

[Ion mobility spectrometry for the isomeric volatile organic compounds].

Ion mobility spectrometry (IMS) is based on determining the drift velocities, which the ionized sample molecules attain in the weak electric field of a drift tube at atmospheric pressure. The drift behavior can be affected by structural differences of the analytes, so that ion mobility spectrometry has the ability to separated isomeric compounds. In the present article, an introduction to IMS is given, followed by a description of the instrument used for the experiments to differentiate isomeric compounds. Positive ion mobility spectras of three kinds of isomeric volatile organic compounds were studied in a homemade high-resolution IMS apparatus with a discharge ionization source. The study includes the differences in the structure of carbon chain, the style of function group, and the position of function group. The reduced mobility values were determined, which are in very good agreement with the previously reported theoretical values using neural network theory. The influence of the structural features of the substances and including the size and shape of the molecule has been investigated. The reduced mobility values increases in the order: alcohols < acetones < aromas, linears < branches < cycles, and para- < meta- < ortho-. The deviating ion mobility spectra of the constitutional isomers studied reflect the influence of structural features. In order to calibrate or determine the detection limits and the sensitivity of the ion mobility spectrometry, the exponential dilution flask (EDF) was used. Using this method, the detection limit of the analytes can reach the order of magnitude of ng x L(-1).