JoVE Visualize What is visualize?
Stop Reading. Start Watching.
Advanced Search
Stop Reading. Start Watching.
Regular Search
Find video protocols related to scientific articles indexed in Pubmed.
Predictors of reducing sexual and reproductive risk behaviors based on the information-motivation-behavioral skills (IMB) model among unmarried rural-to-urban female migrants in Shanghai, China.
PLoS ONE
PUBLISHED: 01-01-2013
Show Abstract
Hide Abstract
Due to the increase of premarital sex and the lack of reproductive health services, unmarried rural-to-urban female migrants experience more risks of sex and reproductive health (SRH). This study was designed to describe SRH related knowledge, attitude and risk behaviors among unmarried rural-to-urban female migrants and examine the predictors of reducing sexual and reproductive risk behaviors based on information-motivation-behavioral skills (IMB) model and to describe the relationships between the constructs.
Related JoVE Video
Poor oral bioavailability of a promising anticancer agent andrographolide is due to extensive metabolism and efflux by P-glycoprotein.
J Pharm Sci
PUBLISHED: 03-24-2011
Show Abstract
Hide Abstract
Andrographolide (AP), isolated from Andrographis paniculata (Burm. F.) Nees, is an anticancer agent with significant clinical potential. This study determined its oral bioavailability and how intestinal disposition affects its bioavailability. Pharmacokinetics was evaluated in rats. Intestinal disposition was determined using a single-pass rat intestinal perfusion model and the cultured Caco-2 cells and Madin-Darby canine kidney II cells over expressing human P-gp (MDR1-MDCKII). Absolute bioavailability of AP was 2.67%. In the duodenum and jejunum, AP was rapidly metabolized to a sulfonate, identified as 14-deoxy-12-sulfo- andrographolide. AP was also rapidly metabolized by liver S9 fraction and in blank perfusates collected from duodenum and jejunum. The apparent permeability (P(app) ) of AP from basolateral (B) to apical (A) (4.94 × 10 cm/s) in the Caco-2 model was four times higher than the P(app) from A to B (1.14 × 10(-5) cm/s). Moreover, AP was significantly more permeable in the B to A direction than the opposite direction in MDR1-MDCKII cells. In the perfusion model, the effective permeability (P*(eff) ) for AP was highest in the duodenum, followed by jejunum, and then ileum and colon. In the ileum and colon, the P*(eff) for AP was significantly increased by verapamil, a P-glycoprotein (P-gp) inhibitor. AP has poor oral bioavailability because of its rapid biotransformation and efflux by P-gp.
Related JoVE Video
Involvement of CYP3A4/5 and CYP2D6 in the metabolism of aconitine using human liver microsomes and recombinant CYP450 enzymes.
Toxicol. Lett.
PUBLISHED: 01-20-2011
Show Abstract
Hide Abstract
Aconitine (AC), a famous major Aconitum alkaloid, has effective antirheumatic function with high toxicity. The aim of our study was to in-depth investigate cytochrome P450 isozymes (CYPs) involved in aconitine metabolism in vitro. We used human liver microsomes (HLMs) as well as recombinant CYPs to investigate the metabolism pathways of aconitine by liquid chromatography-tandem mass spectrometry. Fluvoxamine maleate, gemfibrozil, amiodarone hydrochloride, omeprazole, quinidine, diethyldithiocarbamic acid and ketoconazole were successfully applied as test inhibitors for CYP1A2, CYP2C8, CYP2C9, CYP2C19*1, CYP2D6*1, CYP2E1 and CYP3A4/5 in HLMs, respectively. Six CYP-mediated metabolites were found and characterized in human liver microsomes and eight recombinant CYP isoforms. The inhibitor of CYP 3A had a strong inhibitory effect, the inhibitors of CYP 2C9, 2C8 and CYP2D6 had little inhibitory effects, whereas CYP2C19, 1A2 and 2E1 had no obvious inhibitory effects on AC metabolism. Hydroxylation and di-demethylation of aconitine were conducted by human recombinant CYP 3A5 and 2D6, dehydrogenation was only processed by CYP3A4/5, and the main CYP isoforms metabolizing aconitine to demethyl-aconitine and N-deethyl-aconitine were CYP3A4/5 and CYP2D6. In conclusion, aconitine can be transformed into at least six CYP-mediated metabolites in HLMs, CYP 3A4/5 and 2D6 were the most important CYP isoforms responsible for the de-methylation, N-deethylation, dehydrogenation, and hydroxylation of aconitine.
Related JoVE Video
Characterization of metabolites and human P450 isoforms involved in the microsomal metabolism of mesaconitine.
Xenobiotica
PUBLISHED: 11-24-2010
Show Abstract
Hide Abstract
Mesaconitine (MA), a major Aconitum alkaloid, provides effects against rheumatosis with high toxicity. To supply information for clinical safety, this study aims to investigate the metabolism of MA in male human liver microsomes (MHLMs) and the CYP isoforms involved in its metabolism. Metabolism studies were performed in vitro using MHLMs. Selective chemical inhibitors and recombinant human cytochrome P450 enzymes were used to confirm that the CYP isoforms contributed to MA metabolism. A total of nine metabolites were found and characterized in the MHLM incubations. The metabolic pathways were demethylation, dehydrogenation, hydroxylation, and demethylation-dehydrogenation. Results showed that the inhibitor of CYP3A had a strong inhibitory effect; the inhibitors of CYP2C8, CYP2C9, CYP2C19, and CYP2D6 had modest inhibitory effects, whereas inhibitors of CYP1A2 and CYP2E1 had no obvious inhibitory effects on MA metabolism. Recombinant human cytochrome P450 isoforms CYP3A4 and CYP3A5 contributed greatly to the formation of MA metabolites, and CYP2C8, CYP2C9, and CYP2D6 played a minor role in the formation of MA metabolites. MA could be transformed into at least nine metabolites in MHLMs. MA might be metabolized by CYP3A4, CYP3A5, CYP2C8, CYP2C9, and CYP2D6 in MHLMs.
Related JoVE Video
Sensitive and robust UPLC-MS/MS method to determine the gender-dependent pharmacokinetics in rats of emodin and its glucuronide.
J Pharm Biomed Anal
PUBLISHED: 09-17-2010
Show Abstract
Hide Abstract
In this study, a sensitive and robust ultraperformance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed, validated, and applied to determine gender-dependent pharmacokinetics of total emodin (aglycone+glucuronide) in male and female Sprague-Dawley rats. The lower limit of quantification for emodin and emodin glucuronide in rat plasma was 39 and 78 ng/ml, with signal-to-noise ratio of ? 10. Precision and accuracy studies showed emodin and emodin glucuronide plasma concentrations well within the 10% range in all studies. Plasma recovery of emodin and emodin glucuronide was always above 86% for low (emodin: 39 ng/ml; glucuronide: 78 ng/ml), 92% for medium (625 ng/ml), and 97% for high (10000 ng/ml) concentrations. Furthermore, emodin showed more than 95% plasma stability under short-term and long-term storage conditions, as well as after three freeze-thaw cycles in the experiments. The developed and validated analytical method was successfully applied to study the gender-dependent 10-fold higher oral bioavailability of total emodin in male than female rats. The oral bioavailability of emodin and emodin glucuronide was also measured separately and showed a statistically significant gender difference in oral bioavailability of emodin and emodin glucuronide in rats.
Related JoVE Video
Use of isoform-specific UGT metabolism to determine and describe rates and profiles of glucuronidation of wogonin and oroxylin A by human liver and intestinal microsomes.
Pharm. Res.
PUBLISHED: 03-31-2010
Show Abstract
Hide Abstract
Glucuronidation via UDP-glucuronosyltransferases (or UGTs) is a major metabolic pathway. The purposes of this study are to determine the UGT-isoform-specific metabolic fingerprint (or GSMF) of wogonin and oroxylin A, and to use isoform-specific metabolism rates and kinetics to determine and describe their glucuronidation behaviors in tissue microsomes.
Related JoVE Video
Pharmacokinetic determination of ephedrine in Herba Ephedrae and Wu Tou Tang decoctions in rats using ultra performance liquid chromatography tandem mass spectrometry.
Xenobiotica
Show Abstract
Hide Abstract
A rapid and sensitive ultra performance liquid chromatography tandem mass spectrometry method was developed and validated for the determination and quantification of ephedrine in rat plasma samples. An Acquity UPLC BEH C18 column (1.7 ?m, 2.1?mm?×?50?mm) was used for chromatographic separation. Electrospray ionization in the positive mode was used, and the precursor-fragment ion pairs of m/z 166/148 and m/z 289/97 were adopted to characterize ephedrine and testosterone (internal standard), respectively. The method was validated using 10, 100 and 500?ng/mL of ephedrine. It demonstrated adequate levels of precision and accuracy, matrix effect, extraction recovery and stability. Linearity over the concentration range of 0.5-2000?ng/mL was acceptable with a correlation coefficient (r²) better than 0.990. To determine the pharmacokinetic behaviour of this sympathomimetic compound in the Sprague-Dawley rats, ephedrine hydrochloride, Herba Ephedrae single-herb and Wu Tou Tang decoctions were administered orally, and ephedrine hydrochloride was also administered by intravenous injection, and blood samples were collected over 24?h. Ephedrine was measured in plasma and pharmacokinetic parameters were determined by using the standard non-compartmental method and calculated by using Practical Pharmacokinetic Program-Version 87/97. The AUC(0-t) and T(max) values were significantly different (p?
Related JoVE Video
A novel local recycling mechanism that enhances enteric bioavailability of flavonoids and prolongs their residence time in the gut.
Mol. Pharm.
Show Abstract
Hide Abstract
Recycling in the gastrointestinal tract is important for endogenous substances such as bile acids and for xenobiotics such as flavonoids. Although both enterohepatic and enteric recycling mechanisms are well recognized, no one has discussed the third recycling mechanism for glucuronides: local recycling. The intestinal absorption and metabolism of wogonin and wogonoside (wogonin-7-glucuronide) was characterized by using a four-site perfused rat intestinal model, and hydrolysis of wogonoside was measured in various enzyme preparations. In the perfusion model, the wogonoside and wogonin were interconverted in all four perfused segments. Absorption of wogonoside and conversion to its aglycon at the upper small intestine was inhibited in the presence of a glucuronidase inhibitor (saccharolactone) but was not inhibited by lactase phlorizin hydrolase (LPH) inhibitor gluconolactone or antibiotics. Further investigation indicated that hydrolysis of wogonoside in the blank intestinal perfusate was not correlated with bacterial counts. Kinetic studies indicated that K(m) values from blank duodenal and jejunal perfusate were essentially identical to the K(m) values from intestinal S9 fraction but were much higher (>2-fold) than those from the microbial enzyme extract. Lastly, jejunal perfusate and S9 fraction share the same optimal pH, which was different from those of fecal extract. In conclusion, local recycling of wogonin and wogonoside is the first demonstrated example that this novel mechanism is functional in the upper small intestine without significant contribution from bacteria ?-glucuronidase.
Related JoVE Video

What is Visualize?

JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

How does it work?

We use abstracts found on PubMed and match them to JoVE videos to create a list of 10 to 30 related methods videos.

Video X seems to be unrelated to Abstract Y...

In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.