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Find video protocols related to scientific articles indexed in Pubmed.
Tissue Depletion of Quinocetone and Its Five Major Metabolites in Pigs, Broilers, and Carp Fed Quinocetone Premix.
J. Agric. Food Chem.
PUBLISHED: 10-05-2014
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A residue depletion study was performed to investigate the tissue kinetics of quinocetone (1) and its major metabolites. Quinocetone and its major metabolites were simultaneously quantitated with a high-performance liquid chromatography-ultraviolet (HPLC-UV) method. A total of 25 pigs, 30 broilers, and 50 carp were fed 100 mg/kg quinocetone for 90, 42, and 60 days, respectively. Liver, kidney, muscle, and fat (skin) tissues were collected at five different withdrawal times for analysis. Results revealed that quinocetone, 1-desoxyquinocetone (2), carbonyl-reduced 4-desoxyquinocetone (4), 3-methylquinoxaline-2-carboxylic acid (5), and carbonyl-reduced dideoxyquinocetone (6) could be depleted quickly in tissues; by contrast, dideoxyquinocetone, 3, persisted for a long time in the liver. Therefore, the liver is possibly the target tissue of quinocetone, and 3 is the residual marker; the recommended withdrawal times (WDTs) are 0 days in pigs and carp and 3 days in broilers. These results provided clear monitoring tools and technical standards to evaluate the food safety of quinocetone.
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Saliva as a sampling source for the detection of leukemic fusion transcripts.
J Transl Med
PUBLISHED: 08-09-2014
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BackgroundSaliva has long been used as a sampling source for clinical diagnosis of oral disease such as oral squamous cell carcinoma, or therapeutic drug monitoring. The aims of this study was to ascertain if saliva RNA could be stored at room temperature and to study if saliva could be a convenient source for fusion transcripts in leukemic patients.MethodsThis is a cross-sectional diagnostic study. We first developed a Saliva RNA tube for stable storage of whole saliva RNA at room temperature. Then we detected the leukemic fusions in the whole saliva from seven leukemic patients and twenty healthy volunteers, and compared with the results obtained from the bone marrow of the patients.ResultsHuman gene transcripts could be reproducibly detected in the whole saliva for at least four weeks when stored in the developed composition at room temperature. Concordant results of the fusion transcripts were obtained between the saliva and the bone marrow in the seven leukemic patients and no fusions were detected in the healthy controls.ConclusionsThe results support our hypothesis that human whole saliva could be a reliable and convenient sampling source for the detection of leukemic fusions.
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Environmental Equity Research: Review with Focus on Outdoor Air Pollution Research Methods and Analytic Tools.
Arch Environ Occup Health
PUBLISHED: 06-28-2014
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Abstract Objective: To review environmental equity research on outdoor air pollution, and specifically methods and tools used in research published in English, with the aim of recommending the best methods and analytic tools. Methods: English language publications from 2000-2012 were identified in Google Scholar, Ovid Medline and PubMed. Research methodologies and results were reviewed, and potential deficiencies and knowledge gaps identified. Results: Exposure to outdoor air pollution differs by social factors, but findings are inconsistent in Canada. In terms of study designs, most were small and ecological, and therefore prone to the ecological fallacy. Newer tools such as geographic information systems, modeling and biomarkers offer improved precision in exposure measurement. Conclusion: Higher quality research using large, individual-based samples and more precise analytic tools are needed to provide better evidence for policy-making to reduce environmental inequities.
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Incorporating MRI structural information into bioluminescence tomography: system, heterogeneous reconstruction and in vivo quantification.
Biomed Opt Express
PUBLISHED: 06-01-2014
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Combining two or more imaging modalities to provide complementary information has become commonplace in clinical practice and in preclinical and basic biomedical research. By incorporating the structural information provided by computed tomography (CT) or magnetic resonance imaging (MRI), the ill poseness nature of bioluminescence tomography (BLT) can be reduced significantly, thus improve the accuracies of reconstruction and in vivo quantification. In this paper, we present a small animal imaging system combining multi-view and multi-spectral BLT with MRI. The independent MRI-compatible optical device is placed at the end of the clinical MRI scanner. The small animal is transferred between the light tight chamber of the optical device and the animal coil of MRI via a guide rail during the experiment. After the optical imaging and MRI scanning procedures are finished, the optical images are mapped onto the MRI surface by interactive registration between boundary of optical images and silhouette of MRI. Then, incorporating the MRI structural information, a heterogeneous reconstruction algorithm based on finite element method (FEM) with L 1 normalization is used to reconstruct the position, power and region of the light source. In order to validate the feasibility of the system, we conducted experiments of nude mice model implanted with artificial light source and quantitative analysis of tumor inoculation model with MDA-231-GFP-luc. Preliminary results suggest the feasibility and effectiveness of the prototype system.
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Evaluation of matrix solid-phase dispersion extraction for 11 ?-agonists in swine feed by liquid chromatography with electrospray ionization tandem mass spectrometry.
J Sep Sci
PUBLISHED: 04-11-2014
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A sensitive liquid chromatography with tandem mass spectrometry method was developed for the determination of 11 ?-agonists (clenbuterol, salbutamol, ractopamine, terbutaline, fenoterol, cimaterol, isoxsuprine, mabuterol, mapenterol, clenproperol, and tulobuterol) in swine feed. This rapid, simple, and effective extraction method was based on matrix solid-phase dispersion. The limit of quantification of clenbuterol, cimaterol, mabuterol, salbutamol, terbutaline, mapenterol, clenproperol, and tulobuterol was 1 ?g/kg and that of ractopamine, fenoterol, and isoxsuprine was 2 ?g/kg. The recoveries of ?-agonists spiked in swine feeds at a concentration range of 1-8 ?g/kg were >83.1% with relative standard deviations <9.3%. This rapid and reliable method can be used to efficiently separate, characterize, and quantify the residues of 11 ?-agonists in swine feeds with advantages of simple pretreatment and environmental friendliness.
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Evaluating the impact of environmental temperature on global highly pathogenic avian influenza (HPAI) H5N1 outbreaks in domestic poultry.
Int J Environ Res Public Health
PUBLISHED: 03-16-2014
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The emergence and spread of highly pathogenic avian influenza (HPAI) A virus subtype H5N1 in Asia, Europe and Africa has had an enormously socioeconomic impact and presents an important threat to human health because of its efficient animal-to-human transmission. Many factors contribute to the occurrence and transmission of HPAI H5N1 virus, but the role of environmental temperature remains poorly understood. Based on an approach of integrating a Bayesian Cox proportional hazards model and a Besag-York-Mollié (BYM) model, we examined the specific impact of environmental temperature on HPAI H5N1 outbreaks in domestic poultry around the globe during the period from 1 December 2003 to 31 December 2009. The results showed that higher environmental temperature was a significant risk factor for earlier occurrence of HPAI H5N1 outbreaks in domestic poultry, especially for a temperature of 25 °C. Its impact varied with epidemic waves (EWs), and the magnitude of the impact tended to increase over EWs.
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Biodegradable nanoparticles for intracellular delivery of antimicrobial agents.
J Control Release
PUBLISHED: 03-14-2014
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Biodegradable nanoparticles have emerged as a promising strategy for ferrying antimicrobial agents into specific cells due to their unique properties. This review discusses the current progress and challenges of biodegradable nanoparticles for intracellular antimicrobial delivery to understand design principles for the development of ideal nanocarriers. The intracellular delivery performances of biodegradable nanoparticles for diverse antimicrobial agents are first summarized. Second, the cellular internalization and intracellular trafficking, degradation and release kinetics of nanoparticles as well as their relation with intracellular delivery of encapsulated antimicrobial agents are provided. Third, the influences of nanoparticle properties on the cellular internalization and intracellular fate of nanoparticles and their payload antimicrobial agents are discussed. Finally, the challenges and perspectives of nanoparticles for intracellular delivery of antimicrobial agents are addressed. The review will be helpful to the scientists who are interested in searching for more efficient nanosystem strategies for intracellular delivery of antimicrobial agents.
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A label-free electrochemical DNA sensor using methylene blue as redox indicator based on an exonuclease III-aided target recycling strategy.
Biosens Bioelectron
PUBLISHED: 02-17-2014
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In this work, using methylene blue (MB) as a redox marker and exonuclease III (Exo III) as an amplificatory enzyme, we developed a facile and a label-free electrochemical method for sensitive DNA detection. A double-stranded DNA (dsDNA) probe was prepared by hybridizing two single-stranded DNA (ssDNA) probes. In the ssDNA probes, one ssDNA was guanine bases free and the other one consisted of many unbound guanine bases. MB could be absorbed on the unbound guanine bases owing to the specific interaction between MB and the guanine bases. When the dsDNA probe was challenged with target DNA, it induced a simple Exo III assisted cleavage process, accompanied by the release of the unbound guanine bases. Thus, the amount of MB absorbed on the electrode was much less compared to the initial signal. The detection limit for DNA was found to be as low as 20 fM. Moreover, it could discriminate mismatched DNA from perfectly matched target DNA. This detection method is simple in design, fast in operation and can be applied to detect different DNA sequences.
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Escherichia coli Peritonitis in peritoneal dialysis: the prevalence, antibiotic resistance and clinical outcomes in a South China dialysis center.
Perit Dial Int
PUBLISHED: 02-04-2014
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Escherichia coli (E. coli) peritonitis is a frequent, serious complication of peritoneal dialysis (PD). The extended-spectrum ?-lactamase (ESBL)-producing E. coli peritonitis is associated with poorer prognosis and its incidence has been on continuous increase during the last decades. However, the clinical course and outcomes of E. coli peritonitis remain largely unclear.
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Headspace solid-phase microextraction coupled to gas chromatography for the analysis of aldehydes in edible oils.
Talanta
PUBLISHED: 01-29-2014
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Oxidation has important effects on the quality of edible oils. In particular, the generation of aldehydes produced by the oxidation of oils is one of the deteriorative factors to their quality. The aim of this study was to develop a method to determine the aldehydes as lipid oxidation markers in edible oils. Seven aldehydes generated from lipid oxidation were studied using headspace solid-phase microextraction coupled to gas chromatography with a flame ionization detector. The extraction efficiency of five commercial fibers was investigated and the influence of extraction temperature, extraction time, desorption temperature, and desorption time were optimized. The best result was obtained with 85 ?m carboxen/polydimethylsiloxane, extraction at 50 °C for 15 min and desorption in the gas chromatography injector at 250 °C for 2 min. Under the optimized conditions, the content of hexanal was the highest of the seven aldehydes in all edible oils. The limits of detection for hexanal in the three oils were found to range from 4.6 to 10.2 ng L(-1). The reproducibility of the method was evaluated and the relative standard deviations were less than 8.9%. This developed approach was successfully applied to analyze hexanal in peanut oil, soy oil, and olive oil samples, and these results were compared with those obtained using the thiobarbituric acid-reactive substances (TBARs) method.
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Metabolic disposition and excretion of quinocetone in rats, pigs, broilers, and carp.
Food Chem. Toxicol.
PUBLISHED: 01-16-2014
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Excretion, disposition, and metabolism of [(3)H]-quinocetone in rats, pigs, broilers, and carp following oral administration were investigated. After a single p.o. dose, total radioactivity was rapidly excreted, with ?94% in all species within 14 days. Fecal excretion of radioactivity was 68% and 65% of the administered dose in rats and pigs, respectively, with the remainder excreted in the urine. Six hours after the last of seven daily oral administrations of (3)H-labeled QCT, radioactivity was found to be distributed throughout all tissues, with the majority of radioactivity cleared within 7 days, and elimination was the slowest from the liver and kidney. QCT was extensively metabolized in all of the species, and the primary changes included N-O group reduction, carbonyl group reduction, double bond reduction, and hydroxylation. The major tissue metabolites of QCT were Q2, Q4, Q5, Q8, and Q9 in rats; Q1, Q2, Q3, Q4, and Q5 in pigs; Q1, Q2, Q3, Q4, and Q7 in broilers; and Q1, Q2 in carp. This confirmed the potential link between QCT metabolism through N-O group reduction and its organ toxicity. The results of the present study provide important data that could help understand the relationship between the toxicities and metabolic disposition of QCT.
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Fluorescence determination of acrylamide in heat-processed foods.
Talanta
PUBLISHED: 01-15-2014
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A simple and rapid fluorescence method has been developed for the determination of acrylamide in heat-processed food samples. In the determination, acrylamide is degraded through Hofmann reaction to generate vinyl amine, and pyrrolinone is produced when the vinyl amine reacts with fluorescamine, resulting in a strong fluorescence emission at 480 nm. Hofmann reaction is a key step for the fluorescence determination of acrylaminde, and the reaction conditions are investigated and optimized. Under the optimal conditions, the fluorescence intensity increases with the increase of acrylamide concentrations. The linear range between the fluorescence intensity and the square-root of acrylamide concentrations is from 0.05 ?g mL(-1) to 20 ?g mL(-1) with the correlation coefficient R(2)=0.9935. The detection limit is 0.015 ?g mL(-1) and the recovery for food samples is from 66.0% to 110.6%. In comparison with Specification of Entry&Exit Inspection and Quarantine Bureau of The People?s Republic of China (SN/T 2281-2009), the method showed comparable results and demonstrated the accuracy of the method.
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A proteomic study on molecular mechanism of poor grain-filling of rice (Oryza sativa L.) inferior spikelets.
PLoS ONE
PUBLISHED: 01-01-2014
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Cultivars of rice (Oryza sativa L.), especially of the type with large spikelets, often fail to reach the yield potential as expected due to the poor grain-filling on the later flowering inferior spikelets (in contrast to the earlier-flowering superior spikelets). The present study showed that the size and grain weight of superior spikelets (SS) was greater than those of inferior spikelets (IS), and the carbohydrate supply should not be the major problem for the poor grain-filling because there was adequate amount of sucrose in IS at the initial grain-filling stage. High resolution two-dimensional gel electrophoresis (2-DE) in combination with Coomassie-brilliant blue (CBB) and Pro-Q Diamond phosphoprotein fluorescence stain revealed that 123 proteins in abundance and 43 phosphoproteins generated from phosphorylation were significantly different between SS and IS. These proteins and phosphoproteins were involved in different cellular and metabolic processes with a prominently functional skew toward metabolism and protein synthesis/destination. Expression analyses of the proteins and phosphoproteins associated with different functional categories/subcategories indicated that the starch synthesis, central carbon metabolism, N metabolism and cell growth/division were closely related to the poor grain-filling of IS. Functional and expression pattern studies also suggested that 14-3-3 proteins played important roles in IS poor grain-filling by regulating the activity of starch synthesis enzymes. The proteome and phosphoproteome obtained from this study provided a better understanding of the molecular mechanism of the IS poor grain-filling. They were also expected to be highly useful for improving the grain filling of rice.
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Metabolism, Distribution, and Excretion of Deoxynivalenol with Combined Techniques of Radiotracing, High-Performance Liquid Chromatography Ion Trap Time-of-Flight Mass Spectrometry, and Online Radiometric Detection.
J. Agric. Food Chem.
PUBLISHED: 12-24-2013
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Dispositions of deoxynivalenol (DON) in rats and chickens were investigated, using a radiotracer method coupled with a novel ?-accurate radioisotope counting (?-ARC) radio-high-performance liquid chromatography ion trap time-of-flight tandem mass spectrometry (radio-HPLC-IT-TOF-MS/MS) system. 3?-(3)H-DON was chemically synthesized and orally administrated to both sexes of rats and chickens as single or multiple doses. The results showed that DON was widely distributed and quickly eliminated in all tissues. The highest concentration was found in the gastrointestinal tract at 6 h post-administration. Substantially lower levels were detected in the kidney, liver, heart, lung, spleen, and brain. Three new metabolites were identified tentatively as 10-deoxynivalenol-sulfonate, 10-deepoxy-deoxynivalenol (DOM-1)-sulfonate, and deoxynivalenol-3?-sulfate. Deoxynivalenol-3?-sulfate was a major metabolite in chickens, while the major forms in rats were DOM-1 and DON. Additionally, a higher excretion rate in urine was observed in female rats than in male rats. The differences in metabolite profiles and excretion rates, which suggested diverse ways to detoxify, may relate to the different tolerances in different genders or species.
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Acute kidney injury induced by aristolochic acid in patients with primary glomerular nephritis.
Ren Fail
PUBLISHED: 12-17-2013
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Abstract Background: Acute kidney injury induced by aristolochic acid (AA) might occur in patients with chronic glomerular nephritis (CGN). In this study, the clinical and pathological features of patients with acute aristolochic acid nephropathy (AAN) superimposing CGN (AAN-CGN) were investigated. Methods: Eighteen patients diagnosed as acute AAN were included in this retrospective study, from January 2001 to December 2009. According to the pre-existing CGN, 13 patients were identified as the AAN-CGN group, and 5 isolated AAN patients as the control group. Clinical and pathological features were compared between the two groups. Results: In the AAN-CGN group, six patients complained with gastrointestinal symptoms, such as nausea, vomiting, or loss of appetite. The rest of seven cases were asymptomatic or minimally uncomfortable, who were found with elevated serum creatinine (Scr) in the follow up of CGN. Compared with the control group, the patients in AAN-CGN group had higher levels of serum uric acid, urine n-acetyl-?-d-glucosaminidase, and urine protein excretion (366.2?±?122.8 vs. 218.0?±?125.8??mol/L, p?=?0.037; 9.74?±?4.4 vs. 1.38?±?1.01?g/d, p?=?0.001; 61.2?±?21.9 vs. 27.4?±?15.8??/g???cr, p?=?0.007, respectively). In addition to, the AAN-CGN patients had an absolutely prominent percentage of macromolecule substance in the urine protein electrophoresis (25.0?±?6.32 vs. 15.8?±?7.8%, p?=?0.029). The occurrence of hypokalemia and excretion of aminoaciduria were lower than that in the control group. Pathologically, 84.6% of patients were found with tubular brush border dropping, 30.8% with naked tubular basement membrane, and 15.4% with different stages of vascular lesion. There were no statistical differences in the above-mentioned pathological parameters between the two groups. In the follow-up, 10 patients with AAN-CGN recovered with normal Scr, accounting for 76.9%, which was better than the recovery in the control group. Conclusion: Patients with acute AAN-CGN manifested with a great mass of urine protein excretion, low incidence of hypokalemia and aminoaciduria, however, the tubular-interstitial lesions were similar to the isolated AAN.
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High Risk of Embryo-Fetal Toxicity: Placental Transfer of T-2 Toxin and Its Major Metabolite HT-2 Toxin in BeWo Cells.
Toxicol. Sci.
PUBLISHED: 10-17-2013
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Though T-2 toxin is the most harmful mycotoxin to the fetuses, it remains unclear whether T-2 toxin and its major metabolite, HT-2 toxin, could pass the placenta into the fetus and which kind of placental transport is involved in the passage. To illustrate their placenta transfer mechanism, the uptake and efflux of T-2 and HT-2 toxins across apical membranes of placenta with BeWo cells as a model were studied at different temperatures, pHs, and in the presence of transporter inhibitors with a developed liquid chromatography-tandem mass spectrometry to determine the amount of toxins in both fetal and maternal sites. Higher unidirectional transport of T-2 toxin was observed in the apical-to-basolateral direction than basolateral-to-apical one, whereas HT-2 toxin exhibited similar transport rate from the 2 directions. The main ATP-binding cassette transporters had no effect on the efflux of 2 toxins. Initial uptake of T-2 toxin was sodium dependent and saturable, and the apical uptake was temperature dependent and enhanced under acidic condition. The apical uptake of T-2 toxin was inhibited by metabolic inhibitors and the organic anion and organic cation transporter inhibitors. These results suggested that an active transport mechanism was responsible for the uptake of T-2 toxin, whereas passive diffusion was the principal mechanism for HT-2 toxin transport in the placenta. Taken together, these data characterized the placental transfer of T-2 and HT-2 toxins. The present study offered new ways of reducing the risks of T-2 and HT-2 toxins to both mother and fetuses.
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[MicroRNA-10a accelerates endodermal lineage differentiation of mesenchymal stem cells from human placenta].
Xi Bao Yu Fen Zi Mian Yi Xue Za Zhi
PUBLISHED: 10-10-2013
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To improve the potential of endodermal differentiation of human placenta-derived mesenchymal stem cells (PMSCs) by microRNA-10a (miR-10a)-mediated post-transcriptional regulation of its mRNA targets.
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[Immunomodulatory effects of human placental-derived mesenchymal stem cells on immune rejection in mouse allogeneic skin transplantation].
Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi
PUBLISHED: 09-26-2013
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To investigate the effect of human placental-derived mesenchymal stem cells (PMSCs) on immunological rejection in mouse allogeneic skin transplantation.
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Assessing traffic and polycyclic aromatic hydrocarbon exposure in Montreal, Canada.
Sci. Total Environ.
PUBLISHED: 07-23-2013
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The International Agency for Research on Cancer classifies specific polycyclic aromatic hydrocarbons (PAHs) as probable carcinogens. This study compares two PAH biomarkers and their relationship with geographic information system (GIS) based traffic density (a proxy of PAH exposure), and explores the determinants of the PAH biomarkers.
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Serum sex hormone binding globulin profile and its association with insulin resistance in Chinese peri-menopausal women.
Endokrynol Pol
PUBLISHED: 07-23-2013
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The aim of this study was to measure serum sex hormone binding globulin (SHBG) profile in Chinese peri-menopausal women, and assess its correlation with insulin resistance (IR)-related parameter, namely HOMA-IR, in this special population.
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Development of a liquid chromatography-tandem mass spectrometry with ultrasound-assisted extraction method for the simultaneous determination of sudan dyes and their metabolites in the edible tissues and eggs of food-producing animals.
J. Chromatogr. B Analyt. Technol. Biomed. Life Sci.
PUBLISHED: 06-19-2013
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A liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed for the simultaneous determination of sudan I, sudan II, sudan III, sudan IV, and their metabolites such as 4-aminoazobenzene and ortho-aminoazotoluole in 12 animal derived foods (including the muscle and liver of swine, muscle, liver and skin of chicken and duck, muscle and skin of fish, as well as the eggs of hen and duck). Sample preparation procedure included ultrasound-assisted extraction with acetonitrile, defatting with n-hexane and final clean-up with solid phase extraction (SPE) on Aluminum B cartridges. The detection and quantification of the 6 sudan dyes and their metabolites were performed by a reversed-phase liquid chromatography coupled with electrospray ionization triple quadrupole mass spectrometry (LC/ESI-MS/MS). The CC?s and the CC?s of various samples varied from 0.03?g/kg to 0.12?g/kg, 0.09?g/kg to 0.19?g/kg, respectively. The recoveries of spiked sample from 0.2?g/kg to 0.8?g/kg ranged from 61.9% to 87.4% with the relative standard deviations of less than 19.1%. Performances of the whole analytical procedure meet the criteria established by the European Commission for mass spectrometric detection.
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Susceptibility breakpoint for enrofloxacin against swine Salmonella spp.
J. Clin. Microbiol.
PUBLISHED: 06-19-2013
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Susceptibility breakpoints are crucial for prudent use of antimicrobials. This study has developed the first susceptibility breakpoint (MIC ? 0.25 ?g/ml) for enrofloxacin against swine Salmonella spp. based on wild-type cutoff (COWT) and pharmacokinetic-pharmacodynamic (PK-PD) cutoff (COPD) values, consequently providing a criterion for susceptibility testing and clinical usage of enrofloxacin.
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Development of a liquid chromatography-tandem mass spectrometry with ultrasound-assisted extraction and auto solid-phase clean-up method for the determination of Fusarium toxins in animal derived foods.
J Chromatogr A
PUBLISHED: 06-04-2013
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A liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed for the simultaneous determination of 19 Fusarium toxins and their metabolites including deoxynivalenol (DON), nivalenol (NIV), T-2 toxin (T-2), HT-2 toxin (HT-2), 3-acetyldeoxynivalenol (3-AcDON), 15-acetyldeoxynivalenol (15-AcDON), neosolaniol (NEO), fusarenon-X (F-X), diacetoxyscirpenol (DAS), monoacetoxyscirpenol (MAS), zearalanone (ZAN), zearalenone (ZON), ?-Zearalenol (?-ZOL), ?-Zearalenol (?-ZOL), a-Zearalanol (?-ZAL), ?-Zearalanol (?-ZAL), T-2 triol, T-2 tetraol, deepoxy-deoxynialenol (DOM-1) in the muscle, liver, kidney, fat of swine, bovine and sheep, muscle and liver of chicken, muscle and skin of fish, as well as milk and eggs. Sample preparation procedure includes ultrasound-assisted extraction with acetonitrile/water (90/10, v/v), defatting with n-hexane and final clean-up with auto solid phase extraction (SPE) on Bond Elut Mycotoxin cartridges. The detection and quantification of the analytes were performed by a reversed-phase liquid chromatography coupled with electrospray ionization triple quadrupole mass spectrometry (LC/ESI-MS/MS). DON, NIV, DOM-1, 3-AcDON, 15-AcDON, F-X, ZON, ZAN, ?-ZOL, ?-ZOL, ?-ZAL, ?-ZAL, T-2 triol and T-2 tetraol were detected in a negative ion mode, while T-2 toxin, HT-2 toxin, NEO, DAS and MAS were detected in a positive ion mode. The CC? and CC? of the analytes in different samples varied from 0.16 to 1.37?g/kg and 0.33 to 2.34?g/kg, respectively. The recoveries of spiked sample from 0.5?g/kg to 8?g/kg ranged from 64.8% to 108.2% with the relative standard deviations of less than 19.4%. Performances of the whole analytical procedure meet the criteria established by the European Commission for mass spectrometric detection.
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Evaluation of matrix solid-phase dispersion (MSPD) extraction for multi-fenicols determination in shrimp and fish by liquid chromatography-electrospray ionisation tandem mass spectrometry.
Food Chem
PUBLISHED: 05-03-2013
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A quantitative LC-MS/MS method was developed for the determination of chloramphenicol (CAP), thiamphenicol (TAP), florfenicol (FF) and florfenicol amine (FFA) in shrimp and fish. This rapid simple and effective extraction method was based on matrix solid-phase dispersion (MSPD). The best results were obtained using C18 as dispersant sorbent. The correlation coefficient (r) with each matrix-matched calibration curve is higher than 0.999 at the range of 0.05-0.8?g/kg for CAP and FF, 0.1-1.6?g/kg for FFA and TAP. CC? and CC? of the fenicols upon the method were ranged from 0.01 to 0.09?g/kg and 0.04 to 0.25?g/kg respectively. In the fortified levels recoveries of the four compounds ranged from 83.8% to 98.8% with RSDs lower than 13.7%. The proposed method has been applied successfully to the analysis of CAP, TAP, FF and FFA in shrimp and fish samples, which demonstrates that this method is fast, sensitive, reliable and environmental friendly.
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Cone beam x-ray luminescence computed tomography: a feasibility study.
Med Phys
PUBLISHED: 03-08-2013
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The appearance of x-ray luminescence computed tomography (XLCT) opens new possibilities to perform molecular imaging by x ray. In the previous XLCT system, the sample was irradiated by a sequence of narrow x-ray beams and the x-ray luminescence was measured by a highly sensitive charge coupled device (CCD) camera. This resulted in a relatively long sampling time and relatively low utilization of the x-ray beam. In this paper, a novel cone beam x-ray luminescence computed tomography strategy is proposed, which can fully utilize the x-ray dose and shorten the scanning time. The imaging model and reconstruction method are described. The validity of the imaging strategy has been studied in this paper.
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Identification of parasite-host habitats in Anxiang county, Hunan Province, China based on multi-temporal China-Brazil earth resources satellite (CBERS) images.
PLoS ONE
PUBLISHED: 01-01-2013
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Remote sensing is a promising technique for monitoring the distribution and dynamics of various vector-borne diseases. In this study, we used the multi-temporal CBERS images, obtained free of charge, to predict the habitats of the snail Oncomelania hupensis, the sole intermediate host of schistosomiasis japonica, a snail-borne parasitic disease of considerable public health in China. Areas of suitable snail habitats were identified based on the normalized difference vegetation index (NDVI) and the normalized difference water index (NDWI), and the predictive model was tested against sites (snails present or absent) that were surveyed directly for O. hupensis. The model performed well (sensitivity and specificity were 63.64% and 78.09%, respectively), and with further development, we may provide an accurate, inexpensive tool for the broad-scale monitoring and control of schistosomiasis, and other similar vector-borne diseases.
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Development and validation of an indirect competitive enzyme-linked immunosorbent assay for the screening of tylosin and tilmicosin in muscle, liver, milk, honey and eggs.
J. Agric. Food Chem.
PUBLISHED: 12-15-2011
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Incorrect use of tylosin and tilmicosin could result in allergy and select resistance. To monitor the illegal use of these antibiotics in animals, a monoclonal-based indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) has been established. Several haptens were synthesized and conjugated to carrier protein. Female Balb/c mice were inoculated with the four different conjugates to produce monoclonal antibodies according to the schemes of immunization. Aftercell fusion and culture several times, nine hybridoma cell lines were isolated. Only one, 3C4 that has isotype IgG2a, was selected for detailed study. The cross-reactivity of the monoclonal antibody 3C4 to tylosin and tilmicosin was 100% and 51% respectively. The standard curves based on the tylosin and tilmicosin matrix calibration ranged from 2.5 to 40 ?g L(-1), with an IC(50) value of 6.1 ?g L(-1) and 12.1 ?g L(-1), respectively. The limits of detection of the ic-ELISA ranged from 5.1 ?g kg(-1) to 13.8 ?g kg(-1) in edible animal tissues. The recoveries were 74.1% to 120.7% with less than 18.6% of the coefficient of variation when tylosin and tilmicosin were spiked in various biological matrices with the concentrations of 25.0-200.0 ?g kg(-1). Good correlations between the results of the ic-ELISA and high performance liquid chromatography were observed in the incurred tissues. These results suggest that the ic-ELISA is a sensitive, accurate and low-cost method that would be a useful tool for the screening of the residues of tylosin and tilmicosin in muscle, liver, milk, honey and eggs.
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Simultaneous determination of fluoroquinolones in foods of animal origin by a high performance liquid chromatography and a liquid chromatography tandem mass spectrometry with accelerated solvent extraction.
J. Chromatogr. B Analyt. Technol. Biomed. Life Sci.
PUBLISHED: 09-14-2011
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A confirmatory and quantitative method based on a high performance liquid chromatography UV detector (HPLC-UV) and a liquid chromatography tandem mass spectrometry (LC-MS/MS) with an extraction procedure of accelerated solvent extraction (ASE) has been developed for simultaneous determination of 15 kinds of fluoroquinolones in various animal origin food samples. The sample preparation procedures consist of an extraction step with acetonitrile and a cleaning-up step with Oasis HLB cartridge. Parameters for extraction pressure and temperature, cycle of ASE, clean-up, and analysis procedure have been optimized systematically. The recoveries of FQNs spiked in the tissues as the muscle, liver, kidney of swine, bovine, chicken and fish at a concentration range of 10-800?g/kg were found between 70.6% and 111.1% with relative standard deviations (RSD) less than 15% in HPLC. The LOD and LOQ of the HPLC for the 15 FQNs were 3?g/kg and 10?g/kg, respectively, and those of the LC-MS/MS were 0.3 and 1?g/kg, respectively. These rapid and reliable methods can be used to efficiently separate, characterize and quantify the residues of 15 FQNs (Marbofloxacin, Enoxacin, Fleroxacin, Ofloxacin, Pefloxacin, Lomefloxacin, Danofloxacin, Enrofloxacin, Orbifloxacin, Cinoxacin, Gatifloxacin, Sarafloxacin, Difloxacin, Nalidixic Acid, Flumequine) in food of animal origin.
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A new density-ratio based approach for patient-specific biomedical monitoring.
Conf Proc IEEE Eng Med Biol Soc
PUBLISHED: 08-29-2011
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In order to denote the abnormalities of the patients, we propose a novel approach to detect anomaly in biomedical monitoring using density ratio values as the Patient Status Index (PSI). The key idea of the proposed method is to define the ratio of training and testing data densities, where training dataset only consist of normal data and testing dataset consist of both normal and abnormal data, and identify irregular samples for testing patients dataset. Furthermore, we define four inequalities to denote the interval values of density ratio and give the corresponding status for patients. In addition, the applied Kullback-Leibler based algorithm for calculating density ratio values without involving density estimation is equipped with a cross validation (CV) model selection procedure, allowing us to objectively optimize values of tuning parameters. We select training and testing data from Physionet database to do our pilot experiment. The experimental results for 11901 beats show that the density-ratio based approach work very well in terms of specificity and sensitivity.
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Health status detection for patients in physiological monitoring.
Conf Proc IEEE Eng Med Biol Soc
PUBLISHED: 08-29-2011
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A primary difficulty in physiological monitoring is detecting changes of health status for patients. In order to address this difficulty, we propose a new framework in patient-specific physiological monitoring by defining a density ratio using the training density and testing density to denote the changes of patient status, such as health, sub-health and abnormalities. We use a Least Square-based algorithm to estimate density ratio parameters without involving density estimation. For verifying the availability and efficacy of the proposed framework, we apply our approach to physiological monitoring data (11901 beats) from the Physionet database to do the pilot experiments. Results demonstrate that the approach is effective in detecting the patient status.
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Metabolism of cyadox by the intestinal mucosa microsomes and gut flora of swine, and identification of metabolites by high-performance liquid chromatography combined with ion trap/time-of-flight mass spectrometry.
Rapid Commun. Mass Spectrom.
PUBLISHED: 07-19-2011
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Cyadox (CYX), 2-formylquinoxaline-1,4-dioxide cyanoacetylhydrazone, is an antimicrobial and growth-promoting feed additive for food-producing animals. To reveal biotransformation of CYX in swine intestine, CYX was incubated with swine intestinal microsomes and mucosa in the presence of an NADPH-generating system and swine ileal flora and colonic flora, respectively. The metabolites of CYX were identified using high-performance liquid chromatography combined with ion trap/time-of-flight mass spectrometry (LC/MS-ITTOF). Structural elucidation of the metabolites was precisely performed by comparing their changes in molecular mass, full scan MS/MS spectra and accurate mass measurements with those of the parent drug. Finally, seven metabolites were identified as follows: three reduced metabolites (cyadox 1-monoxide (Cy1), cyadox 4-monoxide (Cy2) and bisdesoxycyadox (Cy4)); hydroxylation metabolite (3-hydroxylcyadox 1-monoxide (Cy3)); hydrolysis metabolite of the amide bond (N-decyanoacetyl cyadox (Cy5)); a hydrogenation metabolite (11,12-dihydro-bisdesoxycyadox (Cy6)) and a side-chain cleavage metabolite (2-hydromethylquinoxaline (Cy7)). Only one metabolite (Cy1) was found in intestinal microsomes. Cy1, Cy2 and Cy4 were detected in intestinal mucosa, ileal and colonic flora. In addition, Cy3 and Cy5 were only obtained from ileal flora, and Cy6 and Cy7 alone were observed in colonic bacteria. The results indicated that N?O group reduction was the main metabolic pathway of CYX metabolism in swine ileal flora, intestinal microsomes and mucosa. New metabolic profiles of hydrogenation and cleavage on the side chain were found in colonic bacteria. Among the identified metabolites, two new metabolites (Cy6, Cy7) were detected for the first time. These studies will contribute to clarify comprehensively the metabolism of CYX in animals, and provide evidence to explain the pharmacology and toxicology effects of CYX in animals.
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The c-Abl-MST1 signaling pathway mediates oxidative stress-induced neuronal cell death.
J. Neurosci.
PUBLISHED: 07-01-2011
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Oxidative stress influences cell survival and homeostasis, but the mechanisms underlying the biological effects of oxidative stress remain to be elucidated. The protein kinase MST1 (mammalian Ste20-like kinase 1) plays a major role in oxidative stress-induced cell death in primary mammalian neurons. However, the mechanisms that regulate MST1 in oxidative stress responses remain largely unknown. In the present study, we demonstrate that the protein kinase c-Abl phosphorylates MST1 at Y433, which triggers the stabilization and activation of MST1. Inhibition of c-Abl promotes the degradation of MST1 through C terminus of Hsc70-interacting protein (CHIP)-mediated ubiquitination, and thereby attenuates cell death. Oxidative stress induces the c-Abl-dependent tyrosine phosphorylation of MST1 and increases the interaction between MST1 and FOXO3 (Forkhead box O3), thereby activating the MST1-FOXO signaling pathway, leading to cell death in both primary culture neurons and rat hippocampal neurons. The identification of the c-Abl tyrosine kinase as a novel upstream activator of MST1 suggests that the c-Abl-MST1 signaling cascade plays an important role in cellular responses to oxidative stress.
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Comparison of the substrate kinetics of pig CYP3A29 with pig liver microsomes and human CYP3A4.
Biosci. Rep.
PUBLISHED: 05-05-2011
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CYP (cytochrome P450) 3A29 in pigs could be an important candidate gene responsible for xenobiotic metabolism, similar to CYP3A4 in humans. Accordingly, the tissue expression of CYP3A29 mRNA in domestic pigs has been determined by a real-time PCR. The enzymatic properties of CYP3A29, CYP3A4 and PLM (pig liver microsomes) were compared by kinetic analysis of TST (testosterone) 6?-hydroxylation and NIF (nifedipine) oxidation. CYP3A29 mRNA was highly expressed in the liver and small intestines of domestic pigs. The CYP3A29 enzyme expressed in Sf9 cells had the same TST-metabolizing activity as human CYP3A4 based on their roughly equal in vitro intrinsic clearance values. The affinity of CYP3A29 for NIF was lower than that of CYP3A4 but higher than that of PLM. KET (ketoconazole) was a more potent inhibitor of TST 6?-hydroxylation and NIF oxidation activities of CYP3A29 than TAO (troleandomycin). These findings indicate that pig CYP3A29 is similar to human CYP3A4 in both extent of expression and activity. The results reported in this paper provide a basis for future in vitro toxicity and metabolism studies.
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An association study of the genetic polymorphisms in 13 neural plasticity-related genes with semantic and episodic memories.
J. Mol. Neurosci.
PUBLISHED: 05-04-2011
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Semantic and episodic memories were two different attributes of long-term memory. In the past few years, plenty of physiological evidence has indicated that neural plasticity is involved in the formation of long-term memory. In the present study, we hypothesized that some functional variants of neural plasticity-related genes were related to episodic and semantic memories. To confirm this hypothesis, we examined the relationship of 13 plasticity-related genes with episodic and semantic memories. The results indicated that there was a statistically significant difference in semantic memory scores among the three genotype groups of T267C in 5-HT ( 6 ) (? (2)?=?16.638, p?=?0.0002). However, the functional variations in BDNF, COMT, DBH, DRD ( 2 ), DRD ( 3 ), DRD ( 4 ), MAOA, TPH ( 2 ), 5-HT ( 2A ), GRM ( 1 ), and GRIN2B had no observable effects on the memories. Our preliminary results confirm the hypothesis that a small number of functional variants of the neural plasticity-related genes, such as T267C in 5-HT ( 6 ), play important roles in human specific memory.
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Development of a high performance liquid chromatography method and a liquid chromatography-tandem mass spectrometry method with the pressurized liquid extraction for the quantification and confirmation of sulfonamides in the foods of animal origin.
J. Chromatogr. B Analyt. Technol. Biomed. Life Sci.
PUBLISHED: 04-22-2011
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The residues of sulfonamides (SAs) in the foods of animal origin are of the major concern because they are harmful to the consumers health and could induce pathogens to develop resistance. Rapid and efficient determination methods are urgently in need. A quantitative high performance liquid chromatography method (HPLC) and a confirmative liquid chromatography-tandem mass spectrometry (LC-MS/MS) for the simultaneous determination of 18 sulfonamides such as sulfamidinum, sulfanilamide, sulfisomidine, sulfadiazine, sulfapyridine, sulfathiazole, sulfamerazine, sulfadimidine, sulfamethoxypyridazine, sulfamethoxydiazine, sulfisoxazole, sulfachloropyridazine, sulfamethoxazole, sulfamonomethoxine, sulfadoxine, sulfaclozine, sulfadimethoxine, sulfaquinoxaline in the muscles, livers and kidneys of swine, bovine and chicken were developed and validated. The sample preparation procedures included a pressurized liquid extraction (PLE) with acetonitrile conducted at elevated temperature (70°C) and pressure (1400 psi). After clean-up with hydrophilic-lipophilic balance cartridge, the extraction solution was concentrated and analyzed by HPLC and LC-MS/MS analysis. 18 SAs were separated by the HPLC with a Zorbax SB-Aq-C18 column and the mobile phase of methanol/acetonitrile/1% acetic acid with a gradient system. The wavelength of UV for the HPLC detection was set at 285 nm. The LC-MS/MS analysis was achieved with a Hypersil Golden column and the mobile phase of acetonitrile and 0.1% formic acid aqueous solution with two gradient systems. The Limits of detection (LOD) and the limits of quantitation (LOQ) were 3 ?g/kg and 10 ?g/kg, respectively, for both of the HPLC and LC-MS/MS. Linearity was obtained with an average coefficient of determination (R) higher than 0.9980 over a dynamic range from the LOQ value up to 5000 ?g/kg. The recoveries of the methods range from 71.1% to 118.3% with the relative standard derivation less than 13%. The peaks of interest with no interferences were observed throughout the chromatographic run. The sample pretreatment provided efficient extraction and cleanup that enables a sensitive and rugged determination of 18 SAs, the obtained results revealed that PLE, in comparison with other sample preparation methods applied, has significantly higher efficacy for SAs isolation from animal tissues.
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Studies on the supramolecular interaction between dimethomorph and disulfide linked ?-cyclodextrin dimer by spectrofluorimetry and its analytical application.
J. Agric. Food Chem.
PUBLISHED: 04-19-2011
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The supramolecular interaction of disulfide linked ?-cyclodextrin (?-CD) dimer and dimethomorph has been studied by spectrofluorimetry. Based on the significant enhancement of the fluorescence intensity of dimethomorph, a new spectrofluorimetric method with high sensitivity and selectivity was developed for the determination of dimethomorph in bulk aqueous in the presence of the disulfide linked ?-CD dimer. The inclusion complexation behavior of ?-CD dimer with dimethomorph was studied in a KH(2)PO(4)-H(3)PO(4) buffer solution of pH 3.86 at room temperature. The apparent association constant of the complex was 2.25 × 10(4) L/mol. The linear range was 12-7500 ng/mL with the detection limit 3.70 ng/mL, and the limit of quantification was 12.4 ng/mL. The proposed method had been successfully applied to the determination of dimethomorph residues in vegetables with recoveries of 89.0-115%.
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Development of a liquid chromatography-tandem mass spectrometry with pressurized liquid extraction method for the determination of benzimidazole residues in edible tissues.
J. Chromatogr. B Analyt. Technol. Biomed. Life Sci.
PUBLISHED: 03-30-2011
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A confirmatory and quantitative method of liquid chromatography-tandem mass spectrometry (LC-MS/MS) combined with a pressure liquid extraction (PLE) was developed for the determination of 11 benzimidazole and 10 metabolites of albendazole, fenbendazole and mebendazole in the muscles and livers of swine, cattle, sheep and chicken. For sample preparation, we used an automated technique of PLE method. The optimum extraction conditions were obtained using an 11 ml Accelerated Solvent Extraction (ASE) cells, acetonitrile/hexane as the extraction solvent. HPLC analysis was performed on a C18 column with gradient elution using acetonitrile and 5 mmol l(-1) formic ammonium as mobile phase. The analytes were detected in the positive ion multiple reaction monitoring (MRM) mode by the LC-ESI-MS/MS analysis. The recoveries of benzimidazole (BZDs) spiked at the levels of 0.5 ?g kg(-1) ranged from 70.1% to 92.7%; the between-day relative standard deviations were no more than 10%. The limits of quantification were 0.02-0.5 ?g kg(-1). The optimized method was successfully applied to monitor real samples containing BZDs, demonstrating the method to be simple, fast, robust and suitable for identification and quantification of BZDs residues in animal products.
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Risk signals of an influenza pandemic caused by highly pathogenic avian influenza subtype H5N1: spatio-temporal perspectives.
Vet. J.
PUBLISHED: 02-17-2011
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Highly pathogenic avian influenza (HPAI) subtype H5N1 is a trans-boundary animal disease that has crossed the animal-human species barrier and over the past decade has had a considerable impact on the poultry industry, wild bird populations and on human health. Understanding the spatio-temporal patterns of H5N1 outbreaks can provide visual clues to the dynamics of disease spread and of areas at risk, and thus improve the cost-effectiveness of disease control and prevention. This study describes the characteristics and investigates the temporal, spatial and space-time dynamics of H5N1 outbreaks in domestic poultry between December 2003 and December 2009 using a global database. The study found that the start date of the epidemic wave was postponed, the duration of the epidemic was prolonged and its magnitude reduced over time, but the disease transmission cycle was not efficiently interrupted. Two hot-spot regions of H5N1 outbreaks were identified: well-documented locations in East and Southeast Asia, as well as a novel location at the boundaries of Europe and Africa, where enhanced surveillance should be conducted. The risk of a pandemic due to H5N1 remains high.
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Variations in 5-HT2A influence spatial cognitive abilities and working memory.
Can J Neurol Sci
PUBLISHED: 02-16-2011
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5-hydroxytryptamine receptor 2A (5-HT2A) participates in diverse psychiatric disorders by regulating the activity of serotonin. Some previous studies have also suggested that the receptor is involved in cognitive abilities of disease groups. We hypothesize that some functional genetic variants in 5-HT2A have certain specific influences on cognitive abilities in a normal population.
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Development of a high-performance liquid chromatography method for the simultaneous quantification of four organoarsenic compounds in the feeds of swine and chicken.
J. Chromatogr. B Analyt. Technol. Biomed. Life Sci.
PUBLISHED: 02-07-2011
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A high-performance liquid chromatography (HPLC) method with UV detection was developed for the simultaneous determination of arsanilic acid, roxarsone, nitarsone, and carbarsone in the feeds of swine and chicken. Feed samples were extracted with methanol/1% acetic acid (90:10, v/v) in an ultrasonic bath and the protein was precipitated with 2% Cu(2)SO(4). The samples were further purified by solid phase extraction (SPE) on SAX cartridges. Separation was performed on a Zorbax SB-Aq C18 HPLC column using an isocratic procedure with methanol and 1% acetic acid (3:97, v/v) at a flow-rate of 0.7 mL min(-1), and the UV detector was set at a wavelength of 260 nm. The recoveries of organoarsenic compounds spiked at levels of 2, 20 and 200 ?g g(-1) ranged from 81.2% to 91.3%; the inter-day relative standard deviation values were less than 7.0%. The limits of quantification for four organoarsenic compounds were 1.0-2.0 ?g g(-1). This simple and fast method could be applied to the determination of multi-residues of organic arsenic compounds in animal feeds.
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Nonparametric evaluation of dynamic disease risk: a spatio-temporal kernel approach.
PLoS ONE
PUBLISHED: 01-31-2011
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Quantifying the distributions of disease risk in space and time jointly is a key element for understanding spatio-temporal phenomena while also having the potential to enhance our understanding of epidemiologic trajectories. However, most studies to date have neglected time dimension and focus instead on the "average" spatial pattern of disease risk, thereby masking time trajectories of disease risk. In this study we propose a new idea titled "spatio-temporal kernel density estimation (stKDE)" that employs hybrid kernel (i.e., weight) functions to evaluate the spatio-temporal disease risks. This approach not only can make full use of sample data but also "borrows" information in a particular manner from neighboring points both in space and time via appropriate choice of kernel functions. Monte Carlo simulations show that the proposed method performs substantially better than the traditional (i.e., frequency-based) kernel density estimation (trKDE) which has been used in applied settings while two illustrative examples demonstrate that the proposed approach can yield superior results compared to the popular trKDE approach. In addition, there exist various possibilities for improving and extending this method.
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No observable relationship between the 12 genes of nervous system and reasoning skill in a young Chinese Han population.
Cell. Mol. Neurobiol.
PUBLISHED: 01-15-2011
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Reasoning skill is an advanced cognitive ability which is needed for drawing inferences from given information. It is well known that the ability depends on the neural network of the frontal and parietal brain regions. In this study, we hypothesized that some genes involved in neurotransmitter systems were related to reasoning skill. To confirm this hypothesis, we examined the effects of 13 genes (BDNF, NRSF, COMT, DBH, DRD(2), DRD(3), DAT(1), MAOA, GRM(1), GRIN2B, TPH(2), 5-HT(2A), and 5-HT(6)) in neurotransmitter systems on the non-verbal reasoning and verbal reasoning skills. The results indicated there were on significant effects of the 17 functional variants of these genes on the performance of non-verbal reasoning and verbal analogical reasoning skills (?(2) > 3.84, df = 1, P > 0.05). This study suggests that some of the functional variations in BDNF, COMT, DBH, DRD(2), DRD(3), MAOA, 5-HT(2A), 5-HT(6), GRM(1), and GRIN2B have no observable effects on the certain reasoning skills in a young healthy Chinese Han population.
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Clinicopathological features and prognosis of Chinese patients with acute post-streptococcal glomerulonephritis.
Nephrology (Carlton)
PUBLISHED: 10-02-2010
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To investigate clinicopathological and prognostic differences between adults and children with acute post-streptococcal glomerulonephritis (APSGN).
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Development of a liquid chromatography-tandem mass spectrometry with pressurized liquid extraction for determination of glucocorticoid residues in edible tissues.
J. Chromatogr. B Analyt. Technol. Biomed. Life Sci.
PUBLISHED: 09-08-2010
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A multi-residues method using pressurized liquid extraction (PLE) and liquid chromatography combined with mass spectrometry (LC-MS/MS) has been developed for determination of eight glucocorticoids (prednisone, prednisolone, hydrocortisone, methylprednisolone, dexamethasone, betamethasone, beclomethasone, fludrocortisone) in muscle of swine, cattle, and sheep. Parameters affecting PLE extraction including extraction solvent, extraction temperature, extraction pressure and extraction cycles were optimized. The optimized method employed 11 ml extraction cells, hexane-ethyl acetate (50:50, v/v) as extraction solvent, 1500 psi of extraction pressure and 50°C of extraction temperature. The samples were detected by LC-ESI-MS/MS in negative mode with selected reaction monitoring (SRM) mode. The recovery of glucocorticoids spiked at levels of 0.5-6 ?g kg(-1) ranged from 70.1% to 103.1%; the between-day relative standard deviations were no more than 9.6%. The limits of quantification were 0.5-2 ?g kg(-1) in muscle. The results demonstrated that the method is simple, fast, robust, and suitable for identification and quantification of glucocorticoids residues in foods of animal origin.
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Spatio-temporal data comparisons for global highly pathogenic avian influenza (HPAI) H5N1 outbreaks.
PLoS ONE
PUBLISHED: 08-14-2010
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Highly pathogenic avian influenza subtype H5N1 is a zoonotic disease and control of the disease is one of the highest priority in global health. Disease surveillance systems are valuable data sources for various researches and management projects, but the data quality has not been paid much attention in previous studies. Based on data from two commonly used databases (Office International des Epizooties (OIE) and Food and Agriculture Organization of the United Nations (FAO)) of global HPAI H5N1 outbreaks during the period of 2003-2009, we examined and compared their patterns of temporal, spatial and spatio-temporal distributions for the first time. OIE and FAO data showed similar trends in temporal and spatial distributions if they were considered separately. However, more advanced approaches detected a significant difference in joint spatio-temporal distribution. Because of incompleteness for both OIE and FAO data, an integrated dataset would provide a more complete picture of global HPAI H5N1 outbreaks. We also displayed a mismatching profile of global HPAI H5N1 outbreaks and found that the degree of mismatching was related to the epidemic severity. The ideas and approaches used here to assess spatio-temporal data on the same disease from different sources are useful for other similar studies.
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Determination of sodium nifurstyrenate and nitrovin residues in edible food by liquid chromatography-tandem mass spectrometry after ultrasound-assisted extraction.
J. Chromatogr. B Analyt. Technol. Biomed. Life Sci.
PUBLISHED: 08-13-2010
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A specific and sensitive method based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) has been developed for the determination of nitrovin and sodium nifurstyrenate residues in muscle and liver of swine and chicken and in muscle of fish. Sample preparation procedure includes ultrasound-assisted extraction with acetonitrile, defatting with n-hexane and final clean-up with solid phase extraction (SPE) on Oasis HLB cartridges. The analytes were detected in multiple reaction monitoring (MRM) under negative scan mode acquiring two diagnostic product ions for sodium nifurstyrenate and under positive mode for nitrovin. The averaged decision limits (CC?; ? 1%) ranged 0.09-0.26 ?g/kg while the detection capability (CC?; ? 5%) was 0.33-0.97 ?g/kg in the tissues. Reasonable recoveries (71-110%) spiked in muscle and liver showed excellent relative standard deviation (RSD). The validated method was simple, rapid, sensitive, and complied with the regulations for the determination of nitrovin and sodium nifurstyrenate residues in food matrices.
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Development of a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the quantification of glucocorticoid residues in edible tissues of swine, cattle, sheep, and chicken.
Food Addit Contam Part A Chem Anal Control Expo Risk Assess
PUBLISHED: 07-27-2010
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A confirmatory and quantitative method using liquid chromatography-tandem mass spectrometry (LC-MS/MS) to determine the presence of eight glucocorticoids (prednisone, prednisolone, hydrocortisone, methylprednisolone, dexamethasone, betamethasone, beclomethasone, and fludrocortisone) in the muscles and livers of swine, cattle, and sheep and the muscle of chicken is described. After deconjugation in alkali media, samples were extracted with ethyl acetate for glucocorticoids followed by solid-phase extraction clean-up and reconstitution in the LC mobile phase. The hydrolysis procedure with sodium hydroxide was used to reduce handling time. A single-step solid-phase extraction method was optimized which is suitable for the clean-up of the compounds of interest in many diverse tissue matrices. LC separations were performed on a C(18) column with gradient elution using acetonitrile and water (containing 0.2% formic acid) and the two epimers betamethasone and dexamethasone were successfully separated. LC-electrospray ionization (ESI)-MS/MS in negative mode with selected reaction monitoring (SRM) mode was performed to improve method sensitivity and reduce matrix interference. Two SRM transitions were used for each compound. The recovery of glucocorticoids spiked at levels of 0.5-16 microg kg(-1) ranged from 55% to 107%; the between-day relative standard deviations were no more than 15%. The limits of quantification were 0.5-2.0 microg kg(-1) in muscle and 1-4 microg kg(-1) in liver. The optimized procedure was successfully applied to monitor the food at the 2008 Summer Olympics Games in Beijing, China, demonstrating the method to be simple, fast, robust, and suitable for identification and quantification of glucocorticoids residues in foods of animal origin.
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[Construction and identification of recombinant retroviral vector of human ngn3 gene and its packaging cell line].
Sheng Wu Gong Cheng Xue Bao
PUBLISHED: 06-26-2010
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In order to construct the recombinant retrovirus vector of human ngn3 gene and its packaging cell line, we successfully amplified the open reading frame (ORF) of ngn3 gene from human fetal pancreatic tissue by RT-PCR. The PCR products of human ngn3 gene was subcloned into pMD18-T vectors and sequenced. Results showed that its sequence was fully consistent with the ngn3 gene published in GenBank(GenBank Accession No. BC126468). The correct fragment was digested by EcoR I and Hpa I from recombinant pMD18-T vector and inserted into the same restriction enzyme sites of retroviral vector pMSCV-neo. We got recombinant retrovirus vector pMSCV-ngn3, which was identified by double restriction enzyme digestion and then transfected into PT67 cells by lipofectamine 2000. We established the PT67-ngn3 packaging cell line by G418 selection, which was detected by RT-PCR and immunohistochemistry staining. The detection results showed that the Ngn3 expressed at the mRNA and protein level in the packaging cell line. RT-PCR detection and electronic microscope analysis showed that the recombinant retroviral vector pMSCV-ngn3 was packaged into infectious virus particles and released into the supernatant of the cells. These results demonstrated that a PT67-ngn3 packaging cell line was successfully established, and this could facilitate the study of differentiation of the human fetal pancreatic progenitor cells into insulin-producing cells by using the ngn3 gene.
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Development of a high-performance liquid chromatography method to monitor the residues of benzimidazoles in bovine milk.
J. Chromatogr. B Analyt. Technol. Biomed. Life Sci.
PUBLISHED: 06-18-2010
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A reversed-phase high-performance liquid chromatography with ultraviolet (UV) detection was developed that can determine 11 benzimidazole (BZDs) and 10 metabolites of albendazole, fenbendazole and mebendazole in bovine milk. Samples were extracted with acetonitrile and purified by mixed-mode cation exchange (MCX) solid phase extraction cartridges. LC separations were performed on a C(18) column with gradient elution using acetonitrile and ammonium acetate solution. The UV-detection was set at 292nm. The method is very sensitive to each analyte with limits of quantification (LOQs) of lower than 10?gkg(-1). The recoveries of the BZDs and their metabolites spiked in milk were more than 78% with between-day relative standard deviation values less than 16% at the concentration of 10, 50 and 100?gkg(-1). The method developed has been successfully applied to monitoring real samples containing BZDs, which demonstrated that it is a simple, fast and robust method, and could be used as a regulatory toll to determine the residues of BZDs in milk.
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Alterations in mitochondrial function and spermatozoal motility in goat spermatozoa following incubation with a human lysozyme plasmid.
Anim. Reprod. Sci.
PUBLISHED: 05-04-2010
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Spermatozoa mediated gene transfer has become a promising technology to generate transgenic animals with disease resistance. However, exogenous DNA invasion may cause changes in spermatozoon natural defense system which result in spermatozoon dysfunction.The objective of this study was to investigate the changes of mitochondrial function and motility in goat spermatozoa after pre-incubation and incubation with and without the human lysozyme plasmid pFLAG-hLY. The results demonstrated that human lysozyme plasmid pFLAG-hLY could bind to the surface of the spermatozoon membrane at 186,000 copies/spermatozoa and incorporate to spermatozoon nucleus at 78 copies/spermatozoa after incubation. However, the treated spermatozoon samples showed a significant lower motility (29.7+/-2.2% vs. pre-incubation control 48.0+/-1.4% and incubation control 54.5+/-1.5%, P < 0.05), and percentage of rapid progressive motile spermatozoa(16.4+/-2.4% vs. pre-incubation control 31.4+/-0.6% and incubation control 37.0+/-0.5%,P < 0.01). Meanwhile, the incubation with plasmids caused significant reduction of mitochondrial membrane potential (31.44+/-2.17% vs. pre-incubation control 51.79+/-2.08% and incubation control 58.81+/-1.76%, P < 0.05). In addition, dichlorofluorescin relative fluorescence intensity (32.81+/-2.41%) and malondialdehyde levels (2.18+/-0.21 nM/108 spermatozoa), which represents mitochondrial function, showed a significant increase after incubation (P < 0.05). The cytochrome c release from the mitochondrial inner membrane space, and enzymatic activities of caspase-3 (0.086+/-0.024) and caspase-9 (0.083+/-0.019)(P < 0.05) also increased, in which resulted in spermatozoon dysfunction. In conclusion, this study confirmed that goat spermatozoa could capture human lysozyme plasmid pFLAG-hLY,but the incubation with the plasmids resulted in a decrease of spermatozoa motility and partial rupture of mitochondrial membrane, and further prompted the expression of cytochrome c, and generation of oxidative stress in vitro and finally led to spermatozoon dysfunction.
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Development of a high performance liquid chromatography method and a liquid chromatography-tandem mass spectrometry method with pressurized liquid extraction for simultaneous quantification and confirmation of cyromazine, melamine and its metabolites in f
Anal. Chim. Acta
PUBLISHED: 04-27-2010
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Simple and sensitive methods have been developed for simultaneous detection of cyromazine, melamine and their metabolites (ammeline, ammelide and cyanuric acid) in samples of animal origins. These include a high performance liquid chromatography (HPLC) method and a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method and are useful in regular monitoring and in toxicity studies of these molecules. Representative samples used in this study include muscles and livers of swine, bovine, sheep and chicken, kidneys of swine, bovine and sheep, and milk powder. A new sample preparation procedure with pressurized liquid extraction (PLE) at 1400psi and 70°C was investigated. Quantification of these five compounds by HPLC was achieved using an APS-2 column with UV detection at 230 nm. Limit of detection (LOD) was at 10 ?gkg(-1), and limit of quantification (LOQ) was at 40 ?gkg(-1). Recoveries of the five analytes in spiked samples ranged from 72.2% to 115.4% with RSD less than 12%. Confirmatory analysis of the analytes was performed using LC-MS/MS in selected reaction monitoring (SRM) mode. The LOD and LOQ were 5 ?gkg(-1) and 15 ?gkg(-1), respectively. This is the first simultaneous analysis of cyromazine, melamine, ammeline, ammelide and cyanuric acid residues in complex tissue samples using PLE and HPLC. It is expected that these methods will find many practical applications in evaluating the safety of cyromazine, melamine and their metabolites.
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Association analysis between 12 genetic variants of ten genes and personality traits in a young chinese Han population.
J. Mol. Neurosci.
PUBLISHED: 03-04-2010
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Some genes involved in neurotransmission synthesis and transmission have been hypothesized to affect personality traits. To investigate the possible roles of these genes in personality traits of 16 Personality Factor Questionnaire, we performed a population-based study in a young Chinese Han cohort. In the study, we selected some functional variations in ten candidate genes (COMT, DBH, DRD(2), DRD(3), DAT, MAOA, GRM(1), GRIN2B, 5-TH(2A), and 5-TH(6)) encoding components in dopamine, glutamate, and 5-hydroxytryptamine pathways. The results showed the T102C in 5-TH(2A) was associated with X3 (emotional and quiet alertness) and B (reasoning) (F = 4.71 and 6.23; p = 0.009 and 0.002), Val158Met in COMT with E (dominance) (F = 7.01; p = 0.0009), while the variations in DBH, DRD(2), DRD(3), MAOA, GRM(1), GRIN2B, and 5-TH(6) were not associated with any of the personality traits. This finding suggests that T102C in 5-TH(2A) and Val158Met in COMT play roles in some human personality traits.
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Late onset lupus nephritis: analysis of clinical manifestations and renal pathological features in Chinese patients.
Rheumatol. Int.
PUBLISHED: 02-27-2010
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The objectives of the study are to analyze the clinical and pathological features of 35 Chinese patients with late onset lupus nephritis (LN) in a single center. All the LN patients followed-up in our lupus clinic center from 1986 to 2008 were enrolled in this retrospective study. Thirty-five patients with a disease onset beyond the age of 50 years were identified. One hundred systemic lupus erythematosus (SLE) patients who had their disease onset before the age of 50 years were randomly recruited as controls. All of them received renal biopsy. The histological classifications were categorized according to 2003 International Society of Nephrology/Renal Pathology Society (ISN/RPS) classification. All of patients were Han Chinese. The mean age of onset of SLE for late onset and the control groups were 55.7 ± 6.5 years (range: 50-76) and 28.9 ± 7.6 years (range:18-48).The female to male ratio was smaller in the late onset SLE group, 2.9-1, compared with 7.3-1 in the control. The patients with hypertension in late onset LN were much more than that in control group. The renal histological classes showed no significant difference between the two groups. Classes IV, V, IV + V were common in late onset LN patients. There were no significant differences in extra renal manifestations except for a lower prevalence of malar rash, a higher leukopenia and skin vasculitis in the late onset patients. As to the immunological features, serum antineutrophil cytoplasmic antibodies (ANCA) and SSA positivity were more common in late onset LN patients. The patients with hypertension in late onset LN were much more than that in control group. The renal histological classes showed no significant difference between the two groups. Leukopenia and serum ANCA were more common. The results suggest a more severity of the disease in late onset LN.
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Simultaneous determination of amitraz and its metabolite residue in food animal tissues by gas chromatography-electron capture detector and gas chromatography-mass spectrometry with accelerated solvent extraction.
J. Chromatogr. B Analyt. Technol. Biomed. Life Sci.
PUBLISHED: 01-25-2010
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A new method has been developed for determination and confirmation of amitraz and its main metabolite, 2,4-dimethylaniline, in food animal tissues using gas chromatography-electron capture detector (GC-ECD) and gas chromatography-mass spectrometry detector (GC-MS). This method is based on a new extraction procedure using accelerated solvent extraction (ASE). It consists of an n-hexane/methanol extraction step, a cleaning-up step by BakerBond octadecyl C(18) silica bonded cartridge, hydrolysis and derivatization to 2,4-dimethyl-7-F-butyramide for GC-ECD analysis. For confirmation using GC-MS, hydrolysis and derivatization were not needed. Parameters for extraction pressure, temperature and cycle of ASE, clean-up, derivatization and analysis procedure have been optimized. Spike recoveries from 50 to 300 microg/kg levels were found to be between 72.4 and 101.3% with relative standard deviation less than 11.5% in GC-ECD, from 5 to 20 microg/kg levels were found to be between 77.4 and 107.1% with relative standard deviation less than 11.6% in GC-MS. The LOD and LOQ are 5 and 10 microg/kg, respectively, for these two analytes using GC-ECD. For GC-MS, LOD and LOQ were 2 and 5 microg/kg, respectively. The rapid and reliable method can be used for characterization and quantification of residues of amitraz and its main metabolite, 2,4-dimethylaniline, in liver and kidney samples of swine, sheep and bovine.
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[Cloning of bovine sox2 gene and construction of its retrovirus vector].
Sheng Wu Gong Cheng Xue Bao
PUBLISHED: 12-02-2009
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In order to construct the recombinant retrovirus vector of bovine sox2 gene and obtain infectious retroviral particles, we successfully amplified the ORF (open reading frame) of bovine sox2 gene from the primodial genital ridges of bovine embryo by RT-PCR. The cDNA of ORF was subcloned to pMD18-T vectors and verified that its sequence was highly homologous to the GenBank counterpart (GenBank Accession No. NM-001105463) by sequencing. The correct fragment was digested by EcoR I/Bgl II from recombinant pMD18-T vector and inserted into the same restriction sites f retroviral vector pMSCVneo. We got recombinant retrovirus vector pMSCV-sox2 which was transfected into PT67 by lipofectamine 2000 with pMIG (including green fluorescence protein) as a control. Flow cytometry analysis showed that its transfected efficiency was 68.3%. Subsequently, we established the stable cell strain by G418 selection which could produce virus. Its viral titer was up to 8.16x10(7) CFU/mL. This greatly facilitates the further study of bovine induced pluripotent stem cells induced from bovine somatic cells by defined factors.
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Evaluation of biomarkers of inflammation in response to benzalkonium chloride on corneal and conjunctival epithelial cells.
J Ocul Pharmacol Ther
PUBLISHED: 10-28-2009
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Most eye drops contain preservatives; benzalkonium chloride (BAK) is most common. Recent data demonstrated BAK adding to toxicity. BAK is degraded into hydrogen peroxide (H(2)O(2)), which in even small amounts is known to be an irritant. Increased toxicity should cause localized inflammation with increased elaboration of inflammatory biomarkers. To evaluate the inflammation BAK causes to the ocular surface, enzyme linked immunosorbant assays (ELISAs) were utilized to quantify the levels of inflammatory biomarkers in response to BAK and/or H(2)O(2).
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Analysis of inflammatory cytokines in the tears of dry eye patients.
Cornea
PUBLISHED: 09-03-2009
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To determine the levels of 8 important cytokines and 1 chemokine in tears of patients with dry eye disease.
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C3PO, an endoribonuclease that promotes RNAi by facilitating RISC activation.
Science
PUBLISHED: 08-08-2009
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The catalytic engine of RNA interference (RNAi) is the RNA-induced silencing complex (RISC), wherein the endoribonuclease Argonaute and single-stranded small interfering RNA (siRNA) direct target mRNA cleavage. We reconstituted long double-stranded RNA- and duplex siRNA-initiated RISC activities with the use of recombinant Drosophila Dicer-2, R2D2, and Ago2 proteins. We used this core reconstitution system to purify an RNAi regulator that we term C3PO (component 3 promoter of RISC), a complex of Translin and Trax. C3PO is a Mg2+-dependent endoribonuclease that promotes RISC activation by removing siRNA passenger strand cleavage products. These studies establish an in vitro RNAi reconstitution system and identify C3PO as a key activator of the core RNAi machinery.
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Metabolism of cyadox in rat, chicken and pig liver microsomes and identification of metabolites by accurate mass measurements using electrospray ionization hybrid ion trap/time-of-flight mass spectrometry.
Rapid Commun. Mass Spectrom.
PUBLISHED: 06-09-2009
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Cyadox (CYX), (2-formylquinoxaline)-N(1),N(4)-dioxide cyanoacetylhydrazone, is a growth promoter, which is more efficient and less toxic to animals. Few studies have been performed to reveal the metabolism of CYX in animals till now. In this study, the metabolic fate of CYX in the liver microsomes of animal was investigated firstly using high-performance liquid chromatography combined with hybrid ion trap/time-of-flight mass spectrometry. CYX was incubated with rat, chicken and pig liver microsomes in the presence of a NADPH-generating system. Multiple scans of metabolites in MS and MS(2) modes and accurate mass measurements were performed simultaneously through data-dependent acquisition. Most measured mass errors were less than 10 ppm for both protonated molecules and fragment ions using external mass calibration. The structures of metabolites and their fragment ions were easily and reliably characterized based on the accurate MS(2) spectra and known structure of CYX. The relative biotransformation of CYX into characterized metabolites was estimated based on the UV absorption and the assumption that all metabolites had the same extinction coefficient as the parent compound at 305 nm. Totally, seven metabolites were identified as three reduced metabolites (cyadox 1-monoxide (Cy1), cyadox 4-monoxide (Cy2) and bisdesoxycyadox (Cy4)), three hydrolysis metabolites of the amide bond (N-decyanoacetyl cyadox (Cy5), N-decyanoacetyl cyadox 1-monoxide (Cy6) and N-decyanoacetyl bisdesoxycyadox (Cy7)) and a hydroxylation metabolite of Cy1 (Cy3). Cy1-Cy6 could be detected in rat, chicken and pig liver microsomes while metabolite Cy7 could only be observed in pig. The amounts of the metabolites in three species are different. For the formations of Cy1 and Cy3, the rank order was rat approximately chicken > pig. For Cy4 and Cy5, the order was pig > rat > chicken. Cy1 and Cy4 have been previously reported, whereas the other five metabolites were novel. The N-->O group reduction and hydroxylation were the main metabolic pathways for CYX in the three species.
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Effect of BDNF Val66Met polymorphism on digital working memory and spatial localization in a healthy Chinese Han population.
J. Mol. Neurosci.
PUBLISHED: 03-03-2009
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Cognitive abilities are complex human traits influenced by genetic factors. Brain-derived neurotrophic factor (BDNF), a unique polypeptide growth factor, has an influence on the differentiation and survival of neurons in the nervous system. A single-nucleotide polymorphism (rs6265) in the human gene, resulting in a valine to methionine substitution in the pro-BDNF protein, was thought to associate with psychiatric disorders and might play roles in the individual difference of cognitive abilities. However, the specific roles of the gene in cognition remain unclear. To investigate the relationships between the substitution and cognitive abilities, a healthy population-based study and the PCR-SSCP method were performed. The results showed the substitution was associated with digital working memory (p = 0.02) and spatial localization (p = 0.03), but not with inhibition, shifting, updating, visuo-spatial working memory, long-term memory, and others (p > 0.05) among the compared genotype groups analyzed by general linear model. On the other hand, the participants with BDNF (GG) had higher average performance in digital working memory and spatial localization than the ones with BDNF (AA). The findings of the present work implied that the variation in BDNF might play positive roles in human digital working memory and spatial localization.
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sPLA2-IIa is an inflammatory mediator when the ocular surface is compromised.
Exp. Eye Res.
PUBLISHED: 01-01-2009
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sPLA2-IIa is an enzyme at high concentration in tears that has been known as an innate barrier of the ocular surface against microbial infection. sPLA2-IIa and other enzymes in the same protein family are known to hydrolyze fatty acids resulting in the generation of free arachidonic acid (AA) and lysophospholipids, which are the precursors of pro-inflammatory lipid mediators, such as PGE(2). sPLA2-IIa has been shown to be an inflammatory mediator in non-ocular inflammatory diseases such as rheumatoid arthritis (RA). It was also found to be increased in the tears of the patients with dry eye disease, chronic blepharitis and contact lens intolerance. However, the role of sPLA2-IIa in chronic ocular surface inflammation has yet to be determined. In the current study, we examined the potential role of sPLA2-IIa in inflammation of ocular surface diseases. Our results show that the activity of sPLA2-IIa was significantly increased in tears from dry eye disease patients compared with that from normal subjects. Also, sPLA2-IIa stimulated the production of PGE(2) in ocular surface epithelial cell cultures. The stimulating effect was markedly enhanced when the cells or tissues were pre-compromised with TNF-alpha, IL-1beta or desiccation. Furthermore, sPLA2-IIa stimulated inflammatory cytokine production in the ocular surface epithelial cell cultures in vitro. To our knowledge, this is the first report regarding the role of sPLA2-IIa as an inflammatory mediator in ocular surface inflammation. These findings indicate that sPLA2-IIa may play an important role in chronic ocular surface inflammation, especially when the ocular surface is compromised.
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Serum Cytosolic ?-Glucosidase Levels In Neonatal Necrotizing Enterocolitis.
Iran J Pediatr
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This study was conducted to compare serum Cytosolic ?-Glucosidase (CBG) levels of age-matched control patients with those of infants with neonatal necrotizing enterocolitis (NEC), to determine eventual association between Serum Cytosolic ?-Glucosidase levels with intensity of the disease in NEC infants.
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Transmissibility of the highly pathogenic avian influenza virus, subtype H5N1 in domestic poultry: a spatio-temporal estimation at the global scale.
Geospat Health
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The highly pathogenic avian influenza virus (HPAIV), subtype H5N1 poses a serious threat not only to the poultry industry and wild birds but also to humans. Despite a large number of studies conducted on various aspects of this virus, its transmissibility is still poorly understood. This study quantifies the basic reproductive number (R0) of the global HPAIV H5N1 spread within domestic poultry during December 2003 to December 2009. Three different approaches were applied to estimate R0 for HPAIV H5N1: (i) epidemic doubling time; (ii) spatial distance-based nearest neighbour; and (iii) spatio-temporal distance-based nearest neighbour. These three approaches represent temporal (tR0), spatial (sR0) and spatio-temporal transmissibility (stR0), respectively. The joint application of these three approaches provides a more complete profile by characterising the transmissibility traits of infectious diseases from different perspectives. Estimates of tR0 gradually decreased over the six sequential epidemic waves (EWs) examined, suggesting that the implemented control measures were effective in reducing the number of outbreaks. However, sR0 and stR0 increased from EW1, peaked in EW3 and then gradually decreased during EW4-EW6, reflecting different aspects of disease transmissibility compared to tR0. The application of all three methods in the final EW6 showed R0 >1, suggesting that the control measures implemented did not completely interrupt the transmission cycle, and hence were insufficient to eliminate HPAIV H5N1. Close monitoring of HPAIV H5N1 outbreaks and enhanced control policies is advised.
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Phylogeography of Quercus variabilis based on chloroplast DNA sequence in East Asia: multiple glacial refugia and Mainland-migrated island populations.
PLoS ONE
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The biogeographical relationships between far-separated populations, in particular, those in the mainland and islands, remain unclear for widespread species in eastern Asia where the current distribution of plants was greatly influenced by the Quaternary climate. Deciduous Oriental oak (Quercus variabilis) is one of the most widely distributed species in eastern Asia. In this study, leaf material of 528 Q. variabilis trees from 50 populations across the whole distribution (Mainland China, Korea Peninsular as well as Japan, Zhoushan and Taiwan Islands) was collected, and three cpDNA intergenic spacer fragments were sequenced using universal primers. A total of 26 haplotypes were detected, and it showed a weak phylogeographical structure in eastern Asia populations at species level, however, in the central-eastern region of Mainland China, the populations had more haplotypes than those in other regions, with a significant phylogeographical structure (N(ST=?)0.751> G(ST=?)0.690, P<0.05). Q. variabilis displayed high interpopulation and low intrapopulation genetic diversity across the distribution range. Both unimodal mismatch distribution and significant negative Fus F(S) indicated a demographic expansion of Q. variabilis populations in East Asia. A fossil calibrated phylogenetic tree showed a rapid speciation during Pleistocene, with a population augment occurred in Middle Pleistocene. Both diversity patterns and ecological niche modelling indicated there could be multiple glacial refugia and possible bottleneck or founder effects occurred in the southern Japan. We dated major spatial expansion of Q. variabilis population in eastern Asia to the last glacial cycle(s), a period with sea-level fluctuations and land bridges in East China Sea as possible dispersal corridors. This study showed that geographical heterogeneity combined with climate and sea-level changes have shaped the genetic structure of this wide-ranging tree species in East Asia.
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BMS309403 stimulates glucose uptake in myotubes through activation of AMP-activated protein kinase.
PLoS ONE
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BMS309403 is a biphenyl azole inhibitor against fatty acid binding protein 4 (FABP4) and regarded as a lead compound for effective treatment of obesity related cardio-metabolic diseases. Here we discovered an off-target activity of BMS309403 in that it stimulates glucose uptake in C2C12 myotubes in a temporal and dose dependent manner via activation of AMP-activated protein kinase (AMPK) signaling pathway but independent of FABPs. Further analysis indicated that BMS309403 activates AMPK through increasing the ratio of intracellular AMP:ATP while decreasing mitochondrial membrane potential. These findings provide mechanistic insights on the action of BMS309403.
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Simultaneous determination of 15 aminoglycoside(s) residues in animal derived foods by automated solid-phase extraction and liquid chromatography-tandem mass spectrometry.
Food Chem
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An automated method has been developed for the simultaneous quantification of 15 aminoglycosides in muscle, liver (pigs, chicken and cattle), kidney (pigs and cattle), cow milk, and hen eggs by liquid chromatography tandem mass spectrometry. Homogenized samples were extracted by monopotassium phosphate buffer (including ethylene diamine tetraacetic acid), and cleaned up with auto solid-phase extraction by carboxylic acid cartridges. The analytes were separated by a specialized column for aminoglycosides, and eluted with trifluoroacetic acid and acetonitrile. The decision limits (CC?) of apramycin, gentamycin, tobramycin, paromomycin, hygromycin, neomycin, kanamycin, sisomicin, netilmicin, ribostamycin, kasugamycin, amikacin, streptomycin, dihydrostreptomycin and spectinomycin were ranged from 8.1 to 11.8 ?g/kg and detection capabilities (CC?) from 16.4 to 21.8 ?g/kg. High correlation coefficients (r(2)>0.99) of calibration curves for the analytes were obtained within linear from 20 to 1000 ?g/kg. Reasonable recoveries (71-108%) were demonstrated with excellent relative standard deviation (RSD). This method is simple pretreatment, rapid determination and high sensitivity, which can be used in the determination of multi-aminoglycosides in complex samples.
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Development of a sensitive and robust liquid chromatography coupled with tandem mass spectrometry and a pressurized liquid extraction for the determination of aflatoxins and ochratoxin A in animal derived foods.
J Chromatogr A
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A liquid chromatography-tandem mass spectrometry (LC-MS/MS) with a pressurized liquid extraction (PLE) was developed for the simultaneous determination of aflatoxins B?, B?, G?, G?, M? and M?, and ochratoxin A in the muscle, liver, kidney and fat of swine, bovine and sheep, muscle and liver of chicken, muscle and skin of fish, as well as in hen eggs and dairy milk. Samples were extracted with PLE and cleaned-up with solid phase extraction (SPE) on HLB cartridges. The optimum extraction conditions were obtained as a 11 ml ASE cell, acetonitrile/hexane as the extraction solvent, 1500 psi, 100 °C, a 5 min static time and a 60% flush volume. A cheaper and widely used SPE column (Oasis HLB) was applied during clean up. The detection and quantification of the 7 mycotoxins were performed by a reversed-phase liquid chromatography coupled with electrospray ionization triple quadrupole mass spectrometry (LC/ESI-MS/MS). The limits of detection defined as CC? varied from 0.07 ?g/kg to 0.59 ?g/kg. The recoveries of spiked samples from 0.25 ?g/kg to 1 ?g/kg ranged from 68.3% to 105.7% with the relative standard deviations of less than 17.6%. Performances of the whole analytical procedure met the criteria established by the European Commission for mass spectrometric detection.
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Clinical and pathological spectrums of aristolochic acid nephropathy.
Clin. Nephrol.
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To study the clinical and pathological characteristics of aristolochic acid nephropathy (AAN).
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Determination of 17 macrolide antibiotics and avermectins residues in meat with accelerated solvent extraction by liquid chromatography-tandem mass spectrometry.
J. Chromatogr. B Analyt. Technol. Biomed. Life Sci.
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A method has been developed for simultaneous determination of 17 kinds of macrolide antibiotics and avermectins residues in animal origin foods. Samples were extracted with acetonitrile-methanol using accelerated solvent extraction (ASE) instrument. Parameters such as extraction temperature and pressure were investigated by a fractional factorial design (FFD) and the selected extraction (60 °C, 1500 psi for 10 min in two cycles) was most effective. High correlation coefficients (r > 0.999) of 17 macrolide antibiotics and avermectins were obtained within their respective linear ranges (2-400 ?g/kg) using roxithromycin as internal standard. The recoveries of them were above 75% at different spiked levels in various samples. Using ASE the method was featured as short extraction times, reduction use of extraction solvent, high extraction yields, with high level of automation.
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