Postmortem Diffusion of Aconitum Alkaloids and Their Metabolites in Rabbits.

OBJECTIVES: To explore the postmortem diffusion rule of Aconitum alkaloids and their metabolites in poisoned rabbits, and to provide a reference for identifying the antemortem poisoning or postmortem poisoning of Aconitum alkaloids. METHODS: Twenty-four rabbits were sacrificed by tracheal clamps. After 1 hour, the rabbits were administered with aconitine LD50 in decocting aconite root powder by intragastric administration. Then, they were placed supine and stored at 25 ℃. The biological samples from 3 randomly selected rabbits were collected including heart blood, peripheral blood, urine, heart, liver, spleen, lung and kidney tissues at 0 h, 4 h, 8 h, 12 h, 24 h, 48 h, 72 h and 96 h after intragastric administration, respectively. Aconitum alkaloids and their metabolites in the biological samples were analyzed by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). RESULTS: At 4 h after intragastric administration, Aconitum alkaloids and their metabolites could be detected in heart blood, peripheral blood and major organs, and the contents of them changed dynamically with the preservation time. The contents of Aconitum alkaloids and their metabolites were higher in the spleen, liver and lung, especially in the spleen which was closer to the stomach. The average mass fraction of benzoylmesaconine metabolized in rabbit spleen was the highest at 48 h after intragastric administration. In contrast, the contents of Aconitum alkaloids and their metabolites in kidney were all lower. Aconitum alkaloids and their metabolites were not detected in urine. CONCLUSIONS: Aconitum alkaloids and their metabolites have postmortem diffusion in poisoned rabbits, diffusing from high-content organs (stomach) to other major organs and tissues as well as the heart blood. The main mechanism is the dispersion along the concentration gradient, while urine is not affected by postmortem diffusion, which can be used as the basis for the identification of antemortem and postmortem Aconitum alkaloids poisoning.

Detection of Carbamazepine and Its Metabolites in Blood Samples by LC-MS/MS.

OBJECTIVES: To establish a method for the detection of carbamazepine and its metabolites 10,11-dihydro-10,11-epoxycarbamazepine and 10,11-dihydro-10-hydroxycarbamazepine in blood samples by liquid chromatography-tandem mass spectrometry (LC-MS/MS). METHODS: The blood samples were treated with 1-butyl-3-methylimidazolium hexafluorophosphate as an extraction solvent. The samples were extracted by ultrasound-assisted extraction and separated by ZORBAX Eclipse Plus C18, 95Å column. The mobile phase A aqueous solution containing 0.1% formic acid and 10 mmol/L ammonium acetate, and mobile phase B mixed organic solvent containing acetonitrile/methanol (Vacetonitrile∶Vmethanol=2∶3) were used for gradient elution at the flow rate of 1.00 mL/min. An electrospray ion source in positive mode was used for detection in the multiple reaction monitoring. RESULTS: The linearities of carbamazepine and its metabolites 10,11-dihydro-10,11-epoxycarbamazepine and 10,11-dihydro-10-hydroxycarbamazepine in blood samples were good within the corresponding range, with correlation coefficients (r) greater than 0.995 6. The limits of detection were 3.00, 0.40 and 1.30 ng/mL, respectively. The limit of quantitation were 8.00, 1.00 and 5.00 ng/mL, respectively. The extraction recoveries ranged from 76.00% to 106.44%. The relative standard deviations of the intra-day and inter-day precisions were less than 16%. Carbamazepine and its main metabolite 10,11-dihydro-10,11-epoxycarbamazepine were detected in blood samples of death cases with a mass concentration of 2.71 µg/mL and 252.14 ng/mL, respectively. CONCLUSIONS: This method has high sensitivity and good selectivity, which is suitable for the detection of carbamazepine and its metabolites in blood samples, and can be used for carbamazepine-related forensic identifications.

[Method for estimating relative chlorophyll content in wheat leaves based on chlorophyll fluorescence parameters]. / åŸºäºŽå¶ç»¿ç´ è§å ‰å‚æ•°çš„å°éº¦å¶ç‰‡å¶ç»¿ç´ ç›¸å¯¹å«é‡ä¼°ç®—æ–¹æ³•.

Chlorophyll content is a physiological index widely used in the research of botany and agriculture. It is closely associated with leaf photosynthetic function. The current methods cannot simultaneously determine chlorophyll content and photosynthetic function and analyze their correlation. To solve this problem, we measured the SPAD value and chlorophyll fluorescence induction kinetic curve with 35 wheat varieties. We established a linear regression model using the fluorescence values of the fast chlorophyll fluorescence kinetic curve at different times, 33 common fluorescence parameters, and the correlation between the parameters and the SPAD values. We further verified the model using laboratory and field data. Our results showed that the linear model based on chlorophyll fluorescence parameter RC/CSm could reliably predict the SPAD value of the leaves, which could be used to estimate the relative content of chlorophyll in wheat leaves under non-severe stress. The linear model enriched the method of nondestructive measurement of chlorophyll relative content in wheat, simplified the experimental flow, and achieved the simultaneous determination and analysis of wheat photosynthesis function and chlorophyll content.

[Evaluation of the Cutoff of Anti-HCV Antibody Enzyme-Linked Immunosorbent Assay in 7 Blood Station Laboratories].

OBJECTIVE: To evaluate the necessity and suitability of the anti-HCV ELISA teot gray zone setted up by 7 blood station laboratories. METHODS: 7 blood station laboratories were coded as 1, 2, 3, 4, 5, 6 and 7 respectively; 8 kinds of ELISA reagents were coded as A, B, C, D, E, F, G and H respectively. 1 or 2 of 8 ELISA reagents produced by different manufactories were used to detect the anti-HCV in specimens of same group by 7 blood station laboratories; the Westen blot was used to detect the specimens with difference of detected results so as to difine the serological status of specimens. The true positive rate of specimens detected by laboratories and gray zone-comfirined positive rate of specimens were accounted so as to analyze the necessity of setting up the gray zone for anti-HCV ELISA test of 7 blood station laboratories; the optimal cut-off value for anti-HCV ELISA test was determined in 7 blood station laborafories by ROC curve and the changes of sensitivity and specificity of 3 different cut-off value(laboratory work cut-off value, manifactory-recommended cun-off value and optimal cut-off value) were compared so as to analyze the suitability of gray zone for anti-HCV ELISA test in 7 blood station laboratories. RESULTS: The true positive rate detected by 7 blood station laboratories, out of which coded 1 laboratory used 2 kinds of coded A, B reagents was 95.40%(1A), 99.23% (1B), 94.25% (2C), 96.17% (3D), 98.08% (4E), 96.93% (5F), 97.32%(6G) and 93.10%(7H). Except for 2C(94.25%) and 7H(93.10%), the true positive rate detected by laboratoies which not sutted up gray zone, the gray zone-con-firmed positive rate in 6 blood station laboratories setted up gray zone: was 0.00%, 0.00%, 21.43%, 0.00%, 0.00%, 0.00% and 38.89%. The comparison of 3 different cut-off valuces by ROC curve showed that the anti-HCV cut-off values in 5 laboratories(1B, 2C, 4E, 5F and 6G) were as follows: optimal cut-off value＞manufactory recommeded cut-off value＞laboratory work cut-off value, thus use of manufactory-recommeded cut-off value abreadly has reached the high sensitivity requinements for laboratory screening; however, the optimal cut-off value in laboratories 1A, 3B and 7H, thas the appropriate gray zone should be used. In 6 laboratories setting up gray zone, the gensitivity in 3D, 7H laboratories only a little improved (1.60% and 2.70% raspectively) in Eamparison between laboratory work cut-off value and manufactorg-recommeded cut-off value; moreover, the sensitivity in other laboratories not is changed, but the specificity decreased (0.20%-0.50%). CONCLUSION: In addition to setting up the appropriate gray zone in laboratories 1A, 3D and 5H, the gray zone in other laboratories may be cancelled. Even in the same laboratory, the setting up the gray zone also should be scientifically assessed, the same scale cannot be blindly used, thus appropniate strategies should be established.

Sinusoidal Signal Assisted Multivariate Empirical Mode Decomposition for Brain-Computer Interfaces.

A brain-computer interface (BCI) is a communication approach that permits cerebral activity to control computers or external devices. Brain electrical activity recorded with electroencephalography (EEG) is most commonly used for BCI. Noise-assisted multivariate empirical mode decomposition (NA-MEMD) is a data-driven time-frequency analysis method that can be applied to nonlinear and nonstationary EEG signals for BCI data processing. However, because white Gaussian noise occupies a broad range of frequencies, some redundant components are introduced. To solve this leakage problem, in this study, we propose using a sinusoidal assisted signal that occupies the same frequency ranges as the original signals to improve MEMD performance. To verify the effectiveness of the proposed sinusoidal signal assisted MEMD (SA-MEMD) method, we compared the decomposition performances of MEMD, NA-MEMD, and the proposed SA-MEMD using synthetic signals and a real-world BCI dataset. The spectral decomposition results indicate that the proposed SA-MEMD can avoid the generation of redundant components and over decomposition, thus, substantially reduce the mode mixing and misalignment that occurs in MEMD and NA-MEMD. Moreover, using SA-MEMD as a signal preprocessing method instead of MEMD or NA-MEMD can significantly improve BCI classification accuracy and reduce calculation time, which indicates that SA-MEMD is a powerful spectral decomposition method for BCI.

Role of rat autologous skin fibroblasts and mechanism underlying the repair of depressed scars.

The aim of the present study was to provide reliable experimental evidence for the application of autologous skin fibroblasts (asFbs) in the repair of depressed scars. In the experiments, depressed trauma was induced in male Wistar rats, and fibroblasts were separated from the removed skin tissues to culture in medium. In vitro cultured asFbs were injected into the depressed scar sites of rats, and the repair function of asFbs in the depressed scars was then examined at the cellular and whole-animal levels. The expression levels of type I and type III collagen in the dermal layer of the skin injected with asFb cells were significantly higher, as compared with those of the control, and type I collagen expression was significantly higher compared with Type III. Re-injection of asFbs into the dermal layer of depressed scars can markedly improve their repair. These results may prove useful for skin repair in clinical settings.

[Biodegradation Characteristics and Kinetics of p-nitrophenol by Strain Arthrobacter sp. CN2].

To investigate the application potential of the p-nitrophenol-degrading bacterium Arthrobacter sp. CN2 in practice, the effects of pH, salinity and additional carbon source were determined, and the degradation kinetics of p-nitrophenol was analyzed. Strain CN2 could degrade p-nitrophenol efficiently in a wide range of pH (7.0-8.0) and elevated salinity (0-60 g · L(-1)). Investigation of additional glucose found that 0.5% of glucose could significantly increase the degrading speed and the time to reach 90% of degradation rate was shortened by 16 hours. These results indicated that strain CN2 could degrade p-nitrophenol efficiently under different conditions and had a great potential for application in practice.

Genome Sequence of Organophosphorus Pesticide-Degrading Bacterium Pseudomonas stutzeri Strain YC-YH1.

Pseudomonas stutzeri strain YC-YH1, isolated from pesticide-polluted soil, efficiently degrades organophosphorus pesticides (OPPs) such as chlorpyrifos, parathion-methyl, triazophos, and parathion. Here, we report the genome sequence (4.83 Mb) of P. stutzeri YC-YH1 to facilitate further investigation of the OPP-degrading mechanism.