Biomedical subjects

Feng Qiu

Publications and source records attributed to Feng Qiu.

49 records · Page 3Linked to original sources

PubMed2003

Identification of a rare sulfonic acid metabolite of andrographolide in rats.

Andrographolide is widely used in clinic as an anti-inflammatory and antibiotic drug. In this paper, the metabolites of andrographolide in rats after single oral doses of 120 mg/kg were investigated. The structures of the metabolites were elucidated by high-resolution mass spectra, NMR spectroscopy including 1H NMR, 13C NMR, and two-dimensional NMR, through comparison to a synthetic standard. The main metabolite of andrographolide in rats was 14-deoxy-12(R)-sulfo andrographolide. In the proposed mechanism, the beta-carbon of alpha, beta-unsaturated carbonyl was attacked by sulfonic acid, to form the sulfonate compound. This was a rare metabolic reaction. It may be the main metabolic pathway of andrographolide in rats. The polarity of the sulfonate metabolite increased greatly and could be easily eliminated from body.

Administration, Oral↗

PubMed2003

Six new andrographolide metabolites in rats.

Six new andrographolide metabolites M-5-M-10 were isolated from rat urine, feces, and the contents of the small intestine. Three (M-5-M-7) as sulfate ester compounds were identified as new compounds. The structures of these six metabolites were determined to be 14-deoxy-12(R)-sulfo andrographolide 3-sulfate (M-5), 14-deoxy-12(S)-sulfo andrographolide 3-sulfate (M-6), 14-sulfo isoandrographolide 3-sulfate (M-7), 14-deoxy-11,12-didehydroandrographolide (M-8), isoandrographolide (M-9), and 14-deoxy andrographolide (M-10), respectively, based on chemical evidence and spectroscopic analysis.

Animals↗

PubMed2003

[Study on the active spirostanol saponins of Gualou xiebai baijiutang].

AIM: To study the basis of actions of Gualou xiebai baijiutang. METHODS: Guided by bioactivities, chemical and chromatographic ways were applied to isolate and purify the prescription. The chemical structures were identified by chemical and spectral ways. The activities on cardiovascular system of the pure compounds were measured. RESULTS: Seven steroidal compounds were isolated and identified from the active parts. CONCLUSION: Compounds 5 and 6 showed good anti-platelet aggregation activities induced by ADP and PAF. The IC50 of compound 5 and 6 induced by 2 mumol.L-1 ADP were 0.082 and 0.078 mmol.L-1, and the IC50 induced by 0.5 mumol.L-1 PAF were 0.182 and 0.151 mmol.L-1, respectively.

Allium↗

PubMed2003

HPLC analyses and pharmacokinetic studies of baicalin and oxymatrine in rabbits.

In the present study two simple RP-HPLC methods were developed to determine baicalin and oxymatrine in rabbit serum. Separation was performed on a Diamonsil C18 column (200 mm x 4.6 mm I.D., 5 microm) with UV detector at 277 nm for baicalin and 220 nm for oxymatrine. The mobile phase was methanol-water-phosphoric acid 50:50:0.2 v/v for baicalin and acetonitrile-water (20:80, v/v, 5 mmol/L sodium octanesulfonate was contained and pH was adjusted to 3.2 with phosphoric acid for oxymatrine. p-Nitrobenzoic acid and phenacetin were used as internal standards for baicalin and oxymatrine, respectively. The standard curves were linear from 0.5 to 200.0 mg/L for baicalin and from 0.5 to 100.0 mg/L for oxymatrine with correlation coefficients of 0.9994 and 0.9965, respectively. The intra-day and inter-day RSD were less than 5.4% and 7.2% for baicalin and 6.6% and 13.8% for oxymatrine. The mean recoveries were 100.1% for baicalin and 99.1% for oxymatrine. The methods were applied to a pharmacokinetic study of baicalin and oxymatrine in rabbits. The pharmacokinetic parameters were determined after intravenous injections of baicalin and oxymatrine (40 mg/kg) separately and together to rabbits. They all fit to the two-compartment open model. Student's t test shows that there is no significant difference in the main pharmacokinetic parameters including AUC(0-infinity), when alpha and beta, when baicalin and oxymatrine were administered separately or together.

Alkaloids↗

PubMed2003

[Identification of volatile components in rat urine after oral administration of "wu-hu-tang"].

OBJECTIVE: To identify the volatile components in rat urine after oral administration of "Wu-Hu-Tang" (WHT). METHOD: GC-MS technique was applied to analyzing urine samples. RESULT: Eighteen components were detected in the WHT-treated rat urine other than the corresponding control. Among them, 14 components were identified, and 7 were also found in the extract of WHT. CONCLUSION: The above detected components might be derived from WHT, and some of them are effective components of WHT.

Administration, Oral↗

PubMed2003

[Effect of daidzein on antiarrhythmia].

OBJECTIVE: To study the effect of Daidzein on Antiarrhythmia. METHOD: The conventional antiarrhythmia methods were used. RESULT: Daidzein was remarkedly effective in preventing ventricular fibrillation induced by chloroform in mice and arrhythmia induced by aconitine in rats. The arrhythmia induced by adrenalin in rabbits was antagonized by Daidzein and it could obviously inhibit the action potential amplitude of isolated sciatic nerves in toads. And it could also prevent ventricular fibrillation induced by calcium chloride in rats, and obviously reduce the death rate of rats. Its anti-arrhythmic effect was dose-dependent. CONCLUSION: Daidzein has obvious protective effect on drug-induced arrhythmia, which may be related to its inhibition of Na+ or Ca2+ influx and its blocking beta-adrenergic receptor.

Aconitine↗

PubMed2003

[Research on active constituents research of gualou xiebai baijiutang (III). The active flavanoids].

OBJECTIVE: To observe the substance basis of actions of Gualou xiebai baijiutang. METHOD: Guided by bioactivities, the prescription was isolated and purified by chemical and chromatographic methods, and the structures were identified by chemical and spectral methods. RESULT: 4 compounds were isolated from active parts. CONCLUSION: 3 compounds were isolated for the first time from Trichosanthes kirilowii and Allium macrostemon. Compound 1 had a good activity against platelet aggregation.

Allium↗

PubMed2002

Complex-induced proximity effects. Temperature-dependent regiochemical diversity in lithiation-electrophilic substitution reactions of N-BOC-2-azabicyclo[2.1.1]hexane. 2,4- and 3,5-methanoprolines.

[reaction: see text] Azabicycle 4 and sec-butyllithium/TMEDA afford the C(1) bridgehead alpha-lithio anion at 0 degrees C. Anion quenching with carbon dioxide, methyl chloroformate, or DMF provide the bridgehead acid 8a (N-BOC-2,4-methanoproline), ester 8b, or aldehyde 8c, respectively. By contrast, at -78 degrees C these same reagents give a mixture of regioisomeric methylene and bridgehead anions whose quenching leads to mixtures of regioisomeric methylene and bridgehead acids 6a/8a, esters 6b/8b, or aldehydes 6c/8c, respectively. The previously unknown 3,5-methanoproline was prepared as its N-BOC methyl ester 6b.

Anti-Bacterial Agents↗

PubMed2002

The active constituents from Gualou-xiebai-baijiu-tang part I: active saponins.

Two new steroidal saponins and a new triterpenoidal saponin, together with nine known steroidal saponins, were isolated from "Gualou-xiebai-baijiu-tang" consisting of Fructus trichosanthis and Bulbus allii macrostemi. The structures of the three new compounds were determined as 3-O-beta-D-galactopyranosyl-hederagenin 28-O-beta-D-xylopyranosyl (1-->6)-beta-D-galactopyranosyl ester (1), spirost 25(27)-ene-2beta,3beta-diol-3-O-beta-D-glucopyranosyl (1-->2)-beta-D-galactopyranoside (2) and 26-O-beta-D-glucopyranosyl-22alpha-hydroxy-5beta-furost-25(27)-ene-1beta,3beta,6beta,26-tetraol-3-O-beta-D-galactopyranoside (3), respectively, by means of chemical evidences and spectral analysis.

Allium↗

PubMed2002

Two new steroidal saponins from "Gualou-xiebai-baijiu-tang" consisting of Fructus trichosanthis and Bulbus allii macrostemi.

Two new steroidal saponins were isolated from the Chinese folk medicine called Gualou-xiebai-baijiu-tang. The structures were determined to be spirost 25(27)-ene-2beta,3beta-diol-3-O-beta-D-glucopyranosyl(1-->2)-beta-D-galactopyranoside and 26-O-beta-D-glucopyranosyl-22alpha-hydroxy-5beta-furost-25(27)-ene-1beta,3beta,6beta,26-tetraol-3-O-beta-D-galactopyranoside, respectively, based on chemical evidences and spectral analysis.

Animals↗

PubMedDate not supplied

Lattice-based flow field modeling.

We present an approach for simulating the natural dynamics that emerge from the interaction between a flow field and immersed objects. We model the flow field using the Lattice Boltzmann Model (LBM) with boundary conditions appropriate for moving objects and accelerate the computation on commodity graphics hardware (GPU) to achieve real-time performance. The boundary conditions mediate the exchange of momentum between the flow field and the moving objects resulting in forces exerted by the flow on the objects as well as the back-coupling on the flow. We demonstrate our approach using soap bubbles and a feather. The soap bubbles illustrate Fresnel reflection, reveal the dynamics of the unseen flow field in which they travel, and display spherical harmonics in their undulations. Our simulation allows the user to directly interact with the flow field to influence the dynamics in real time. The free feather flutters and gyrates in response to lift and drag forces created by its motion relative to the flow. Vortices are created as the free feather falls in an otherwise quiescent flow.

Journal Article↗

PubMedDate not supplied

A pipeline for computer aided polyp detection.

We present a novel pipeline for computer-aided detection (CAD) of colonic polyps by integrating texture and shape analysis with volume rendering and conformal colon flattening. Using our automatic method, the 3D polyp detection problem is converted into a 2D pattern recognition problem. The colon surface is first segmented and extracted from the CT data set of the patient's abdomen, which is then mapped to a 2D rectangle using conformal mapping. This flattened image is rendered using a direct volume rendering technique with a translucent electronic biopsy transfer function. The polyps are detected by a 2D clustering method on the flattened image. The false positives are further reduced by analyzing the volumetric shape and texture features. Compared with shape based methods, our method is much more efficient without the need of computing curvature and other shape parameters for the whole colon surface. The final detection results are stored in the 2D image, which can be easily incorporated into a virtual colonoscopy (VC) system to highlight the polyp locations. The extracted colon surface mesh can be used to accelerate the volumetric ray casting algorithm used to generate the VC endoscopic view. The proposed automatic CAD pipeline is incorporated into an interactive VC system, with a goal of helping radiologists detect polyps faster and with higher accuracy.

Algorithms↗

PubMedDate not supplied

Visual simulation of heat shimmering and mirage.

We provide a physically-based framework for simulating the natural phenomena related to heat interaction between objects and the surrounding air. We introduce a heat transfer model between the heat source objects and the ambient flow environment, which includes conduction, convection, and radiation. The heat distribution of the objects is represented by a novel temperature texture. We simulate the thermal flow dynamics that models the air flow interacting with the heat by a hybrid thermal lattice Boltzmann model (HTLBM). The computational approach couples a multiple-relaxation-time LBM (MRTLBM) with a finite difference discretization of a standard advection-diffusion equation for temperature. In heat shimmering and mirage, the changes in the index of refraction of the surrounding air are attributed to temperature variation. A nonlinear ray tracing method is used for rendering. Interactive performance is achieved by accelerating the computation of both the MRTLBM and the heat transfer, as well as the rendering on contemporary graphics hardware (GPU).

Algorithms↗