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Find video protocols related to scientific articles indexed in Pubmed.
MomL, a novel marine-derived N-acyl homoserine lactonase from Muricauda olearia.
Appl. Environ. Microbiol.
PUBLISHED: 11-16-2014
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Gram-negative bacteria use N-acyl homoserine lactones (AHLs) as quorum sensing (QS) signaling molecules for interspecies communication, and AHL-dependent QS is related with virulence factor production in many bacterial pathogens. Quorum quenching (QQ), the enzymatic degradation of the signaling molecule, would attenuate virulence rather than kill the pathogens, and thereby reduce the potential for evolution of drug resistance. In a previous study, we showed that Muricauda olearia Th120, belonging to the class Flavobacteriia, has strong AHL degradative activity. In this study, an AHL lactonase (designated as MomL), which could degrade both short- and long-chain AHLs with or without a substitution of oxo-group at the C3 position, was identified from Th120. Liquid chromatography-mass spectrometry (LC-MS) analysis demonstrated that MomL functions as an AHL lactonase catalyzing AHL degradation through lactone hydrolysis. MomL is an AHL lactonase belonging to the metallo-?-lactamase superfamily that harbors an N-terminal signal peptide. The overall catalytic efficiency of MomL for C6-HSL is ?2.9×10(5) s(-1) M(-1). Metal analysis and site-directed mutagenesis showed that, compared to AiiA, MomL has a different metal-binding capability and requires the histidine and aspartic acid residues for activity, while it shares the "HXHXDH" motif with other AHL lactonases belonging to the metallo-?-lactamase superfamily. This suggests that MomL is a representative of a novel type of secretory AHL lactonase. Furthermore, MomL significantly attenuated the virulence of Pseudomonas aeruginosa in a Caenorhabditis elegans infection model, which suggests that MomL has the potential to be used as a therapeutic agent.
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Phylogenomics resolves the timing and pattern of insect evolution.
Bernhard Misof, Shanlin Liu, Karen Meusemann, Ralph S Peters, Alexander Donath, Christoph Mayer, Paul B Frandsen, Jessica Ware, Tomáš Flouri, Rolf G Beutel, Oliver Niehuis, Malte Petersen, Fernando Izquierdo-Carrasco, Torsten Wappler, Jes Rust, Andre J Aberer, Ulrike Aspöck, Horst Aspöck, Daniela Bartel, Alexander Blanke, Simon Berger, Alexander Böhm, Thomas R Buckley, Brett Calcott, Junqing Chen, Frank Friedrich, Makiko Fukui, Mari Fujita, Carola Greve, Peter Grobe, Shengchang Gu, Ying Huang, Lars S Jermiin, Akito Y Kawahara, Lars Krogmann, Martin Kubiak, Robert Lanfear, Harald Letsch, Yiyuan Li, Zhenyu Li, Jiguang Li, Haorong Lu, Ryuichiro Machida, Yuta Mashimo, Pashalia Kapli, Duane D McKenna, Guanliang Meng, Yasutaka Nakagaki, José Luis Navarrete-Heredia, Michael Ott, Yanxiang Ou, Günther Pass, Lars Podsiadlowski, Hans Pohl, Björn M von Reumont, Kai Schütte, Kaoru Sekiya, Shota Shimizu, Adam Slipinski, Alexandros Stamatakis, Wenhui Song, Xu Su, Nikolaus U Szucsich, Meihua Tan, Xuemei Tan, Min Tang, Jingbo Tang, Gerald Timelthaler, Shigekazu Tomizuka, Michelle Trautwein, Xiaoli Tong, Toshiki Uchifune, Manfred G Walzl, Brian M Wiegmann, Jeanne Wilbrandt, Benjamin Wipfler, Thomas K F Wong, Qiong Wu, Gengxiong Wu, Yinlong Xie, Shenzhou Yang, Qing Yang, David K Yeates, Kazunori Yoshizawa, Qing Zhang, Rui Zhang, Wenwei Zhang, Yunhui Zhang, Jing Zhao, Chengran Zhou, Lili Zhou, Tanja Ziesmann, Shijie Zou, Yingrui Li, Xun Xu, Yong Zhang, Huanming Yang, Jian Wang, Jun Wang, Karl M Kjer, Xin Zhou.
Science
PUBLISHED: 11-06-2014
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Insects are the most speciose group of animals, but the phylogenetic relationships of many major lineages remain unresolved. We inferred the phylogeny of insects from 1478 protein-coding genes. Phylogenomic analyses of nucleotide and amino acid sequences, with site-specific nucleotide or domain-specific amino acid substitution models, produced statistically robust and congruent results resolving previously controversial phylogenetic relations hips. We dated the origin of insects to the Early Ordovician [~479 million years ago (Ma)], of insect flight to the Early Devonian (~406 Ma), of major extant lineages to the Mississippian (~345 Ma), and the major diversification of holometabolous insects to the Early Cretaceous. Our phylogenomic study provides a comprehensive reliable scaffold for future comparative analyses of evolutionary innovations among insects.
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Age and sex-specific relationships between phthalate exposures and obesity in Chinese children at puberty.
PLoS ONE
PUBLISHED: 08-14-2014
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To examine the age and sex-specific associations of urine levels of six mono-phthalates with body size and fat distribution in Chinese children at puberty.
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Factors Associated with Pain Experience Outcome in Knee Osteoarthritis.
Arthritis Care Res (Hoboken)
PUBLISHED: 03-04-2014
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Objective: Few strategies to improve pain outcome in knee OA exist, in part because how best to evaluate pain over the long-term is unclear. Our objectives were: determine frequency of a good pain experience outcome based on previously formulated OA pain stages; and test the hypothesis that less depression and pain catastrophizing and greater self-efficacy and social support are each associated with greater likelihood of a good outcome. Methods: Study participants all with knee OA reported pain stage at baseline and 2 years. Baseline assessments utilized the Geriatric Depression Scale, Pain Catastrophizing Scale, Arthritis Self-Efficacy Scale, and MOS Social Support Survey. Using pain experience stages, good outcome was defined b persistence in or movement to no pain or stage 1 (predictable pain, known trigger) at 2 years. A multivariable logistic regression model was developed to identify independent predictors of a good outcome. Results: Of 212, 136 (64%) had a good pain outcome and 76 (36%) a poor outcome. In multivariable analysis, higher self-efficacy was associated with a significantly higher likelihood of good outcome (adjusted OR 1.14, 95% CI: 1.04-1.24); higher pain catastrophizing was associated with a significantly lower likelihood of good outcome (adjusted OR 0.88, 95% CI: 0.83-0.94). Conclusion: This stage-based measure provides a meaningful and interpretable means to assess pain outcome in knee OA. The odds of a good 2-year outcome in knee OA were lower in persons with greater pain catastrophizing and higher in persons with greater self-efficacy. Targeting these factors may help to improve pain outcome in knee OA. © 2014 American College of Rheumatology.
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Rice LTG1 is involved in adaptive growth and fitness under low ambient temperature.
Plant J.
PUBLISHED: 02-05-2014
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Low temperature (LT) is one of the most prevalent factors limiting the productivity and geographical distribution of rice (Oryza sativa L.). Although significant progress has been made in elucidating the effect of LT on seed germination and reproductive development in rice, the genetic component affecting vegetative growth under LT remains poorly understood. Here, we report that rice cultivars harboring the dominant LTG1 (Low Temperature Growth 1) allele are more tolerant to LT (15-25°C, a temperature range prevalent in high-altitude, temperate zones and high-latitude areas), than those with the ltg1 allele. Using a map-based cloning strategy, we show that LTG1 encodes a casein kinase I. A functional nucleotide polymorphism was identified in the coding region of LTG1, causing a single amino acid substitution (I357K) that is associated with the growth rate, heading date and yield of rice plants grown at LT. We present evidence that LTG1 affects rice growth at LT via an auxin-dependent process(es). Furthermore, phylogenetic analysis of this locus suggests that the ltg1 haplotype arose before the domestication of rice in tropical climates. Together, our data demonstrate that LTG1 plays an important role in the adaptive growth and fitness of rice cultivars under conditions of low ambient temperature.
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STV11 encodes a sulphotransferase and confers durable resistance to rice stripe virus.
Nat Commun
PUBLISHED: 01-14-2014
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Rice stripe virus (RSV) causes one of the most serious viral diseases of rice (Oryza sativa L.), but the molecular basis of RSV resistance has remained elusive. Here we show that the resistant allele of rice STV11 (STV11-R) encodes a sulfotransferase (OsSOT1) catalysing the conversion of salicylic acid (SA) into sulphonated SA (SSA), whereas the gene product encoded by the susceptible allele STV11-S loses this activity. Sequence analyses suggest that the STV11-R and STV11-S alleles were predifferentiated in different geographic populations of wild rice, Oryza rufipogon, and remained prevalent in cultivated indica and japonica rice varieties, respectively. Introgression of the STV11-R allele into susceptible cultivars or heterologous transfer of STV11-R into tobacco plants confers effective resistance against RSV. Our results shed new insights into plant viral defense mechanisms and suggest effective means of breeding RSV-resistant crops using molecular marker-assisted selection or genetic engineering.
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Description of Thalassotalea piscium gen. nov., sp. nov., isolated from flounder (Paralichthys olivaceus), reclassification of four species of the genus Thalassomonas as members of the genus Thalassotalea gen. nov. and emended description of the genus Thalassomonas.
Int. J. Syst. Evol. Microbiol.
PUBLISHED: 01-13-2014
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A Gram-staining-negative, aerobic, rod-shaped bacterium, designated strain T202(T), was isolated from the gill of a cultured flounder (Paralichthys olivaceus). Based on 16S rRNA gene sequence similarity, strain T202(T) was a member of the family Colwelliaceae and shared 93.32-96.58?% similarity with type strains of all members of the most closely related genus Thalassomonas. Phylogenetically, the isolate shared a root with the type strains of four marine species, Thalassomonas agariperforans M-M1(T), Thalassomonas agarivorans TMA1(T), Thalassomonas loyana CBMAI 722(T) and Thalassomonas ganghwensis JC2041(T). Optimal growth occurred in the presence of 2-4?% (w/v) NaCl, at pH 7.0-8.0 and at 28 °C. Ubiquinone 8 (Q-8) was the predominant respiratory quinone. The major fatty acids were C16?:?0, summed feature 3 (C16?:?1?7c and/or C16?:?1?6c), C16?:?1?9c and C17?:?1?8c. The major polar lipids were phosphatidylethanolamine and phosphatidylglycerol. The DNA G+C content of strain T202(T) was 37 mol%. On the basis of polyphasic analysis, especially the phylogenetic relationships and the lower DNA G+C content, strain T202(T) is considered to represent a novel species in a new genus, for which the name Thalassotalea piscium gen. nov., sp. nov. is proposed. The type strain of Thalassotalea piscium is T202(T) (?=?JCM 18590(T)?=?DSM 26287(T)?=?KCTC 32144(T)). Because Thalassomonas agariperforans M-M1(T), Thalassomonas agarivorans TMA1(T), Thalassomonas loyana CBMAI 722(T) and Thalassomonas ganghwensis JC2041(T) formed a phylogenetic group together with strain T202(T) that was clearly separated from other known strains of Thalassomonas, these four species are reclassified as members of the genus Thalassotalea as Thalassotalea agariperforans comb. nov. (type strain M-M1(T)?=?KCTC 23343(T)?=?CCUG 60020(T)), Thalassotalea agarivorans comb. nov. (type strain TMA1(T)?=?BCRC 17492(T)?=?JCM 13379(T)?=?DSM 19706(T)), Thalassotalea loyana comb. nov. (type strain CBMAI 722(T)?=?LMG 22536(T)) and Thalassotalea ganghwensis comb. nov. (type strain JC2041(T)?=?IMSNU 14005(T)?=?KCTC 12041(T)?=?DSM 15355(T)). The type species of the genus Thalassotalea is Thalassotalea ganghwensis gen. nov., comb. nov. An emended description of the genus Thalassomonas is also proposed.
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Flaviramulus ichthyoenteri sp. nov., an N-acylhomoserine lactone-degrading bacterium isolated from the intestine of a flounder (Paralichthys olivaceus), and emended descriptions of the genus Flaviramulus and Flaviramulus basaltis.
Int. J. Syst. Evol. Microbiol.
PUBLISHED: 07-16-2013
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A Gram-stain-negative, strictly aerobic, yellow-pigmented, rod-shaped and N-acylhomoserine lactone-degrading bacterium, designated strain Th78(T), was isolated from the intestine of a cultured flounder (Paralichthys olivaceus). Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain Th78(T) belonged to the genus Flaviramulus (family Flavobacteriaceae) and showed the highest 16S rRNA gene sequence similarity to Flaviramulus basaltis H35(T) (96.70?%). Optimal growth occurred in the presence of 2-3?% (w/v) NaCl, at pH 7.0-8.0 and at 28 °C. The major fatty acids were iso-C15?:?0 3-OH, iso-C15?:?1 G and iso-C17?:?0 3-OH. The major polar lipids were phosphatidylethanolamine, one unidentified aminolipid and three unidentified polar lipids. Menaquinone 6 (MK-6) was the only respiratory quinone. The DNA G+C content of strain Th78(T) was 31.5 mol%. On the basis of polyphasic analysis, strain Th78(T) is considered to represent a novel species of the genus Flaviramulus, for which the name Flaviramulus ichthyoenteri sp. nov. is proposed. The type strain is Th78(T) (?=?JCM 18634(T)?=?KCTC 32142(T)?=?DSM 26285(T)). Emended descriptions of the genus Flaviramulus and Flaviramulus basaltis are also proposed.
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A role for a dioxygenase in auxin metabolism and reproductive development in rice.
Dev. Cell
PUBLISHED: 06-27-2013
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Indole-3-acetic acid (IAA), the natural auxin in plants, regulates many aspects of plant growth and development. Extensive analyses have elucidated the components of auxin biosynthesis, transport, and signaling, but the physiological roles and molecular mechanisms of auxin degradation remain elusive. Here, we demonstrate that the dioxygenase for auxin oxidation (DAO) gene, encoding a putative 2-oxoglutarate-dependent-Fe (II) dioxygenase, is essential for anther dehiscence, pollen fertility, and seed initiation in rice. Rice mutant lines lacking a functional DAO display increased levels of free IAA in anthers and ovaries. Furthermore, exogenous application of IAA or overexpression of the auxin biosynthesis gene OsYUCCA1 phenocopies the dao mutants. We show that recombinant DAO converts the active IAA into biologically inactive 2-oxoindole-3-acetic acid (OxIAA) in vitro. Collectively, these data support a key role of DAO in auxin catabolism and maintenance of auxin homeostasis central to plant reproductive development.
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Determination of Prostaglandin E1 in dog plasma using liquid chromatography-tandem mass spectrometry and its application to a pharmacokinetic study.
J. Chromatogr. B Analyt. Technol. Biomed. Life Sci.
PUBLISHED: 06-21-2013
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The determination of Prostaglandin (PG) E1 in plasma is challenged by its low concentration (pg/mL) and endogenous interference. An LC-MS/MS method for the determination of PGE1 in dog plasma has been developed and validated. Plasma being sampled at 4°C and treated with indomethacin effectively inhibited interferents synthesized post-sampling. Samples were subjected to one-step extraction and separated by reversed phase HPLC with a short cycle time of 3min. An LLOQ of 10pg/mL was achieved with 500?l plasma. The method was applied to a pharmacokinetic study in beagle dogs involving an intravenous infusion of 3.2?g/kg PGE1. The half-life was recovered at 7min. The simple, sensitive and rapid method was suitable to be applied to pharmacokinetic studies of PGE1 at clinically relevant doses.
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One step, two steps, three steps more ... Directional vulnerability to falls in community-dwelling older people.
J. Gerontol. A Biol. Sci. Med. Sci.
PUBLISHED: 05-17-2013
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Falls leading to disability are common occurrences with advancing age. Stepping is a natural protective option for maintaining balance and preventing falls. There are directionally dependent challenges for protective stepping associated with falls among older individuals. The aim of this study was to determine the stepping response patterns evoked by different directions of externally applied postural disturbances in younger and older adults and in relation to falls.
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Stepping in persons poststroke: comparison of voluntary and perturbation-induced responses.
Arch Phys Med Rehabil
PUBLISHED: 05-03-2013
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To examine the stepping performance during voluntary and waist-pull perturbation-induced step initiation in people with chronic stroke.
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Evaluation of a new high-throughput method for identifying quorum quenching bacteria.
Sci Rep
PUBLISHED: 04-29-2013
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Quorum sensing (QS) is a population-dependent mechanism for bacteria to synchronize social behaviors such as secretion of virulence factors. The enzymatic interruption of QS, termed quorum quenching (QQ), has been suggested as a promising alternative anti-virulence approach. In order to efficiently identify QQ bacteria, we developed a simple, sensitive and high-throughput method based on the biosensor Agrobacterium tumefaciens A136. This method effectively eliminates false positives caused by inhibition of growth of biosensor A136 and alkaline hydrolysis of N-acylhomoserine lactones (AHLs), through normalization of ?-galactosidase activities and addition of PIPES buffer, respectively. Our novel approach was successfully applied in identifying QQ bacteria among 366 strains and 25 QQ strains belonging to 14 species were obtained. Further experiments revealed that the QQ strains differed widely in terms of the type of QQ enzyme, substrate specificity and heat resistance. The QQ bacteria identified could possibly be used to control disease in aquaculture.
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Site-specific methylation of placental HSD11B2 gene promoter is related to intrauterine growth restriction.
Eur. J. Hum. Genet.
PUBLISHED: 03-03-2013
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Intrauterine growth restriction (IUGR) is associated with detrimental effects on neurodevelopmental progress in childhood and higher risk of degenerative diseases in adulthood. Placental 11?-hydroxysteroid dehydrogenase (HSD11B2) is a key gene involved in glucocorticoid metabolism, which in turn seems to be related to fetal growth impairment. As reduction of placental HSD11B2 gene expression has been associated with reduced human fetal growth, and methylation of HSD11B2 gene promoter has been shown to have an important role in HSD11B2 gene repression, we seek to investigate the relationship between IUGR and HSD11B2 gene promoter methylation in human placentas. We found that methylation levels of all studied CpG sites were significantly higher in IUGR newborns than those in controls. Further, methylation levels of the first and the third CpG sites were inversely associated with measures of fetal growth (birth weight and ponderal index). In addition, consistent with the above negative correlation, methylation levels of the first and the third CpG sites were inversely associated with HSD11B2 gene expression. These results together show a link between the site-specific methylation of placental HSD11B2 promoter and the development of IUGR.European Journal of Human Genetics advance online publication, 16 October 2013; doi:10.1038/ejhg.2013.226.
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Metabonomics study of essential hypertension and its chinese medicine subtypes by using gas chromatography-mass spectrometry and nuclear magnetic resonance spectroscopy.
Evid Based Complement Alternat Med
PUBLISHED: 02-25-2013
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A metabonomic study was performed to investigate the metabolic mechanism of essential hypertension and its Chinese medicine subtypes, including "Yin-deficiency and Yang-hyperactivity syndrome" (YDYHS) and "Yin-Yang deficiency syndrome" (YYDS). Plasma samples from 22 healthy volunteers, 31 hypertensive patients with YDYHS, and 29 hypertensive patients with YYDS were analyzed by (1)H-NMR spectroscopy and gas chromatography coupled with mass spectrometry (GC-MS). The three groups were distinctly classified by principal components analysis (PCA) and partial least squares discriminant analysis (PLS-DA). According to identified biomarkers and their related pathways, abnormal glucose metabolism might be the main common pathway from YDYHS to YYDS, and sympathetic nervous system activation would play an important role in the pathogenesis of YDYHS, while a low metabolic rate usually occurred in YYDS.
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Postural preparation prior to stepping in patients with Parkinsons disease.
J. Neurophysiol.
PUBLISHED: 04-27-2011
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People with Parkinsons disease (PD) frequently have difficulties with generating anticipatory postural adjustments (APAs) for forward propulsion and lateral weight transfer when initiating gait. This impairment has been attributed to deficits in motor planning and preparation. This study examined the preparation of APAs prior to an imperative cue to initiate forward stepping. A startling acoustic stimulus (SAS) was used to probe the state of preparation of the APA in eight PD (off medication) and seven matched control subjects. Subjects performed visually cued trials involving a pre-cue light instructing them to prepare to step, followed 3.5 s later by a go-cue light to rapidly initiate stepping. In random trials, a SAS (124 dB) was presented at -1,500, -1,000, -500, -250, -100, or 0 ms before the go-cue. Subjects also performed self-initiated steps. Ground reaction forces (GRFs), center of pressure (CoP) changes, and electromyographic (EMG) signals were recorded. The SAS triggered APAs in 94 ± 11% (PD) and 96 ± 8% (control) of trials at latencies 89 ± 4 ms (PD) and 97 ± 3 ms (control) earlier than Control trials. The temporal profile of APA preparation was similar between groups. However, peak EMG, GRF, and mediolateral CoP amplitudes were reduced in PD. SAS-evoked APAs at 0 ms matched Control trial APAs and were enhanced compared with self-initiated stepping. These results demonstrate that people with mild to moderate PD can plan and prepare the appropriate APA sequence prior to the expected cue to initiate gait; however, the prepared APAs are underscaled in magnitude.
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Synthesis and SAR of indole-and 7-azaindole-1,3-dicarboxamide hydroxyethylamine inhibitors of BACE-1.
Bioorg. Med. Chem. Lett.
PUBLISHED: 04-16-2011
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Heterocyclic replacement of the isophthalamide phenyl ring in hydroxyethylamine (HEA) BACE-1 inhibitors was explored. A variety of indole-1,3-dicarboxamide HEAs exhibited potent BACE-1 enzyme inhibition, but displayed poor cellular activity. Improvements in cellular activity and aspartic protease selectivity were observed for 7-azaindole-1,3-dicarboxamide HEAs. A methylprolinol-bearing derivative (10n) demonstrated robust reductions in rat plasma A? levels, but did not lower rat brain A? due to poor central exposure. The same analog exhibited a high efflux ratio in a bidirectional Caco-2 assay and was likely a substrate of the efflux transporter P-glycoprotein. X-ray crystal structures are reported for two indole HEAs in complex with BACE-1.
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Effect of brominated flame retardant BDE-47 on androgen production of adult rat Leydig cells.
Toxicol. Lett.
PUBLISHED: 04-06-2011
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As one of the most abundant polybrominated diphenylethers (PBDEs) detected in adipose tissue and breast milk of humans, 2,2,4,4-tetrabromodiphenyl ether (BDE-47) is considered as a potential endocrine disruptor. The objective of this study is to explore whether environment-related level of BDE-47 could affect the androgen production in rat Leydig cells. Rat adult Leydig cells (ALCs) were treated with 10(-8) to 10(-4)M BDE-47 in vitro, the production of testosterone (T) and steroidogenic acute regulatory (StAR) protein level were determined. BDE-47 significantly increased basal T production and steroidogenic acute regulatory protein (StAR) level of ALCs after treatment with 10(-4)M BED-47. Overall, LH (0.1ng/ml) stimulated T production in ALCs by 6 folds, however it did not increase T production in BDE-47-treated ALCs when compared to untreated ALC. Both 8-Br-cAMP (for cAMP signaling) and 22R-hydroxycholesterol (22-diol, for P450 cholesterol side chain cleavage enzyme P450scc activity) significantly increased T production in ALCs treated with BDE-47 from 10(-7) to 10(-5)M. The results of this study indicate that environment-related level of BDE-47 in vitro increased T production in a dose-dependent manner. The stimulated effects of BDE-47 on StAR and P450scc might play key roles in BDE-47-mediated stimulation of T production.
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Development and validation of an improved method for the quantitation of sertraline in human plasma using LC-MS-MS and its application to bioequivalence studies.
J Chromatogr Sci
PUBLISHED: 01-13-2011
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A rapid and sensitive LC-MS-MS method for the quantitation of sertraline in human plasma was developed and validated. Sertraline and the internal standard, telmisartan, were cleaned up by protein precipitation from 100 ?L of plasma sample, and analyzed on a TC-C18 column (5 ?m, 150 × 4.6 mm i.d.) using 70% acetonitrile and 30% 10 mM ammonium acetate (0.1% formic acid) as mobile phase. The method was demonstrated to be linear from 0.1 ng/mL to 50 ng/mL with the lower limit of quantitation of 0.1 ng/mL. Intra- and inter-day precision were below 4.40% and 3.55%. Recoveries of sertraline at low, medium, and high levels were 88.0 ± 2.3%, 88.2 ± 1.9%, and 90.0 ± 2.0%, respectively. The method was successfully applied to a bioequivalence study of sertraline after a single oral administration of 50 mg sertraline hydrochloride tablets.
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Part 1. A time-series study of ambient air pollution and daily mortality in Shanghai, China.
Res Rep Health Eff Inst
PUBLISHED: 08-31-2010
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Although the relation between outdoor air pollution and daily mortality has been examined in several Chinese cities, there are still a number of key scientific issues to be addressed concerning the health effects of air pollution in China. Given the changes over the past decade in concentrations and sources of air pollution (e.g., the change from one predominant source [coal combustion], which was typical of the twentieth century, to a mix of sources [coal combustion and motor-vehicle emissions]) and transition in China, it is worthwhile to investigate the acute effects of outdoor air pollution on mortality outcomes in the country. We conducted a time-series study to investigate the relation between outdoor air pollution and daily mortality in Shanghai using four years of daily data (2001-2004). This study is a part of the Public Health and Air Pollution in Asia (PAPA) program supported by the Health Effects Institute (HEI). We collected data on daily mortality, air pollution, and weather from the Shanghai Municipal Center of Disease Control and Prevention (SMCDCP), Shanghai Environmental Monitoring Center, and Shanghai Meteorologic Bureau. An independent auditing team assigned by HEI validated all the data. Our statistical analysis followed the Common Protocol of the PAPA program (found at the end of this volume). Briefly, a natural-spline model was used to analyze the mortality, air pollution, and covariate data. We first constructed the basic models for various mortality outcomes excluding variables for air pollution, and used the partial autocorrelation function of the residuals to guide the selection of degrees of freedom for time trend and lag days for the autoregression terms. Thereafter, we introduced the pollutant variables and analyzed their effects on mortality outcomes, including both mortality due to all natural (nonaccidental) causes and cause-specific mortality. We fitted single- and multipollutant models to assess the stability of the effects of the pollutants. For mortality due to all natural causes, we also examined the associations stratified by sex and age. Stratified analyses by education level, used as a measure of socioeconomic status, were conducted as well. In addition to an analysis of the entire study period, the effects of air pollution in just the warm season (from April to September) and cool season (from October to March) were analyzed. We also examined the effects of alternative model specifications--such as lag effects of pollutants and temperature, degrees of freedom for time trend and weather conditions, statistical approaches, and averaging methods for pollutant concentrations-on the estimated effects of air pollution. We found significant associations between the air pollutants--particulate matter 10 pm or less in aerodynamic diameter (PM10), sulfur dioxide (SO2), nitrogen dioxide (NO2), and ozone (O3) -and daily mortality from all natural causes and from cardiopulmonary diseases. The increased mortality risks found in the data from Shanghai were generally similar in magnitude, per concentration of pollutant, to the risks found in research from other parts of the world. An increase of 10 microg/m3 in 2-day moving average concentrations of PM10, SO2, NO2, and O3 corresponded to 0.26% (95% confidence interval [CI], 0.14-0.37), 0.95% (95% CI, 0.62-1.28), 0.97% (95% CI, 0.66-1.27), and 0.31% (95% CI, 0.04-0.58) increases, respectively, in mortality due to all natural causes. Sensitivity analyses suggested that our findings were generally insensitive to alternative model specifications. We found significant effects of the gaseous pollutants SO2 and NO2 on daily mortality after adjustment for PM10. Our analysis also provided preliminary, but not conclusive, evidence that women, older people, and people with a low level of education might be more vulnerable to air pollution than men, younger people, and people with a high level of education. In addition, the associations between air pollution and daily mortality appeared to be more pronounced in the cool season than in the warm. We concluded that short-term exposure to outdoor air pollution (PM10, SO2, NO2, and O3) was associated with daily mortality in Shanghai and that gaseous pollutants might have independent health effects in the city. Overall, the results of the study appeared largely consistent with those reported in other locations worldwide. Further research will be needed to disentangle the effects of the various pollutants and to gain more conclusive insights into the influence of various sociodemographic characteristics (e.g., sex, age, and socioeconomic status) and of season on the associations between air pollution and daily mortality.
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Perturbations of ground support alter posture and locomotion coupling during step initiation in Parkinsons disease.
Exp Brain Res
PUBLISHED: 08-23-2010
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During the initiation of stepping, anticipatory postural adjustments (APAs) for lateral weight transfer and propulsion normally precede the onset of locomotion. In Parkinsons disease (PD), impaired step initiation typically involves altered APA ground force production with delayed step onset and deficits in stepping performance. If, as in stance and gait, sensory information about lower limb load is important for the control of stepping, then perturbations influencing loading conditions could affect the step initiation process. This study investigated the influence of changes in lower limb loading during step initiation in patients with PD and healthy control subjects. Participants performed rapid self-triggered step initiation with the impending single stance limb positioned over a pneumatically actuated platform. In perturbation trials, the stance limb ground support surface was either moved vertically downward (DROP) or upward (ELEVATE) by 1.5 cm shortly after the onset of the APA phase. Overall, PD patients demonstrated a longer APA duration, longer time to first step onset, and slower step speed than controls. In both groups, the DROP perturbation reinforced the intended APA kinetic changes for lateral weight transfer and resulted in a significant reduction in APA duration, increase in peak amplitude, and earlier time to first step onset compared with other conditions. During ELEVATE trials that opposed the intended weight transfer forces both groups rapidly adapted their stepping to preserve standing stability by decreasing step length and duration, and increasing step height and foot placement laterally. The findings suggested that sensory information associated with limb load and/or foot pressure modulates the spatial and temporal parameters of posture and locomotion components of step initiation in interaction with a centrally generated feedforward mode of neural control. Moreover, impaired step initiation in PD may at least acutely be enhanced by augmenting the coupling between posture and locomotion.
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Applying solubilization treatment to reverse clogging in laboratory-scale vertical flow constructed wetlands.
Water Sci. Technol.
PUBLISHED: 03-31-2010
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Substrate clogging is characterized as a frequently occurring operational problem for subsurface-flow constructed wetlands. The application of solubilization treatment to reduce clogging was tested in lab-scaled setups to provide a promising solution. The performance of solubilization treatment on reducing clogging and the related effects on plants and biofilms in the wetland system were investigated in this paper. The results showed that the infiltration rate and available porosity of wetland substrate increased as a function of increased dosage of NaOH, HCl, NaClO, and detergent, respectively. Among the four solvents, it appeared that NaClO had the most obvious effects on reducing clogging and the infiltration rate and effective porosity recovered to 69% of the original condition. The two possible reasons for solubilization were the flocculents structure of the clogs was broken up or parts of the organic clogs were dissolved. The function of adding NaOH and NaClO was to dissolve the protein and polysaccharides of the organic clogs; the function of adding HCl was to release the anaerobic gas wrapped in the organic clogs. Furthermore, experiments results also showed that the solubilized solvents did not demonstrate a long-term negative effect on plants and biofilms.
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Short-term effects of posture-assisted step training on rapid step initiation in Parkinsons disease.
J Neurol Phys Ther
PUBLISHED: 06-27-2009
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Anticipatory postural adjustments (APAs) for lateral weight transfer and stability precede and accompany gait initiation. Individuals with Parkinsons disease (PD) show altered APA characteristics with delays in initiating stepping that may reflect impaired interactions between posture and locomotion. The purpose of this study was to determine the short-term effects of a single session of repetitive robotic assistance training with the APA on rapid step initiation in individuals with PD in the medications "on" state and healthy control individuals. Ground reaction forces and step kinematics were recorded.
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Quantitation of bergenin in human plasma by liquid chromatography/tandem mass spectrometry.
J. Chromatogr. B Analyt. Technol. Biomed. Life Sci.
PUBLISHED: 03-14-2009
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This paper reports the development and validation of an assay for quantitation of bergenin in human plasma using liquid chromatography/tandem mass spectrometry (LC-MS/MS). Bergenin and the internal standard (I.S.), 5-bromo-2,4(1H,3H)-pyrimidinedione (5-BrU), were separated by reversed phase HPLC and quantitated by MS/MS using electrospray ionization (ESI) and multiple reaction monitoring (MRM) in the negative ion mode. The most intense [M-H](-) MRM transition of bergenin at m/z 326.9-->312.3 was used for quantitation and the transition at m/z 188.9-->42.2 was used to monitor 5-BrU. Stability issues with bergenin required the addition of ascorbic acid to plasma samples prior to storage and analysis within 10 days storage at -80 degrees C. The method was linear in the range 3-1000 ng/mL with intra- and inter-day precision of 3.94-5.96 and 1.62-8.31%, respectively, and accuracy <2.33%. The assay was successfully applied to a pharmacokinetic study in healthy volunteers after administration of a single 250 mg oral dose.
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Phthalate levels and low birth weight: a nested case-control study of Chinese newborns.
J. Pediatr.
PUBLISHED: 03-10-2009
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To assess maternal-fetal exposure to phthalates and investigate whether in utero phthalate exposure is associated with low birth weight (LBW).
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Synthesis and SAR of hydroxyethylamine based phenylcarboxyamides as inhibitors of BACE.
Bioorg. Med. Chem. Lett.
PUBLISHED: 03-02-2009
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A series of N-((2S,3R)-1-(3,5-difluorophenyl)-3-hydroxy-4-(3-methoxybenzylamino)-butan-2-yl)benzamides has been synthesized as BACE inhibitors. A variety of P2 and P3 substituents has been explored, and these efforts have culminated in the identification of several 1,3,5-trisubstituted phenylcarboxyamides with potent BACE inhibitory activity.
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In utero and lactational exposures to diethylhexyl-phthalate affect two populations of Leydig cells in male Long-Evans rats.
Biol. Reprod.
PUBLISHED: 01-14-2009
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Diethylhexylphthalate (DEHP) has been classified as an antiandrogen. However, whether in utero and lactational exposures of DEHP affect Leydig cells has not been well established. In the present study, the effects of DEHP exposures on fetal Leydig cells (FLCs) and adult Leydig cells (ALCs) were assessed. Pregnant dams of Long-Evans rats were treated with 0, 10, and 750 mg/kg body weight DEHP from Gestational Day 12.5 to Postnatal Day (PND) 21.5. Fetal Leydig cell clustering and FLC-specific gene expression were examined. Anogenital distances (AGDs) of male pups were assessed at PND 2. Serum testosterone levels of male pups and mRNA levels of ALC-specific genes were measured at PNDs 21 and 49. The AGDs of male pups were significantly shorter in the group treated with 750 mg/kg DEHP (mean +/- SEM, 3.68 +/- 0.16 mm) compared with control (4.62 +/- 0.13 mm). The FLCs were aggregated after 10 and 750 mg/kg DEHP exposures. Several FLC-specific genes, including luteinizing hormone receptor (Lhcgr) and steroidogenic enzyme genes, were downregulated at both doses. Serum testosterone levels were significantly lower compared with control at PND 21 after treatment of 10 or 750 mg/kg DEHP, and continued to be lower even up to 49 days postpartum at the higher dose. The mRNA levels for Lhcgr and steroidogenic enzyme genes were significantly lower at both doses of DEHP at PND 21, whereas there were no significant differences for these genes at PND 49. In conclusion, in utero and continued lactational exposures to DEHP exert long-term disruption of steroidogenesis of ALCs.
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Exposure assessment of phthalates in non-occupational populations in China.
Sci. Total Environ.
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Phthalates have been used worldwide and are ubiquitous in environmental media and human bodies. Based on existing data on phthalate concentrations, distributions of phthalates in the environment and their exposure assessment to non-occupational populations in China can be evaluated. Fifty-three studies, published from January 2000 to October 2010, were reviewed and their data were analyzed in this study. Geographic information system (GIS) was used in mapping the published data of phthalate concentrations and their distributions in environmental media, while scatter diagrams were applied to show the time trends for phthalate concentrations in various environmental media. Results showed that there was a time-dependent increase in ?phthalates (total phthalates) and DEHP concentrations in air during the past 10 years; phthalate concentrations varied in different areas, among which Guangdong and northeast China were the most polluted. Using Clarks equations, daily intake of ?phthalates and DEHP in the Pearl River Delta and the Yangtze River Delta was estimated from consumption of contaminated food, water and air. Results showed that daily intake of ?phthalates and DEHP was 128.63 and 61.29 ?g/kg BW/d for adults in the Pearl River Delta, which is significantly higher than those residing in the Yangtze River Delta (33.87 and 24.68 ?g/kg BW/d).
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Mono-(2-ethylhexyl) phthalate affects the steroidogenesis in rat Leydig cells through provoking ROS perturbation.
Toxicol In Vitro
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Di-2-ethylhexyl phthalate (DEHP), one of the most widely used plasticizers in a number of day-life products, exerts both short-term and long-lasting effects on testicular steroidogenesis during in utero exposure. These actions might be caused by its primary metabolite, mono-(2-ethylhexyl) phthalate (MEHP). In the present study, we investigated the effects of MEHP on steroidogenesis of different stages of rat Leydig cells, progenitor (PLCs), immature (ILCs) and adult (ALCs). Results showed that MEHP affected reactive oxygen species (ROS) generation as well as androgen production in ALCs, but not in PLCs and ILCs, which coincided with hydrogen peroxide (H(2)O(2)). Low concentrations of MEHP (20-200?M) provoked ROS perturbation and caused the stimulation of steroidogenic acute regulatory (StAR), cytochrome P450 side-chain cleavage (P450scc), 3?-hydroxysteroid dehydrogenases (3?-HSD) and 17?-hydroxysteroid dehydrogenases (17?-HSD) activities which elevated T production of ALCs. Contrast to the effect in low doses, high levels of MEHP (2000?M and over) induced overloaded oxidative stress and inhibited steroidogenesis by reducing the activities of these enzymes in ALCs. These results indicated that oxidative stress and subsequent steroidogenic enzymes changes in ALCs were the potential underlying mechanism of the biphasic effects of DEHP on androgen production.
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[Progress on the research of stem Leydig cell line in the testis of rodents].
Wei Sheng Yan Jiu
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Objective: Leydig cells are the primary source of generating testosterone, and the differentiation of Leydig cells in testes is a signature event of the ontogenesis of males. Many studies elucidating the molecular changes and the mechanisms involved in the progressive differentiation of stem Leydig cells into adult Leydig cells have been appeared recently. Herein, the hormonal regulation on the ontogenesis of fetal and mature Leydig cells was reviewed in this paper.
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