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Find video protocols related to scientific articles indexed in Pubmed.
A Chemical Tuned Strategy to Develop Novel Irreversible EGFR-TK Inhibitors with Improved Safety and Pharmacokinetic Profiles.
J. Med. Chem.
PUBLISHED: 11-20-2014
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Gatekeeper T790M mutation in EGFR is the most prevalent factor underlying acquired resistance. Acrylamide-bearing quinazoline derivatives are powerful irreversible inhibitors for overcoming resistance. Nevertheless, concerns about the risk of non-specific covalent modification have motivated the development of novel cysteine-targeting inhibitors. In this paper, we demonstrate that fluoro-substituted olefins can be tuned to alter Michael addition reactivity. Incorporation of these olefins into the quinazoline templates produced potent EGFR inhibitors with improved safety and pharmacokinetic properties. A lead compound 5a was validated against EGFRWT, EGFR T790M as well as A431 and H1975 cancer cell lines. Additionally, compound 5a displayed a weaker inhibition against the EGFR-independent cancer cell line SW620 when compared withafatinib. Oral administration of 5a at a dose of 30mg/kg induced tumor regression in a murine-EGFRL858R/T790M driven H1975 xenograft model. Also, 5a exhibited improved oral bioavailability and safety, as well as favorable tissue distribution properties and enhanced brain uptake. These findings provide the basis of a promising strategy toward the treatment of NSCLC patients with drug resistance.
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A series of cobalt and nickel clusters based on thiol-containing ligands accompanied by in situ ligand formation.
Dalton Trans
PUBLISHED: 11-08-2014
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Eight cobalt and nickel clusters with the formulae [Co4(?4-O)(MBT)5(?2-Piv)] (), [Ni3(MBT)2()2(OCH3)2] (), [Ni4(?3-S)(?3-S2)(MBT)2()] (), [Ni4()4] (), [Ni6(?4-S)3(MBT)6]·(C2H5OH)2 (), H[Co4(?4-O)(HMBI)6]·(NO3)(TEA)0.5(CH3OH)2(H2O) (), [Ni2(HMBI)4]·(CH3OH)2 (), and [Ni5(MBI)2(HMBI)4(OCH3)2]·(CH3OH)3(H2O)2 () (HPiv = pivalic acid, H = 2-disulfanylbenzo[d]thiazole, H2 = (Z)-2-((2-mercaptophenyl)imino)benzo[d]thiazole-3(2H)-thiol, H2 = (Z)-2-(benzo[d]thiazol-2(3H)-ylideneamino)benzenethiol, TEA = triethylamine) have been solvothermally prepared via assembling distinct metal resource and thiol-containing ligands 2-mercaptobenzothiazole (HMBT)/2-mercaptobenzimidazole (H2MBI). Complexes and are tetrahedral cobalt clusters. Complex features linear arrangement of nickel ions. Complexes and are tetranuclear nickel clusters with the butterfly and square shape, respectively. Complex displays a trigonal prism geometry. Complexes and exhibit paddle-wheel and trigonal bipyramidal geometry, respectively. The starting ligand HMBT undergoes in situ ligand transformation in the formation of the nickel clusters, and the new generated inorganic ligands (S(2-) and S2(2-)) and organic ligands (H, H2 and H2) were captured within the metallic cores. Magnetic studies indicate that complexes and show dominating antiferromagnetic couplings and that spin frustration exists in .
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The Clathrin Adaptor Proteins ARH, Dab2 and Numb Play Distinct Roles in NPC1L1- versus LDL Receptor-mediated Cholesterol Uptake.
J. Biol. Chem.
PUBLISHED: 10-22-2014
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The uptake of circulating low density lipoproteins (LDL) is mediated by LDL receptor (LDLR) through clathrin-dependent endocytosis. At the early stage of this process, adaptor proteins ARH and Dab2 specifically bind the endocytic signal motif in LDLR and recruit clathrin/AP2 to initiate internalization. On the other hand, intestinal cholesterol is absorbed by Niemann-Pick C1-Like 1 (NPC1L1) through the clathrin-dependent endocytosis. Another adaptor protein Numb recognizes the endocytic motif in NPC1L1 C terminus and couples NPC1L1 to endocytic machinery. The ARH, Dab2 and Numb contain a homogeneous phosphotyrosine binding (PTB) domain that directly binds the endocytic motifs. Because ARH, Dab2 and Numb are all PTB domain family members, the emerging mystery is whether these adaptors act complementally in LDLR and NPC1L1 endocytosis. Here, we found that ARH and Dab2 did not bind NPC1L1 and were not required for NPC1L1 internalization. Similarly, Numb lacked the ability to interact with LDLR C terminus and was dispensable for LDL uptake. Only the Numb isoforms with shorter PTB domain could facilitate NPC1L1 endocytosis. Besides the reported function in intestinal cholesterol absorption, Numb also mediated cholesterol reabsorption from bile in liver. We further identified a Numb variant with G595D substitution in humans of low blood LDL-cholesterol. The G595D substitution impaired NPC1L1 internalization and cholesterol reabsorption, due to attenuating affinity of Numb to clathrin/AP2. These results demonstrate that Numb specifically regulates NPC1L1-mediated cholesterol absorption both in human intestine and liver, distinct from ARH and Dab2 those participate in LDLR-mediated LDL uptake.
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[Determination of N-methyl carbamate pesticides in diet samples by high performance liquid chromatography-linear ion trap mass spectrometry with gel permeation chromatography cleanup].
Se Pu
PUBLISHED: 09-05-2014
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A method for the determination of N-methyl carbamate (NMC) pesticides in diet samples was developed by high performance liquid chromatography-linear ion trap mass spectrometry (HPLC-LIT-MS). The samples with the isotope internal standard were ultrasonically extracted with acetonitrile saturated with cyclohexane, and then cleaned-up by passing through gel permeation chromatographic (GPC) column. The LC separation was performed on a CAPCELL PAK CR column (100 mm x 2.1 mm, 5 microm; SCX-C18 (1 : 4)) using acetonitrile and 5 mmol/L ammonium formate/0.1% (v/v) formic acid aqueous solution as mobile phases (gradient elution) at a flow rate of 0.2 mL/min. The ionization of the analytes was performed by positive electrospray mode. Selective reaction monitoring (SRM) was used for the monitoring of MS3 transitions for each compound. The internal standard was used for quantitation. The average recoveries were in the range of 60.4% - 114%, and the relative standard deviations (RSDs) were all not more than 16.2%. The limits of detection (LODs) were 0.001-0.010 mg/kg. The method was successfully applied to the determination of 15 compounds of interest in nine foodstuffs from the fourth Chinese Total Diet Study (TDS) performed in 2007, and aldicarb and carbofuran were found in several samples.
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[Determination of 18 pesticide residues in red wine by ultra high performance liquid chromatography-high resolution mass spectrometry with isotope dilution technique].
Se Pu
PUBLISHED: 09-05-2014
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A method for the simultaneous determination of 18 pesticide residues in red wine was developed using ultra high performance liquid chromatography-high resolution mass spectrometry (UPLC-HRMS) with isotope dilution technique. The red wine samples were extracted with acetonitrile, and the extracts were cleaned up with dispersive solid phase extraction (dSPE) using the mixture of N-propyl ethylene diamine (PSA) and C18 powder as sorbent. The extracted components were separated on a BEH C18 column by gradient elution. The qualitative and quantitative analyses were operated under full scan/data dependent MS/MS (ddms2) and targeted selective ion monitoring (tSIM) by high resolution mass spectrometry, respectively. Carbendazim-D4, chlorpyrifos-D10, imidacloprid-D4, methoxyfenozide-D9, pyrimethanil-D5 and tebuconazole-D6 were used as the internal standards to reduce the matrix effects. The response of each pesticide showed a good linearity in the range of 0.5-50 microg/kg with the correlation coefficient more than 0.999. The limits of detection and quantification for the 18 pesticides in the spiked blank red wine were 0.5 microg/kg and 1.0 microg/kg, respectively. The recovery results with spiked blank red wine samples at the levels of 1 to 40 microg/kg were satisfactory with average recoveries of 85.4% - 117.9% and the RSDs of 0.5%-6.1%. The method was applied for the determination of the red wine real samples from the market. Carbendazim, imidacloprid, pyrimethanil, tebuconazole and triadimenol were detected in the samples. The results show that the method is suitable for the rapid screening and quantitative analysis of pesticide residues in red wine.
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[Size distributions of water-soluble inorganic ions in atmospheric aerosols in Fukang].
Huan Jing Ke Xue
PUBLISHED: 08-28-2014
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To investigate the levels and size distributions of water soluble inorganic components, samples were collected with Andersen cascade sampler from Feb. 2011 to Feb. 2012, in Fukang, and were analyzed by IC. The variation trend, concentration level, composition, sources and size distribution of major ions during non-heating period were compared with heating period. Based on the specific samples, ionic compositions and size distributions were analyzed during heavy pollution, straw burning and spring planting periods. The results showed that inorganic components in Fukang were severely affected by heating. The total water soluble ions in fine and coarse particles during non-heating and heating periods were 11.17, 12.68 microg x m(-3) and 35.98, 22.22 microg x m(-3), respectively. SO4(2-) was mainly from saline-alkali soil, NO3(-) and NH4(+) were from resuspension of farmland soil during non-heating period, while SO4(2-), NO3(-) and NH4(+) were all from the fossil fuel consumption during the heating period. All ions were bimodal distribution during non-heating and heating periods. During the heating period, the particle size growth of SO4(2-), NO3(-) and NH4(+) in fine mode was found, SO4(2-) and NH4(+) peaked at 3.3-4.7 microm in coarse particles. Secondary pollutions were serious during heavy pollution days with high levels of secondary ions between 1.1 and 2.1 microm. Biomass burning obviously affected the size distribution of ions during the straw burning period and ions focused on smaller than 0.65 microm, while there were more soil dusts during spring planting periods and ions concentrated in larger than 3.3 microm.
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Organochlorine pesticides and pyrethroids in Chinese tea by screening and confirmatory detection using GC-NCI-MS and GC-MS/MS.
J. Agric. Food Chem.
PUBLISHED: 07-10-2014
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One hundred and one tea samples including green tea, dark tea, scented tea, black tea, and oolong tea were screened and confirmed for the contamination of 31 organochlorine pesticides (OCPs) and 19 pyrethroids (PYs) by gas chromatography-negative chemical ionization-mass spectrometry (GC-NCI-MS) and gas chromatography-tandem mass spectrometry (GC-MS/MS). 50 pesticides, 3 deuterium-labeled PYs, and 24 (13)C-labeled OCPs were separated well with the limits of detection (LODs) ranging from 0.02 to 4.5 ?g/kg for GC-NCI-MS, and the positive samples were verified by GC-MS/MS with LODs of 0.1-5.0 ?g/kg. High detection rates for some PYs, such as 63.4% for bifenthrin (not detected (ND)-3.848 mg/kg), 55.4% for ?-cyhalothrin (ND-3.244 mg/kg), 46.5% for cypermethrin (ND-0.499 mg/kg), and 24.8% for fenvalerate (ND-0.217 mg/kg), were found in the 101 tea samples. Endosulfan, DDTs, HCHs, and heptachlor, the persistent OCPs, were frequently detected with rates of 63.4% (ND-1.802 mg/kg), 56.4% (ND-0.411 mg/kg), 24.8% (ND-0.377 mg/kg), and 15.8% (ND-0.100 mg/kg), respectively.
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Large magnetocaloric effect in a dense and stable inorganic-organic hybrid cobridged by in situ generated sulfate and oxalate.
Chem Asian J
PUBLISHED: 07-07-2014
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A dense and stable inorganic-organic hybrid with distorted cubic [Gd4 O4 ] units as building blocks bridged by in situ generated sulfate and oxalate was synthesized. Magnetic measurements indicate that the title complex features a -?Sm (max) =51.49?J?kg(-1) ?K(-1) , which is among the highest values reported so far.
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Mechanisms underlying attenuation of apoptosis of cortical neurons in the hypoxic brain by flavonoids from the stems and leaves of Scutellaria baicalensis Georgi.
Neural Regen Res
PUBLISHED: 07-05-2014
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Flavonoids from the stems and leaves of Scutellaria baicalensis Georgi, an antioxidant, markedly improve memory impairments and neuronal injuries. In the present study, primary cortical neurons of rats were exposed to potassium cyanide to establish a model of in vitro neural cell apoptosis. Inhibition of apoptosis by flavonoids from the stems and leaves of Scutellaria baicalensis Georgi at concentrations of 18.98, 37.36, and 75.92 ?g/mL was detected using this model. These flavonoids dramatically increased cell survival, inhibited cell apoptosis and excessive production of malondialdehyde, and increased the activities of superoxide dismutase, glutathione peroxidase, and Na(+)-K(+)-ATPase in primary cortical neurons exposed to potassium cyanide. The flavonoids from the stems and leaves of Scutellaria baicalensis Georgi were originally found to have a polyhydric structure and to protect against cerebral hypoxia in in vitro and in vivo models, including hypoxia induced by potassium cyanide or cerebral ischemia. The present study suggests that flavonoids from the stems and leaves of Scutellaria baicalensis Georgi exert neuroprotective effects via modulation of oxidative stress, such as malondialdehyde, superoxide dismutase, glutathione peroxidase and Na(+)-K(+)-ATPase disorders induced by potassium cyanide.
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[Ocuurence of organophosphorus pesticides in animal foods and their diet exposure assessment].
Zhonghua Yu Fang Yi Xue Za Zhi
PUBLISHED: 07-03-2014
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To investigate the levels of organophosphorus pesticides (OPPs) in animal foods and to assess the diet exposure risk of OPPs to Chinese population.
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Detection of mercury(II) by DNA templated gold nanoclusters based on forming thymidine-Hg(2+) -thymidine duplexes.
Luminescence
PUBLISHED: 06-30-2014
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We have successfully synthesized gold nanoclusters (AuNCs) templated with DNA (5'-CCCCCCCCCCCCTTTTTT-3'), and subsequently employed the fluorescent DNA-AuNCs as a novel probe for sensitive detections of mercury ions (Hg(2+) ). Basically, the procedure is due to the formation of thymidine-Hg(2+) -thymidine duplexes between DNA-AuNCs and Hg(2+) , thus leading to aggregations of DNA-AuNCs described here occurring, and facilitating their fluorescence decrease. Significantly, this decrease of fluorescent signals permitted sensitive detection of Hg(2+) in a linear range of 0.1-100 µmol L(-1) , with a detection limit of 0.083 µmol L(-1) at a signal-to-noise ratio of 3. Additionally, the practicality of this probe for assaying Hg(2+) in human urine and lake water samples was further validated, and showed various advantages including simplicity, selectivity, sensitivity and low cost, demonstrating its potential to broaden ways for assaying Hg(2+) in real samples. Copyright © 2014 John Wiley & Sons, Ltd.
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Dose-response relationship between orally administered ammonium perchlorate and urine perchlorate concentrations in rats.
Arch Environ Occup Health
PUBLISHED: 06-28-2014
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Abstract To evaluate the feasibility of urine perchlorate as a biomarker of Ammonium Perchlorate (AP) exposure and and to explore the correlation between the thyroid function indicators and the perchlorate concentrations, a sensitive and selective ultra-high-performance liquid chromatography mass spectrometer (UHPLC-MS) method was developed to detect perchlorate in urine samples. Rats were orally administrated with different doses of perchlorate. Serum free-thyroxine (FT4), free-triiodothyronine (FT3), and thyroid stimulating hormone (TSH) were determined by radioimmunoassays. The results showed that a dose of AP up to 520 mg kg(-1) b. wt. induced a significant increase of thyroid stimulating hormone (TSH), with a decrease of free thyroxine (FT4). Particularly, the levels of urine perchlorate increased dose-dependently on AP exposure from drinking water. The findings highlighted that urine perchlorate may be a useful biomarker for AP environmental exposure.
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Proton-Transfer Polymerization (HTP): Converting Methacrylates to Polyesters by an N-Heterocyclic Carbene.
Angew. Chem. Int. Ed. Engl.
PUBLISHED: 06-27-2014
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A new polymerization termed proton (H)-transfer polymerization (HTP) has been developed to convert dimethacrylates to unsaturated polyesters. HTP is catalyzed by a selective N-heterocyclic carbene capable of promoting intermolecular Umpolung condensation through proton transfer and proceeds through the step-growth propagation cycles via enamine intermediates. The role of the added suitable phenol, which is critical for achieving an effective HTP, is twofold: shutting down the radically induced chain-growth addition polymerization under HTP conditions (typically at 80-120?°C) and facilitating proton transfer after each monomer enchainment. The resulting unsaturated polyesters have a high thermal stability and can be readily cross-linked to robust polyester materials.
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[Determination of fatty acid esters of chloropropanediols in diet samples by gas chromatography-mass spectrometry coupled with solid-supported liquid-liquid extraction].
Wei Sheng Yan Jiu
PUBLISHED: 06-27-2014
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To establish a method for the determination of fatty acid esters of 3-monochloropropane-1, 2-diol (3-MCPD) and 2-monochloropropane-1, 3-diol (2-MCPD) in diet samples by gas chromatography-mass spectrometry (GC-MS) with solid-supported liquid-liquid extraction (SLE).
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Application of gas chromatography-mass spectrometry in analyzing pharmacokinetics and distribution of deltamethrin in miniature pig tissues.
Biomed. Environ. Sci.
PUBLISHED: 06-26-2014
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To characterize the pharmacokinetics and distribution profiles of deltamethrin in miniature pig tissues by gas chromatography-mass spectrometry (GC-MS).
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Dexmedetomidine renders a brain protection on hippocampal formation through inhibition of nNOS-NO signalling in endotoxin-induced shock rats.
Brain Inj
PUBLISHED: 04-30-2014
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Endotoxin shock (ES) and its severe complications, such as brain injury, remain a handicap clinically. Therefore, it is a clinical significance of developing a new drug to treat brain damage induced by ES.
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Reversal of tumor growth by gene modification of mesenchymal stem cells using spermine-pullulan/DNA nanoparticles.
J Biomed Nanotechnol
PUBLISHED: 04-18-2014
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Mesenchymal stem cells (MSCs) are a promising tool for delivering of therapeutic agents in cancer treatment. In the present study, our findings suggested that both i.v. and intratumoral injection of MSCs could favor tumor growth under physiologic conditions. However, the anti-tumor effects of MSC-IL-12 were achieved using our strategy. Unlike the previously reported method, the genetic engineering of MSCs was conducted by non-viral transfection using the new vector, spermine-pullulan. The transfection, cytotoxicity, and the cellular internalization of this vector were evaluated. Then, the therapeutical gene, IL-12, was delivered to the MSCs using this vector. The in vitro secretions of IL-12 by MSC-IL-12 confirmed the success of using spermine-pullulan/DNA nanoparticles for the gene transfection. We used the MSC-IL-12 for the in vivo treatment of both B16F10 metastasis tumor and the established subcutaneous B16BL6 tumor. For the B16F10 metastasis tumor, treatment with MSC-IL-12 significantly reduced lung metastases. For the established subcutaneous B16BL6 tumor, intratumoral injected MSC-IL-12 cells considerably retarded tumor growth. Prolonged survival was observed when MSC-IL-12 cells were injected through the tail vein or intratumorally, indicating that the MSCs engineered with the therapeutic gene could reverse the tumor-promoting effects of MSCs using the nonviral transduction method. However, the intravenous injected MSC-IL-12 did not prevent the tumor growth of the established subcutaneous B16BL6 tumor. Thus, we examined the the in vivo distribution of MSCs in different organs and it was found that MSCs were mainly distributed in the lungs, which may explain the inability of intravenously injected MSC-IL-12 to inhibit the growth of the established subcutaneous tumor.
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Comparison of short-term efficacy and safety of TIROX and DCF regimens for advanced gastric cancer.
J. Int. Med. Res.
PUBLISHED: 04-09-2014
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To compare the short-term efficacy and safety profile of the S-1?+?irinotecan?+?oxaliplatin (TIROX) and docetaxel?+?cisplatin?+?flurouracil (DCF) anticancer regimens in patients with advanced gastric cancer.
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A novel species of ellipsoidal multicellular magnetotactic prokaryotes from Lake Yuehu in China.
Environ. Microbiol.
PUBLISHED: 04-04-2014
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Two morphotypes of multicellular magnetotactic prokaryotes (MMPs) have been identified: spherical (several species) and ellipsoidal (previously one species). Here, we report novel ellipsoidal MMPs that are ??10?×?8??m in size, and composed of about 86 cells arranged in six to eight interlaced circles. Each MMP was composed of cells that synthesized either bullet-shaped magnetite magnetosomes alone, or both bullet-shaped magnetite and rectangular greigite magnetosomes. They showed north-seeking magnetotaxis, ping-pong motility and negative phototaxis at a velocity up to 300??m?s(-1) . During reproduction, they divided along either their long- or short-body axes. For genetic analysis, we sorted the ellipsoidal MMPs with micromanipulation and amplified their genomes using multiple displacement amplification. We sequenced the 16S rRNA gene and found 6.9% sequence divergence from that of ellipsoidal MMPs, Candidatus Magnetananas tsingtaoensis and >?8.3% divergence from those of spherical MMPs. Therefore, the novel MMPs belong to different species and genus compared with the currently known ellipsoidal and spherical MMPs respectively. The novel MMPs display a morphological cell differentiation, implying a potential division of labour. These findings provide new insights into the diversity of MMPs in general, and contribute to our understanding of the evolution of multicellularity among prokaryotes.
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MCL-1 degradation mediated by JNK activation via MEKK1/TAK1-MKK4 contributes to anticancer activity of new tubulin inhibitor MT189.
Mol. Cancer Ther.
PUBLISHED: 03-31-2014
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Colchicine site-targeted tubulin inhibitors are a promising type of anticancer drugs. MT189 is a new derivative of MT119, a previously reported colchicine site-binding antitubulin agent. In this study, MT189 was demonstrated to retain the property of MT119 in disrupting microtubulin via binding to the colchicine site, causing mitotic arrest and inducing apoptosis, and to display 8.7-fold enhanced proliferative inhibition in a panel of cancer cells. MT189 was shown to elicit in vivo anticancer effects on MDA-MB-231 xenografts in nude mice, and the tumor growth was suppressed by 35.9% over 14 days. MT189 led to degradation of MCL-1, a member of the antiapoptotic BCL-2 protein family. Its overexpression reduced but its silenced expression increased the apoptotic induction followed by the treatment with MT189. Moreover, the treatment with MT189 caused activation of the MEKK1/TAK1-MKK4-JNK signaling pathway. The activated JNK resulted in phosphorylation of MCL-1, which facilitated its ubiquitination-mediated degradation. Our results show that MT189 inhibits microtubulin polymerization by binding to the colchicine site. Relief of apoptotic suppression by MCL-1 degradation together with mitotic arrest contributes to the anticancer activity of MT189.
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Change of iodine load and thyroid homeostasis induced by ammonium perchlorate in rats.
J. Huazhong Univ. Sci. Technol. Med. Sci.
PUBLISHED: 03-10-2014
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Ammonium perchlorate (AP), mainly used as solid propellants, was reported to interfere with homeostasis via competitive inhibition of iodide uptake. However, detailed mechanisms remain to be elucidated. In this study, AP was administered at 0, 130, 260 and 520 mg/kg every day to 24 male SD rats for 13 weeks. The concentrations of iodine in urine, serum thyroid hormones levels, total iodine, relative iodine and total protein, and malondialdehyde (MDA), superoxide dismutase (SOD) and catalase (CAT) activity in thyroid tissues were measured, respectively. Our results showed that high-dose perchlorate induced a significant increase in urinary iodine and serum thyroid stimulating hormone (TSH), with a decrease of total iodine and relative iodine content. Meanwhile, free thyroxine (FT4) was decreased and CAT activity was remarkably increased. Particularly, the CAT activity was increased in a dose-dependent manner. These results suggested that CAT might be enhanced to promote the synthesis of iodine, resulting in elevated urinary iodine level. Furthermore, these findings suggested that iodine in the urine and CAT activity in the thyroid might be used as biomarkers for exposure to AP, associated with thyroid hormone indicators such as TSH, FT4.
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[Determination of ethyl carbamate in wine by HPLC-FLD].
Wei Sheng Yan Jiu
PUBLISHED: 02-26-2014
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To evaluate the method for determining ethyl carbamate (EC) in wine by HPLC-FLD.
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Natural product-based design, synthesis and biological evaluation of anthra[2,1-d]thiazole-6,11-dione derivatives from rhein as novel antitumour agents.
Eur J Med Chem
PUBLISHED: 01-23-2014
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Two series of novel 2-substituted 5,7-dihydroxyanthra[2,1-d]thiazole-6,11-dione derivatives from natural rhein were designed, synthesized and evaluated for their antitumour activities against human cancer cell lines A549 and HeLa in vitro.
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Characterization and phylogenetic identification of a species of spherical multicellular magnetotactic prokaryotes that produces both magnetite and greigite crystals.
Res. Microbiol.
PUBLISHED: 01-16-2014
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Magnetotactic bacteria (MTB) are a group of Gram-negative bacteria synthesizing magnetic crystals that allow them aligning along magnetic field lines. They have diverse morphologies including cocci, rods, vibrio, spirilla, and multicellular magnetotactic prokaryotes (MMPs). MMPs are composed of 10-57 cells with peritrichous flagella on their outer surfaces and swim as an entire unit. Here, we describe a species of spherical MMPs isolated from intertidal sediments of Lake Yuehu (Yellow Sea, China). They were mainly found in the subsurface layer of gray-black sediments. Microscopy revealed that these spherical MMPs were 5.6 ± 0.9 ?m in diameter and composed of approximately 16-32 ovoid cells with a helical arrangement and peritrichous flagellation. High-resolution transmission electron microscopy showed that the MMPs contained both bullet-shaped magnetite and irregular greigite magnetosomes that were arranged in chains or clusters. These MMPs displayed typical escape motility and negative phototaxis. The 16S rRNA genes of micromanipulation-purified spherical MMPs were cloned and sequenced. Phylogenetic analysis revealed that the MMP species was affiliated with Deltaproteobacteria and displayed >2.8% sequence divergence with respect to previously reported MMPs. This is the first phylogenetic identification of a spherical MMP that produces both magnetite and greigite magnetosomes.
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Expression of the tissue inhibitor of metalloproteinase-3 by transplanted VSMCs modifies heart structure and function after myocardial infarction.
Transpl. Immunol.
PUBLISHED: 01-02-2014
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Extracellular matrix (ECM) remodelling is a critical aspect of cardiac remodelling following myocardial infarction. Tissue inhibitors of metalloproteinases (TIMPs) are physiological inhibitors of matrix metalloproteinases (MMPs) that degrade the ECM proteins. TIMP-3 is highly expressed in the heart and is markedly downregulated in patients with ischaemic cardiomyopathy. Cell-based gene therapy can enhance the effects of cell transplantation by temporally and spatially regulating the release of the gene product. The purpose of this study was to investigate the role of TIMP-3 gene-transfected vascular smooth muscle cells (VSMCs) in modifying heart structure and function in rats when transplanted 3days after myocardial infarction (MI).
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Current clinical evidence on the effect of general anesthesia on neurodevelopment in children: an updated systematic review with meta-regression.
PLoS ONE
PUBLISHED: 01-01-2014
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Several epidemiological studies have been conducted to address the later effect of anesthesia on neurodevelopment in children. However, the results are still inconclusive.
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[Determination of 30 organochlorine pesticides in animal-originated food products using combined purification by gel permeation chromatography and solid-phase extraction coupled with gas chromatography-mass spectrometry].
Se Pu
PUBLISHED: 12-28-2013
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A new analytical method was developed for the determination of 30 organochlorine pesticides (OCPs) in animal-originated food, including pork, chicken, fish and shrimp. The combined purification by gel permeation chromatography (GPC) and solid-phase extraction (SPE) were established by optimizing different fraction collection times. The detection conditions can be achieved by gas chromatography-mass spectrometry (GC-MS) using selective ion monitoring (SIM). Isotopic internal standards were used for the quantitative determination of the 30 OCPs. The sample pretreatment procedure was based on acetonitrile extraction and combined purification of GPC and Florisil SPE cartridge. The experimental results showed that the linear ranges for 30 OCPs were 5.0 - 500.0 microg/L, the correlation coefficients were better than 0.996, and the method detection limits (MDLs) of the 30 OCPs were 0.2 - 2.7 microg/kg. The spiked recoveries at three levels of 5.0, 10.0 and 20.0 microg/kg using pork, chicken, fish and shrimp samples as blank matrices were in the range of 55.0% - 119.1%, the relative standard deviations (RSDs) were in the range of 0.4% - 15.0%. The method has the advantages of wide linear range, high sensitivity and efficient clean-up procedure, and consistent with the demand of pesticide routine analysis.
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[Characteristic comparative study of particulate matters in Beijing before and during the Olympics].
Huan Jing Ke Xue
PUBLISHED: 09-14-2013
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Two city ecosystem research stations were selected for continuous monitoring of atmospheric fine particulate matter (PM2.5) concentration from June to September 2008, when the Beijing Olympic Games was held. The relationship between meteorological factors, artificial control management measures and PM2.5 dynamic characteristics were analyzed. The results showed that the daily average concentration of PM2.5 at RCEES Station, which is near the 5th North Ring, was 0.067 mg x m(-3) during the study period, and the particle concentration during the Olympic Games was 0.060 mg x m(-3), which was decreased by about 26% compared with the content before the Olympic Games (0.081 mg x m(-3)). As for JX Station located in the 2th South Ring, its daily average concentration of PM2.5 was 0.078 mg x m(-3). Similar to RCEES Station, PM2.5 average content during the Olympic Games (0.069 mg x m(-3)) was 27% lower compared with the content before the Olympic Games (0.095 mg x m(-3)). Two peaks could be found when daily distribution of PM2.5 was displayed, one appeared between 08:00 and 10:00 (the average content for RCEES and JX were 0.068 and 0.089 mg x m(-3), respectively), and the other appeared at 20:00-22:00, which could be attributed to traffic emission and road dust pollution, especially the emission from the growing number of cars in rush hours. Meteorological condition during the whole period was typical in summer in Beijing with both high temperature and humidity. Correlation analysis revealed that the concentrations of PM2.5 had a positive correlation with the air temperature (P < 0.01), while it had no significant relationship with wind speed, relative humidity or precipitation (P > 0.05). Our monitoring results suggested that the artificial air pollution control strategies were effective measures for air pollution control during 2008 Beijing Olympic Game.
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Recognition and control of the progression of age-related hearing loss.
Rejuvenation Res
PUBLISHED: 08-07-2013
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Abstract Recent breakthroughs have provided notable insights into both the pathogenesis and therapeutic strategies for age-related hearing loss (ARHL). Simultaneously, these breakthroughs enhance our knowledge about this neurodegenerative disease and raise the question of whether the disorder is preventable or even treatable. Discoveries relating to ARHL have revealed a unique link between ARHL and the underlying pathologies. Therefore, we need to better understand the pathogenesis or the mechanism of ARHL and learn how to take full advantage of various therapeutic strategies to prevent the progression of ARHL.
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Multi-drug-resistant cells enriched from chronic myeloid leukemia cells by Doxorubicin possess tumor-initiating-cell properties.
J. Pharmacol. Sci.
PUBLISHED: 08-01-2013
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Multiple drug resistance (MDR) occurring during chemotherapy is a major obstacle for treatment of cancers using chemotherapeutic drugs; thus, the mechanisms underlying MDR have attracted intensive attention. Many studies have shown that tumor-initiating cells exhibit a chemotherapeutic tolerance characteristic. However, whether the MDR cells possess tumor-initiating cells properties and its underlying mechanisms remain to be fully elucidated. In this study, we utilized a well-established MDR cell line K562/A02 enriched by doxorubicin from K562 cells to determine if the K562/A02 cells possess tumor-initiating properties and investigated its potential molecular mechanisms. We observed that the expressions of Oct4, Sox2, and Nanog, all of which are well-characterized stem cell markers, in K562/A02 cells were elevated in comparison to parental K562 cells; in addition, we found that K562/A02 cells exhibited more potent in vitro and in vivo tumor-initiating properties, as revealed by sphere assay, self-renewal assay, soft agar assay, and animal studies. Furthermore, our data suggest that snail and twist1, two well known transcriptional factors for the epithelial-mesenchymal transition (EMT) program, may be potentially involved in the acquisition of tumor-initiating properties of K562/A02 cells. Thus, our study demonstrates that MDR K562/A02 cells possess tumor-initiating properties, most likely due to the elevated expressions of snail and twist1.
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Community composition of nirS-type denitrifier in a shallow eutrophic lake.
Microb. Ecol.
PUBLISHED: 07-08-2013
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Denitrification is a major biological process to reduce nitrate to molecular nitrogen (N2). In shallow eutrophic lakes, this process can remove the largest portion of fixed nitrogen and plays an important role in self-purification of this ecosystem. To understand the structure of denitrifying communities in a shallow eutrophic lake, denitrifier communities in four sub-lakes of East Lake in Wuhan, China, were explored by restriction fragment length polymorphisms (RFLP) analysis and sequencing of nirS gene clone libraries. nirS is a functional marker gene for denitrification encoding cytochrome cd 1-containing nitrite reductase, which catalyzes the reduction of nitrite to nitric oxide. Both RFLP fingerprints clustering analysis and phylogeny analysis based on the amino acid sequences of NirS revealed that NirS-type communities in East Lake sediment could be roughly divided into three clusters. Cluster I accounted for 74-82 % of clones from the moderately eutrophic sub-lakes Tuan, Tang Ling, and Guo Zheng. Cluster II accounted for 76 % of the communities in hypertrophic sub-lake Miao Lake and cluster III as a minor group (7 % of the total), mainly presented in Miao Lake. Phylogenetic analysis revealed that cluster I was related to the reference clones from a broad range of ecological environments, and clusters II and III were more phylogenetically related to the reference clones from entrophic environments. Canonical correspondence analysis indicated that total nitrogen, total phosphate, total organic carbon, and NH4-N and NO2-N were important environmental factors affecting the dispersion of NirS-type denitrifier in the sediments. Cluster I showed a weak relationship with the nutrient content, while cluster II and III were positively related with the nutrient content. Principal coordinates analysis indicated that NirS-type communities from Tuan Lake, Tang Ling Lake, and Guo Zheng Lake sediments were divergent from those found in river, estuary sediment, and forest soil but similar to communities in constructed wetland sediment despite large geographic distances. The communities from the hypertrophic sub-lake Miao Lake deviated from other sub-lakes and the reference communities and clustered independently. Our results support the argument that environmental factors regulate the composition and distribution of the functional bacterial groups.
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Cyclooxygenase-2 genetic polymorphism and stroke subtypes in Chinese.
J. Mol. Neurosci.
PUBLISHED: 06-30-2013
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Cyclooxygenase-2 (COX-2) catalyzes the formation of prostaglandins that contribute to the inflammation in atherosclerosis. The aim of the present study was to investigate the relationship between two polymorphisms (-1195G>A and -765G>C) in the COX-2 gene and subtypes of ischemic stroke in a Chinese population.
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[Study on mechanism of thyroid cytotoxicity of ammonium perchlorate].
Zhonghua Lao Dong Wei Sheng Zhi Ye Bing Za Zhi
PUBLISHED: 06-28-2013
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To investigate the mechanism of thyroid cytotoxicity mechanism of ammonium perchlorate (AP).
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[Water-soluble inorganic salts in ambient aerosol particles in Tangshan].
Huan Jing Ke Xue
PUBLISHED: 06-27-2013
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To investigate the levels, seasonal variation and size distributions of water soluble inorganic components, samples were collected with an Andersen cascade sampler in Tangshan from Sep. 2010 to Aug. 2011, and were analyzed by IC. The results showed that the secondary inorganic components (SO4(2-), NO3(-) and NH4(+)) were the major contributors to PM9 and PM2.1, accounting for 68% and 77% of the total water soluble salts in PM9 and PM2.1, respectively. The total concentrations of these three ions in spring, summer, autumn, and winter were 35.0, 84.7, 67.3 and 61.6 microg x m(-3) in PM9, and 23.2, 64.8, 52.7 and 49.6 microg x m(-3) in PM2.1. About 70%, 75% and 94% of SO4(2-), NO3(-) and NH4(+) were found in the fine mode of aerosol, respectively. Ca2+ and Mg2+ were unimodal and mostly concentrated in the coarse mode. Those results indicated that the pollution caused by atmospheric particles is serious in Tangshan. It is urgent to control the anthropogenic emissions sources, such as vehicle emission, coal and biomass burning. Meanwhile, it is necessary to strengthen the greening and reinforce the management of the road construction.
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[Role of MEK1/ERK1, 2 pathways in the calcium-sensing receptor mediation of hypoxia-induced proliferation of rat pulmonary artery smooth muscle cells].
Zhonghua Yi Xue Za Zhi
PUBLISHED: 05-14-2013
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To explore the cell signal transduction pathway of calcium-sensing receptor (CaSR) mediated hypoxia-induced proliferation of rat pulmonary artery smooth muscle cells (PASMCs).
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Cyclooxygenase 2 genetic polymorphism may increase the risk of developing leukoaraiosis in Chinese.
J. Mol. Neurosci.
PUBLISHED: 05-13-2013
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Cyclooxygenase-2 (COX-2) is a key enzyme involved in the conversion of arachidonic acid into prostaglandins, which are important mediators of inflammation. To clarify the role of inflammation in the pathogenesis of cerebral small vessel disease (SVD), we investigate the possible modulating effect of the functional COX-2 polymorphisms -1195G > A (rs689466) and -765G > C (rs20417) on the risk for development of cerebral SVD in a Chinese population. Genomic DNA of 116 patients with lacunar infarction (LI), 334 patients with leukoaraiosis (LA) and 450 control subjects was genotyped for the COX-2 -1195G > A and -765G > C polymorphisms using polymerase chain reaction-restriction fragment length polymorphism. Distribution of genotypes and haplotypes in patients and controls were compared. The genotype distribution of the -765G > C polymorphism was not different between the patients with LI or LA and the control group. The 1195A allele carriers was identified independently to be related with LA (adjusted OR = 1.41, 95 % confidence interval (CI) = 1.09-2.10, P = 0.03) but not associated with LI. The linkage disequilibrium analysis showed that -1195G > A and -765G > C SNPs are moderate linkage disequilibrium in this study population (D = 0.70, r(2) = 0.16). Compared with G-1195-G-765 haplotype, the haplotype of A-1195-G-765 showed significantly increased the risk of LA (OR = 1.24, 95 % CI = 1.10-1.55, P = 0.04) but not LI. In conclusion, we found that -1195G > A polymorphism and A-1195-G-765 haplotype of COX-2 were associated with susceptibility to LA in a Chinese population.
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Simultaneous determination of 19 triazine pesticides and degradation products in processed cereal samples from Chinese total diet study by isotope dilution-high performance liquid chromatography-linear ion trap mass spectrometry.
Anal. Chim. Acta
PUBLISHED: 04-04-2013
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A selective and sensitive isotope dilution-high performance liquid chromatography-linear ion trap mass spectrometry (Isotope Dilution-HPLC-LIT-MS(3)) method was developed for the simultaneous determination of 19 triazine pesticides and their degradation products in processed cereal samples from Chinese total diet study (TDS). The method integrated the addition of isotope internal standards, liquid-liquid extraction (LLE), clean-up with MCX solid-phase extraction (SPE) cartridges and HPLC-LIT-MS(3) analysis with selected reaction monitoring (SRM) mode. Matrix-matched calibration curves showed good linearity (R(2)?0.9940) verified by applying the Mandels fitting test (p>0.087) performed at the 95% confidence level. Decision limits (CC?s) and detection capabilities (CC?s) of the 19 triazine pesticides and their degradation products fell in the ranges of 0.0020-0.4200 ?g kg(-1) and 0.0024-0.4500 ?g kg(-1), respectively. Recoveries ranged from 70.1% to 112.8%, with the relative standard deviations (RSDs) ranging from 1.5% to 13.5%. Furthermore, the proposed method was applied to analyzing the proposed cereal samples from the fourth Chinese TDS. Eleven triazines were detected in six cereal samples with the concentrations ranging from 0.013 to 0.987 ?g kg(-1). This method can also be used for the further determination of the triazines in other food group composites, and ultimately served as a methodological foundation for assessing the triazines in the average Chinese diet in the general population.
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Molecular characterization and expression analysis of S1 self-incompatibility locus-linked pollen 3.15 gene in Citrus reticulata.
J Integr Plant Biol
PUBLISHED: 04-03-2013
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Gametophytic self-incompatibility (GSI) is controlled by a highly polymorphic locus called the S-locus, which is an important factor that can result in seedless fruit in Citrus. The S1 self-incompatibility locus-linked pollen 3.15 gene (S1-3.15 ) belongs to a type of S locus gene. The role of S1-3.15 in the SI reaction of Citrus has not yet been reported. In this study, full-length sequences of cDNA and DNA encoding the S1-3.15 gene, referred to as CrS1-3.15 , were isolated from Wuzishatangju (Self-incompatibility, SI) and Shatangju (Self-compatibility, SC). The predicted amino acid sequences of CrS1-3.15 between Wuzishatangju and Shatangju differ by only three amino acids. Compared to Wuzishatangju, three bases were substituted in the genomic DNA of CrS1-3.15 from Shatangju. Southern blot results showed that one copy of CrS1-3.15 existed in the genomic DNA of both Wuzishatangju and Shatangju. The expression level of the CrS1-3.15 gene in the ovaries of Shatangju was approximately 60-fold higher than that in the ovaries of Wuzishatangju. When Wuzishatangju was cross-pollinated, the expression of CrS1-3.15 was upregulated in the ovaries at 3 d, and the highest expression levels were detected in the ovaries at 6 d after cross-pollination of Wuzishatangju × Shatangju. To obtain the CrS1-3.15 protein, the full-length cDNA of CrS1-3.15 genes from Wuzishatangju and Shatangju was successfully expressed in Pichia pastoris. Pollen germination frequency of Wuzishatangju was inhibited significantly with increasing CrS1-3.15 protein concentrations from SI Wuzishatangju.
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Design, synthesis, and biological evaluation of a series of benzo[de][1,7]naphthyridin-7(8H)-ones bearing a functionalized longer chain appendage as novel PARP1 inhibitors.
J. Med. Chem.
PUBLISHED: 03-21-2013
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A series of benzo[de][1,7]naphthyridin-7(8H)-ones possessing a functionalized long-chain appendage have been designed and evaluated as novel PARP1 inhibitors. The initial effort led to the first-generation PARP1 inhibitor 26 bearing a terminal phthalazin-1(2H)-one framework and showing remarkably high PARP1 inhibitory activity (0.31 nM) but only moderate potency in the cell. Further effort generated the second-generation lead 41, showing high potency against both the PARP1 enzyme and BRCA-deficient cells, especially for the BRCA1-deficient MDA-MB-436 cells (CC50 < 0.26 nM). Mechanistic studies revealed that the new PARP1 inhibitors significantly inhibited H2O2-triggered PARylation in SKOV3 cells, induced cellular accumulation of DNA double-strand breaks, and impaired cell-cycle progression in BRCA2-deficient cells. Significant potentiation on the cytotoxicity of Temozolomide was also observed. The unique structural character and exceptionally high potency of 41 made it stand out as a promising drug candidate worthy for further evaluation.
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Study of DNA interactions with bifenthrin by spectroscopic techniques and molecular modeling.
Spectrochim Acta A Mol Biomol Spectrosc
PUBLISHED: 03-17-2013
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The interaction between bifenthrin (BF) and calf thymus DNA (ctDNA) in physiological buffer (pH 7.4) was investigated by UV-vis absorption, fluorescence, circular dichroism (CD), and Fourier transform infrared (FT-IR) spectroscopy, coupled with viscosity measurements and molecular docking techniques. It was found that BF molecular could intercalate into the base pairs of ctDNA as evidenced by significant increases in absorption intensity, fluorescence polarization and relative viscosity of ctDNA, decrease in iodide quenching effect, and induced CD spectral changes. The association constant of BF with ctDNA was evaluated to be in the order of 10(4) L mol(-1). Thermodynamic analysis of the binding data obtained at different temperatures suggested that the binding process was primarily driven by hydrogen bonds and van der Waals forces, as the values of the enthalpy change (?H) and the entropy change (?S) were calculated to be -31.13±1.89 kJ mol(-1) and -22.79±1.21 J mol(-1) K(-1), respectively. The results of FT-IR spectra and molecular docking showed that a specific binding mainly existed between BF and adenine and guanine bases.
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Community composition and cellulase activity of cellulolytic bacteria from forest soils planted with broad-leaved deciduous and evergreen trees.
Appl. Microbiol. Biotechnol.
PUBLISHED: 03-09-2013
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Cellulolytic bacteria in forest soil provide carbon sources to improve the soil fertility and sustain the nutrient balance of the forest ecological system through the decomposition of cellulosic remains. These bacteria can also be utilized for the biological conversion of biomass into renewable biofuels. In this study, the community compositions and activities of cellulolytic bacteria in the soils of forests planted with broad-leaved deciduous (Chang Qing Garden, CQG) and broad-leaved evergreen (Forest Park, FP) trees in Wuhan, China were resolved through restriction fragment length polymorphism (RFLP) and sequencing analysis of the 16S rRNA gene. All of the isolates exhibited 35 RFLP fingerprint patterns and were clustered into six groups at a similarity level of 50 %. The phylogeny analysis based on the 16S rRNA gene sequence revealed that these RFLP groups could be clustered into three phylogenetic groups and further divided into six subgroups at a higher resolution. Group I consists of isolates from Bacillus cereus, Bacillus subtilis complex (I-A) and from Paenibacillus amylolyticus-related complex (I-B) and exhibited the highest cellulase activity among all of the cellulolytic bacteria isolates. Cluster II consists of isolates belonging to Microbacterium testaceum (II-A), Chryseobacterium indoltheticum (II-B), and Flavobacterium pectinovorum and the related complex (II-C). Cluster III consists of isolates belonging to Pseudomonas putida-related species. The community shift with respect to the plant species and the soil properties was evidenced by the phylogenetic composition of the communities. Groups I-A and I-B, which account for 36.0 % of the cellulolytic communities in the CQG site, are the dominant groups (88.4 %) in the FP site. Alternatively, the ratio of the bacteria belonging to group III (P. putida-related isolates) shifted from 28.0 % in CQG to 4.0 % in FP. The soil nutrient analysis revealed that the CQG site planted with deciduous broad-leaved trees has a richer organic nutrient (total organic carbon and total nitrogen) than the FP site planted with evergreen broad-leaved trees. Against this background, the population density and the diversity of cellulolytic bacteria in the CQG site are clearly higher than those in the FP site, and the latter was dominated with high-cellulase-activity Bacillus- and Paenibacillus-related bacteria. The canonical correspondence analysis further indicated that the distribution of these groups is correlated with the FP site, whereas groups II and III are correlated with the organic nutrient-rich CQG site.
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Simultaneous determination of total fatty acid esters of chloropropanols in edible oils by gas chromatography-mass spectrometry with solid-supported liquid-liquid extraction.
J Chromatogr A
PUBLISHED: 03-05-2013
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This study aimed to establish a novel robust method for the simultaneous determination of total fatty acid esters of 4 chloropropanols including fatty acid esters of 3-monochloropropane-1,2-diol (3-MCPD esters), 2-monochloropropane-1,3-diol (2-MCPD esters), 1,3-dichloropropan-2-ol (1,3-DCP esters) and 2,3-dichloropropan-1-ol (2,3-DCP esters) in edible oils. In this method, sodium methylate in methanol was used as the reagent for the ester cleavage reaction of chloropropanols esters. The reaction products were extracted by a sodium sulfate solution, and then purified by solid-supported liquid-liquid extraction (SLE) using diatomaceous earth (Hydromatrix™) as the sorbent. Finally, the extracts were derivatized with heptafluorobutyrylim idazole (HFBI) and analyzed by gas chromatography-mass spectrometry (GC-MS). Quantification was achieved using deuterated chloropropanols as their respective internal standards, including 3-MCPD-d5, 2-MCPD-d5, 1,3-DCP-d5 and 2,3-DCP-d5. A good linear relationship between peak area and concentrations was obtained within the range of 0.025-2.000mgL(-1) with a correlation coefficients not less than 0.999 for all the chloropropanols esters. The limits of detection (LODs) of esters of 3-MCPD, 2-MCPD, 1,3-DCP and 2,3-DCP (calculated as corresponding chloropropanols) were 30, 30, 100 and 30?gkg(-1), respectively. The average recoveries of the 3-MCPD esters and the 4 chloropropanols spiked at 0.1, 0.5 and 2mgkg(-1) into blank oil matrix were typically in a range from 70.7% to 113.3%. The robust method validation data including calibration, LOD/LOQ, accuracy and repeatability and proficiency test results (Z-score: -0.5) of the official Food Analysis Performance Assessment Scheme (FAPAS) indicated that the present quantitative method could be successfully applied to the determination of total chloropropanols esters in various edible oils.
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Design and synthesis of pyrido[3,2-?]carbazole derivatives and their analogues as potent antitumour agents.
Eur J Med Chem
PUBLISHED: 03-05-2013
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A series of pyrido[3,2-?]carbazole derivatives and their analogues have been prepared and evaluated for their antitumour activity against human lung cancer A549 cells and colon cancer HT29 cells. The intermediates 4a-4k are successfully synthesized from 1a-1k and ethyl 2-(3-bromopyridin-2-yl)acetate by Knoevenagel condensation and intramolecular Heck-type reaction, and this is a novel and efficient synthetic approach to the core scaffold of the target compounds. These target compounds have shown an interesting antitumour profile towards the tested cell lines with IC50 values ranging from 0.07 ?M to 4.45 ?M. Among all the compounds synthesized, 8 compounds show higher potency than R16, 12 compounds are as potent as R16, and 6 compounds are less potent than R16. The best compound 24 is 7 times and approximately 10 times as potent as R16 against A549 and HT29 cells, respectively.
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Novel rod-shaped magnetotactic bacteria belonging to the class Alphaproteobacteria.
Appl. Environ. Microbiol.
PUBLISHED: 03-01-2013
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Novel large, rod-shaped magnetotactic bacteria (MTB) were discovered in intertidal sediments of the Yellow Sea, China. They biomineralized more than 300 rectangular magnetite magnetosomes per cell. Phylogenetic analysis based on the 16S rRNA gene sequence revealed that they are affiliated with the Alphaproteobacteria and may represent a new genus of MTB.
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Marine-derived angiogenesis inhibitors for cancer therapy.
Mar Drugs
PUBLISHED: 02-04-2013
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Angiogenesis inhibitors have been successfully used for cancer therapy in the clinic. Many marine-derived natural products and their analogues have been reported to show antiangiogenic activities. Compared with the drugs in the clinic, these agents display interesting characteristics, including diverse sources, unique chemical structures, special modes of action, and distinct activity and toxicity profiles. This review will first provide an overview of the current marine-derived angiogenesis inhibitors based on their primary targets and/or mechanisms of action. Then, the marine-derived antiangiogenic protein kinase inhibitors will be focused on. And finally, the clinical trials of the marine-derived antiangiogenic agents will be discussed, with special emphasis on their application potentials, problems and possible coping strategies in their future development as anticancer drugs.
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The effect of anesthetic technique on survival in human cancers: a meta-analysis of retrospective and prospective studies.
PLoS ONE
PUBLISHED: 01-10-2013
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Animal models have shown that regional anesthesia (combined with or without general anesthesia) would attenuate the surgical stress response by preserving immune function and result in better long-term outcome. In order to test the hypothesis that cancer patients who had surgery with epidural anesthesia (EA) would have better outcome (either overall survival [OS] or recurrence-free survival [RFS]) than those who were general anesthesia (GA), we performed this meta-analysis. By searching relevant literature, a total of 14 studies containing 18 sub-studies (seven in OS analysis and eleven in RFS analysis) were identified and meta-analyzed. Adjusted hazard ratios (HRs) with 95% confidence intervals (CIs) were used to assess the strength of association. For OS, the random-effects model was used to analyze the data and demonstrated an OS benefit in favor of EA compared with GA alone (HR = 0.84, 95% CI 0.74-0.96, P = 0.013). The influence analysis showed the robustness of the results. Specifically, a significantly positive association between EA and improved OS was observed in colorectal cancer (HR = 0.65, 95% CI 0.43-0.99, P = 0.045). For RFS, the random-effects model was used to analyze the data and no significant relationship between RFS benefit and EA (HR = 0.88, 95% CI 0.64-1.22, P = 0.457) was detected. In conclusion, our meta-analysis suggests that epidural anesthesia and/or analgesia might be associated with improved overall survival in patients with operable cancer undergoing surgery (especially in colorectal cancer), but it does not support an association between epidural anesthesia and cancer control. Prospective studies are needed to determine whether the association between epidural use and survival is causative.
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Potential prevention and treatment of maifanite for Alzheimers disease based on behavior test, oxidative stress assay, and trace element analysis in hippocampus of A?(?????)-induced AD rats.
Biol Trace Elem Res
PUBLISHED: 01-03-2013
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This study aimed to assess whether maifanite can improve the learning and memory, and antioxidant abilities of Alzheimers disease (AD) rats. The 70 rats were divided into seven groups: [A] normal control group, [B] AD model group, [C] sham group, [D] positive control group (donepezil), [E] low-dose maifanite group, [F] middle-dose maifanite group, [G] high-dose maifanite group. For [B], [D], [E], [F], and [G] groups, A?(25-35) ventricle injection was carried out, then respective medicine were administered once a day for 60 consecutive days. The step-down and step-through test were used to measure learning and memory ability. The hippocampus levels of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and malondialdehyde (MDA) were assayed. The hippocampus contents of Al, Fe, Cu, Zn, Se, and Mn were analyzed by inductively coupled plasma-atomic emission spectrometer. Maifanite decreased the acquisition errors and the retention errors while prolonging the step-down latency, and decreased the number of electric shocks while prolonging the first latency of AD rats. A?(25-35) ventricle injection initiated the decrease of SOD and GSH-Px activities and the increase of MDA content, and triggered the rise of Al, Fe, and Cu levels and the decline of Mn, Zn, and Se levels. The SOD and GSH-Px activities were enhanced followed by reduced MDA level, and the levels of Mn, Zn, and Se increased accompanied by Al, Fe, and Cu decreased in the maifanite treat groups. Maifanite could improve the learning and memory, and the antioxidant abilities of AD rats. Maifanite had the potential prevention and treatment for AD.
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Adaptation of spherical multicellular magnetotactic prokaryotes to the geochemically variable habitat of an intertidal zone.
Environ. Microbiol.
PUBLISHED: 01-01-2013
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A combination of microscopic, molecular and biogeochemical methods was used to study the structure, phylogenetics and vertical distribution of spherical multicellular magnetotactic prokaryotes (MMPs) of intertidal sediments in the Yellow Sea. These MMPs were 5.5 ?m in diameter and composed of approximately 15-30 cells. They synthesized bullet-shaped magnetites in chains or clusters. Phylogenetic analysis of 16S rRNA gene sequences suggested that these MMPs represent a novel species affiliated to the Deltaproteobacteria. To study their vertical distribution and the relationship to geochemical parameters, sediment cores were collected after the redox potential was measured in situ. The sediments were composed of yellow, grey and black layers from the surface to depth. The spherical MMPs were concentrated near the grey-black layer transition at a depth of 8-12 cm, while coccoid-shaped magnetotactic bacteria near the yellow-grey layer transition at a depth of 3-5 cm. The intertidal MMPs showed a deeper distribution at more reduced environments than coccoid-shaped magnetotactic bacteria, and MMPs in lagoon sediments. Additionally the MMPs were concentrated significantly in layers with high proportion of fine sand and total organic carbon, rich in leachable iron but poor in nitrate. These results show an adaptation of spherical MMPs to the peculiar intertidal sediment habitat.
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[High throuput analysis of organophosphorus pesticide residues and their metabolites in animal original foods by dual gas chromatography-dual pulse flame photometric detection].
Se Pu
PUBLISHED: 12-21-2011
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A method was established for the quantitative determination of 54 organophosphorus pesticide residues and their metabolites in foods of animal origin by dual gas chromatography-dual pulse flame photometric detection. Homogenized samples were extracted with acetone and methylene chloride, and cleaned-up by gel permeation chromatography (GPC). The response of each analyte showed a good linearity with a correlation coefficient not less than 0. 99. The recovery experiments were performed by a blank sample spiked at low, medium and high fortification levels. The recoveries for beef, mutton, pork, chicken were in the range of 50. 5% -128. 1% with the relative standard deviations (n = 6) of 1. 1% -25. 5%, which demonstrated the good precision and accuracy of the present method. The limits of detection for the analytes were in the range of 0. 001 -0. 170 mg/kg, and the limits of quantification were in the range of 0. 002 -0. 455 mg/kg. Animal food samples collected from markets such as meat, liver and kidney were analyzed, and the residues of dichlorovos and disulfoton-sulfoxide were found in the some samples. The established method is sensitive and selective enough to detect organophosphorus pesticide residues in animal foods.
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TGF-beta 1 codon 10 polymorphism is associated with cerebral SVD.
Can J Neurol Sci
PUBLISHED: 10-28-2011
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To clarify the role of inflammation in the pathogenesis of cerebral small vessel disease (SVD), we investigated whether the gene encoding transforming growth factor-beta 1(TGF-beta 1) is a risk factor for cerebral SVD as a whole, and for two different SVD subtypes.
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A novel genus of multicellular magnetotactic prokaryotes from the Yellow Sea.
Environ. Microbiol.
PUBLISHED: 10-06-2011
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Multicellular magnetotactic prokaryotes (MMPs) are a group of magnetotactic microorganisms composed of 10-40 Gram-negative cells. Currently, all the identified MMPs show a spherical morphology and synthesize mainly iron sulfide magnetosomes. In this study, we report a novel genus of MMPs with peculiar ellipsoidal morphology and iron oxide magnetosomes, which were discovered in intertidal sediment of the Yellow Sea in China. Optical and fluorescence microscopy revealed that this organism was ~10 × 8 µm in size and composed of ~40 cells enveloped by an outer layer. Scanning electron microscopy showed that the cells were arranged in 4-6 interlaced circles. Bullet-shaped magnetite magnetosomes were organized in chains roughly parallel to the long axis of the ellipsoidal MMPs when analysed by transmission electron microscopy. These MMPs displayed special escape motility, i.e. swimming rapidly from the edge to the centre of the droplet and then slowly back to the edge. In addition, they exhibited negative phototaxis. Light microscopy observations showed that the ellipsoidal MMPs reproduced by division along the body long axis. Both analysis of 16S rRNA gene sequence and fluorescence in situ hybridization revealed the ellipsoidal MMPs as a new genus of the Deltaproteobacteria. In summary, this novel genus of MMPs exhibit unique morphology, peculiar division process and distinct phylogenetic affiliation compared with the other MMPs.
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Drug transporter-independent liver cancer cell killing by a marine steroid methyl spongoate via apoptosis induction.
J. Biol. Chem.
PUBLISHED: 06-09-2011
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Hepatocellular carcinoma (HCC) is inherently resistant to the majority of clinical anticancer drugs. To obtain drugs that can circumvent or evade such inherent drug resistance of HCC, we investigated the effect of the marinely derived steroid methyl spongoate (MESP) on HCC cells. MESP displayed potent cell killing against a panel of six HCC cell lines, independent of their expression of drug transporters. MESP did not change the function of the drug transporters, and its cell killing was not impaired in multidrug-resistant cancer cells overexpressing the transporters. The cell killing of MESP was irrelevant to estrogen or androgen signaling and was not associated with cell cycle progression, inhibition of microtubules, and topoisomerases. In contrast, MESP potently induced apoptosis via activation of a proapoptotic caspase cascade and relief of the suppression of antiapoptotic signal transducers and activators of transcription 3 (STAT3) signaling. MESP inhibited the phosphorylation of STAT3, a critical survival signaling factor that reduced the expression of the antiapoptotic protein x-linked inhibitor of apoptosis protein but enhanced the expression of the proapoptotic protein Bax, thus promoting caspase-dependent apoptosis. These data reveal that MESP may well serve as an important candidate drug lead for HCC therapy.
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Complete genomic sequence analysis of a highly virulent isolate revealed a novel strain of Sugarcane mosaic virus.
Virus Genes
PUBLISHED: 06-05-2011
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Sugarcane mosaic virus (SCMV) is the most prevalent virus causing maize dwarf mosaic disease in northern China. A SCMV isolate, BD8, was obtained from the maize showing dwarf and mosaic symptoms in Baoding, China. The complete genomic sequence of BD8 is 9,576 nucleotides (nt) excluding the poly(A) tail. It contains one single open reading frame of 9,192 nt and encodes a large polyprotein of 3,063 amino acids (aa), flanked by a 5-untranslated region (UTR) of 148 nt and a 3-UTR of 236 nt. The entire genomic sequence of BD8 shares identities of 79.1-80.8% with those of other 13 SCMV isolates available in the GenBank at nt level, while their CP genes share identities of 76.9-82.6 and 82.8-86.9% at nt and aa levels, respectively. Phylogenetic analysis of the complete genomic sequences reveals that SCMV can be clustered to four groups: group I includes isolates from maize, group II consists of isolates from sugarcane or maize, groups III and IV contain single isolate of AU-A (AJ278405) and BD8, respectively. Thus, BD8 represents a new strain of SCMV. Furthermore analysis of the CP gene sequences of more isolates shows that BD8 is clustered to a group with the isolates from Thailand and Vietnam, which implies that isolates of this strain have been distributed in South Asia. In the greenhouse, BD8 can cause severe symptoms in all the 12 maize varieties tested with high incidence, indicating that BD8 is highly virulent.
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Design, synthesis and biological evaluation of substituted 11H-benzo[a]carbazole-5-carboxamides as novel antitumor agents.
Eur J Med Chem
PUBLISHED: 05-31-2011
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A series of novel 11H-benzo[a]carbazole-5-carboxamide derivatives were designed, synthesized and evaluated for their antitumor activity against human cancer A549 and HCT-116 cell lines. Most of the compounds showed potent antitumor activities, and compound 8 displayed remarkable in vitro and in vivo anticancer activity comparable to that of amonafide.
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The N-terminal domain of NPC1L1 protein binds cholesterol and plays essential roles in cholesterol uptake.
J. Biol. Chem.
PUBLISHED: 05-20-2011
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Niemann-Pick C1-like 1 (NPC1L1) is a multitransmembrane protein playing a crucial role in dietary and biliary cholesterol absorption. Cholesterol promotes the formation and endocytosis of NPC1L1-flotillin-cholesterol membrane microdomains, which is an early step in cholesterol uptake. How cholesterol is sensed in this step is unknown. Here, we find that the N-terminal domain (NTD) of NPC1L1 binds cholesterol. Mutation of residue Leu-216 in NPC1L1-NTD eliminates cholesterol binding, decreases the formation of NPC1L1-flotillin-cholesterol membrane microdomains, and prevents NPC1L1-mediated cholesterol uptake in culture cells and mice livers. NPC1L1-NTD specifically binds cholesterol but not plant sterols, which may account for the selective cholesterol absorption in intestine. Furthermore, 25- or 27-hydroxycholesterol competes with cholesterol to bind NPC1L1-NTD and inhibits the cholesterol induced endocytosis of NPC1L1. Together, these results demonstrate that plasma membrane-localized NPC1L1 binds exogenous cholesterol via its NTD, and facilitates the formation of NPC1L1-flotillin-cholesterol membrane microdomains that are then internalized into cells through the clathrin-AP2 pathway. Our study uncovers the mechanism of cholesterol sensing by NPC1L1 and proposes a mechanism for selective cholesterol absorption.
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Novel liver-specific cholic acid-cytarabine conjugates with potent antitumor activities: Synthesis and biological characterization.
Acta Pharmacol. Sin.
PUBLISHED: 04-25-2011
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Cytarabine is an efficient anticancer agent for acute myelogenous leukemia, but with short plasma half-life and rapid deamination to its inactive metabolite. The aim of this study was to design and synthesize novel cholic acid-cytarabine conjugates to improve its pharmacokinetic parameters.
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Effects of preconditioning with sevoflurane on TNF-?-induced permeability and activation of p38 MAPK in rat pulmonary microvascular endothelial cells.
Cell Biochem. Biophys.
PUBLISHED: 02-22-2011
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Preconditioning with sevoflurane (SPC) diminishes effusion of rat alveolar membrane during inflammation. It is not clear whether this preconditioning directly inhibits permeability of pulmonary microvascular endothelial cell (PMVEC) monolayer. In this article, we evaluated effects of SPC on permeability of PMVEC monolayer and identified signaling pathways involved in these effects. PMVEC monolayer was exposed to different conditions (5-hydroxydecanoate (5-HD), TNF-?, SPC, SPC with subsequent exposure to TNF-? and 5-HD, and SPC with subsequent exposure to TNF-? alone), and the permeability of PMVEC monolayer was assessed using FITC-bovine serum albumin (ELISA). Expression of ICAM-1 (Western blot and RT-PCR) and activation of p38 MAPK (Western blot) were also assessed. Compared to the TNF-? group, permeability of PMVEC monolayer in the SPC + TNF-? group was significantly lower. Activation of p38 MAPK was also diminished in the TNF-? group. Pre-treatment with 5-HD reverted beneficial effects of SPC. Expression of ICAM-1 was not modulated by any of the tested experimental exposures. The results of this study demonstrate that SPC is capable of diminishing the TNF-?-induced increase of permeability of PMVEC monolayer, and that this beneficial effect is partly reversed by 5-HD. Further, SPC suppresses activation of p38 MAPK.
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Palmarumycins BG1-BG7 and preussomerin BG1: establishment of their absolute configurations using theoretical calculations of electronic circular dichroism spectra.
J. Org. Chem.
PUBLISHED: 02-18-2011
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Palmarumycins BG1-BG7 (1-7), seven new compounds related to palmarumycins, were isolated from the aerial parts of Bruguiera gymnorrhiza as well as a new preussomerin derivative BG1 (8). The structures of these compounds were determined mainly by the analysis of their NMR and MS data, and their relative configurations were assigned on the basis of their (3)J(H,H) coupling constants. Compounds 4 and 7 have a sulfate group that is unprecedented among members of spirodioxynaphthalene-type natural products. The absolute configurations of 1-8 were determined by TDDFT CD calculations of the solution conformers. Compound 5 displayed inhibitory activity against HL 60 and MCF-7 cell lines.
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The comparison of various ventilation modes and the association of risk factors with CO? retention during suspension laryngoscopy.
Laryngoscope
PUBLISHED: 02-04-2011
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To compare the effectiveness of various ventilation modes during suspension laryngoscopy and to investigate risk factors associated with CO(2) retention in high-frequency jet ventilation (HFJV).
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Effective gene delivery to mesenchymal stem cells based on the reverse transfection and three-dimensional cell culture system.
Pharm. Res.
PUBLISHED: 01-31-2011
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To enhance the level and prolong the duration of gene expression for gene-engineered rat mesenchymal stem cells (MSCs) using non-viral vector.
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Derivatization of (5R)-hydroxytriptolide from benzylamine to enhance mass spectrometric detection: application to a Phase I pharmacokinetic study in humans.
Anal. Chim. Acta
PUBLISHED: 01-10-2011
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(5R)-Hydroxytriptolide, a semisynthetic structural analog of triptolide, exhibits anti-inflammatory and immunosuppressive effect both in vitro and in vivo. The compound is currently undergoing Phase I clinical trials. This work describes the quantification of (5R)-hydroxytriptolide in human plasma based on chemical derivatization from benzylamine. Analysis through liquid chromatography-tandem mass spectrometry (LC-MS/MS) is performed for characterization. The primary reaction product between (5R)-hydroxytriptolide and benzylamine was identified as a 12,13-epoxide ring adduct. For quantification in plasma, (5R)-hydroxytriptolide and the internal standard (triptolide) were first extracted from diethyl ether-dichloromethane (3:2, v/v) and then converted to their benzylamine derivates at 80°C for 1 h. The analytes are separated on a Gemini 5 ?m 100 Å column, using a gradient elution program with a solvent consisting of 0.77 mM ammonium hydroxide (pH 10.0) and acetonitrile. An API 4000 tandem mass spectrometer operated in positive ion mode and equipped with an electrospray ionization source is used as detector. This method allows for a lower limit of quantification of 0.030 ng mL(-1). The validation results show accuracy (%RE<11.7) and precision (%RSD<8.6) at a broad linear dynamic range (0.030-100 ng mL(-1)). The simple and quantitative derivatization coupled with tandem mass spectrometric analysis yields a sensitive and robust method for the quantification of (5R)-hydroxytriptolide in Phase I pharmacokinetic studies.
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Ambient air quality trends and driving factor analysis in Beijing, 1983-2007.
J Environ Sci (China)
PUBLISHED: 01-01-2011
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The rapid development in Beijing, the capital of China, has resulted in serious air pollution problems. Meanwhile great efforts have been made to improve the air quality, especially since 1998. The variation in air quality under the interaction of pollution and control in this mega city has attracted much attention. We analyzed the changes in ambient air quality in Beijing since the 1980s using the Daniel trend test based on data from long-term monitoring stations. The results showed that different pollutants displayed three trends: a decreasing trend, an increasing trend and a flat trend. SO2, dustfall, B[a]P, NO2 and PM10 fit decreasing trend pattern, while NOx showed an increasing trend, and CO, ozone pollution, total suspended particulate (TSP), as well as Pb fit the flat trend. The cause of the general air pollution in Beijing has changed from being predominantly related to coal burning to mixed traffic exhaust and coal burning related pollution. Seasonally, the pollution level is typically higher during the heating season from November to the following March. The interaction between pollution sources change and implementation of air pollution control measures was the main driving factor that caused the variation in air quality. Changes of industrial structure and improved energy efficiency, the use of clean energy and preferred use of clean coal, reduction in pollution sources, and implementation of advanced environmental standards have all contributed to the reduction in air pollution, particularly since 1998.
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Flotillins play an essential role in Niemann-Pick C1-like 1-mediated cholesterol uptake.
Proc. Natl. Acad. Sci. U.S.A.
PUBLISHED: 12-27-2010
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Dietary absorption is a major way for mammals to obtain cholesterol, which is mediated by Niemann-Pick C1-like 1 (NPC1L1) via vesicular endocytosis. One fundamental question in this process is how free cholesterol is efficiently taken up through the internalization of NPC1L1. Using exogenously expressed NPC1L1-EGFP, we show that the lipid raft proteins flotillins associate with NPC1L1 and their localization is regulated by NPC1L1 during intracellular trafficking. Furthermore, flotillins are essential for NPC1L1-mediated cellular cholesterol uptake, biliary cholesterol reabsorption, and the regulation of lipid levels in mice. Together with NPC1L1, they form cholesterol-enriched membrane microdomains, which function as carriers for bulk of cholesterol. The hypocholesterolemic drug ezetimibe disrupts the association between NPC1L1 and flotillins, which blocks the formation of the cholesterol-enriched microdomains. Our findings reveal a functional role of flotillins in NPC1L1-mediated cholesterol uptake and elucidate the formation of NPC1L1-flotillins-postive cholesterol-enriched membrane microdomains as a mechanism for efficient cholesterol absorption.
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Aphanamolide A, a new limonoid from Aphanamixis polystachya.
Org. Lett.
PUBLISHED: 12-06-2010
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Two new limonoids, namely aphanamolides A (1) and B (2), were isolated from the seeds of Aphanamixis polystachya . Their structures were established by spectroscopic methods. Aphanamolide A (1) featured an unprecedented carbon skeleton via the formation of a C-3-C-6 bond. Compounds 1 and 2 showed cytotoxic activity against two tumor cell lines.
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TGF-?1 869T/C polymorphism and ischemic stroke: sex difference in Chinese.
Can J Neurol Sci
PUBLISHED: 11-10-2010
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Inflammation plays a pivotal role in the pathogenesis of atherosclerosis and of cerebrovascular complications. Transforming growth factor-? (TGF-?) is a pleiotropic cytokine with a central role in inflammation. To investigate whether polymorphisms of the TGF-?1 gene can modify the risk of ischemic stroke (IS) in Chinese population, we conduct this hospital-based, case-control study.
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[Serrated lesions of colon and their malignant potential].
Zhonghua Bing Li Xue Za Zhi
PUBLISHED: 11-09-2010
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To study the serrated lesions of colon and to compare the malignant potential between traditional serrated adenomas (TSA) and conventional adenomas (CAD).
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[Effects of isoflurane, sevoflurane and desflurane on expression of ICAM-1 and VCAM-1 in LPS-induced rat lung microvascular endothelial cells].
Zhejiang Da Xue Xue Bao Yi Xue Ban
PUBLISHED: 10-12-2010
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To investigate the effect of isoflurane, sevoflurane and desflurane on the expression of ICAM-1 and VCAM-1 in LPS-induced rat lung microvascular endothelial cells (RLMVECs).
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Simultaneous determination of 16 pyrethroid residues in tea samples using gas chromatography and ion trap mass spectrometry.
J Chromatogr Sci
PUBLISHED: 09-30-2010
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Pyrethroids are widely used in tea production, and pesticide residues in brewed tea are becoming a major issue. Thus, an appropriate control method of pyrethroid residues in tea samples has to be developed and used to reduce the potential health hazard from consumption of pyrethroids. A method is described here for the simultaneous determination of 16 pyrethroid residues in tea samples. The insecticides were extracted using acetone and then underwent cleanup through a florisil column. Analysis was performed by gas chromatography with ion trap mass spectrometry (GC IT-MS) in MS MS mode. Retention time and specific ions were used for identification. Recoveries at spiked levels (0.001-0.2 ?g/g) for the 16 pyrethroids ranged from 71.3% to 106.3%, and the coefficient of variation was less than 17% in each case. The limits of detection were from 0.001 to 0.05 ?g/g. The proposed method was successfully applied to determine pyrethroid residues in 25 brewed made tea samples. It was found that there were bifenthrin, cyfluthrin, lamda-cyhalothrin, cypermethrin, dicofol, fenpropathrin, fenvalerate, fluvalinate, and tetramethrin residues in different samples with levels ranging from 1.18-3071.29 ?g/kg.
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[Determination of beta2-agonists and beta-blockers in urine using high performance liquid chromatography-ion trap mass spectrometry].
Se Pu
PUBLISHED: 09-30-2010
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A method has been developed for the determination of 23 beta2-agonists and 5 beta-blockers in urine samples using high performance liquid chromatography-ion trap mass spectrometry (HPLC-IT-MS). Urine samples were first deproteinized by high-speed frozen centrifugation, and the supernatants were loaded on an Extrelut diatomite column for clean-up. The analytes were eluted by ethyl acetate and concentrated for further analysis. The analytical separation was performed on an AtlantisT3-150 mm chromatographic column with the gradient elution using methanol and water (containing 0.1% formic acid). The detection was carried on a linear ion trap mass spectrometer under multiple reaction monitoring (MRM) mode with the source operated in positive mode of electrospray ionization (ESI+). Nine deuterium labeled beta2-agonists were used as internal standards for quantitative analysis. The results showed that the linear ranges for 23 beta2-agonists and 5 beta-blockers were 0.005-0.16 mg/L, and the limits of detection were all around 0.2 microg/L. The mixed standard solution was added into the blank urine samples, and the recoveries of 23 beta2-agonists and 5 beta-blockers were ranged from 57.1% to 127.7% with the relative standard deviations of 1.1%-31.1%. The results demonstrate that the method is easy, fast, sensitive, and suitable for the confirmation and quantification of 23 beta2-agonists and 5 beta-blockers in urine samples.
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