Biomedical subjects

F T Chau

Publications and source records attributed to F T Chau.

8 recordsLinked to original sources

PubMed2004

Substitution for natural musk in Pien Tze Huang does not affect its hepatoprotective activities.

Previous studies showed that Pien Tze Huang, a Chinese folk medicine well known for its therapeutic activity in treating liver diseases, protected the liver against carbon tetrachloride (CCl4)-induced damage in mice. In the present study, natural musk, one of the important ingredients of Pien Tze Huang, was replaced by a formulated substitute, and the new formulation of Pien Tze Huang was shown to have similar chromatographic patterns to the original Pien Tze Huang in gas chromatography-mass spectrometry and high performance liquid chromatography. When used in treating mice with CCl4- or galactosamine-induced liver damage, both the original and new formulations of Pien Tze Huang were found to be able to suppress to a similar extent both the histopathological changes in the liver and the elevation of serum alanine aminotransferase and aspartate aminotransferase. Necrosis, cellular ballooning, microvesicular steatosis and lymphocytes infiltration were all significantly reduced in the damaged liver. In hepatoma cells, both formulations activated the activator protein 1 (AP1) enhancer sequence, indicating that both of them were able to act through the JNK signal transduction pathway. The results of the present study showed that the substitution for natural musk does not affect the hepatoprotective activities of Pien Tze Huang. It is also postulated that both formulations protect the liver through regulating signal transduction in the cell.

Animals↗

PubMed2001

Determination of volatile components in peptic powder by gas chromatography-mass spectrometry and chemometric resolution.

Gas chromatography-mass spectrometry (GC-MS) coupled with chemometric resolution upon two-dimensional data was proposed as a method for the analysis of volatile components in a traditional Chinese medicinal preparation peptic powder which contains Rhizoma Atractylodis, Pericarpium Citri Reticulatae, Cortex Magnoliae Officinalis and Radix Glycyrrhizae. Ninety-three components were separated and 65 of them were qualitatively and quantitatively analyzed which represented about 90.28% of the total content. With the help of chemometric resolution, the data were resolved into a pure chromatogram and a mass spectrum of each chemical component. The accuracy of qualitative and quantitative results was greatly improved by using the two-dimensional comprehensive information of chromatograms and mass spectra. The example showed that chemometric resolution could greatly enhance separation ability. This makes it possible to analyze complicated practical systems like traditional Chinese medicinal preparations with the help of coupled instruments and chemometric resolution methods.

Drugs, Chinese Herbal↗

PubMed2001

Gas chromatography-mass spectrometry and chemometric resolution applied to the determination of essential oils in Cortex cinnamomi.

In this paper, a novel procedure for qualitative and quantitative analysis of the two-dimensional data obtained from GC-MS is investigated to determine chemical components of essential oils in Cortex Cinnamomi from four different producing areas. A new method named iterative optimization procedure (IOP) specially used to resolve embedded peaks is also developed. With the help of IOP and other chemometric techniques, such as heuristic evolving latent projections, evolving factor analysis, sub-window factor analysis and orthogonal projection resolution, and etc., the detection of the purity of chromatographic peaks can be first addressed, and then the overlapping peaks are resolved into the pure chromatogram and mass spectrum of each component. The similarity searches in the MS database are finally conducted to qualitatively determine the chemical components. The results obtained showed that the accuracy of qualitative and quantitative analysis could be greatly enhanced by chemometric resolution methods. The chemometric resolution techniques upon the two-dimensional data can be quite promising tools for the analysis of the complex samples like traditional Chinese medicine.

Gas Chromatography-Mass Spectrometry↗

PubMed2001

Ultrasound-assisted extraction of ginseng saponins from ginseng roots and cultured ginseng cells.

Ultrasound-assisted extraction was evaluated as a simpler and more effective alternative to conventional extraction methods for the isolation of ginsenosides (saponins) from various types of ginseng. The ginseng samples were extracted with different solvents, under either direct sonication by an ultrasound probe horn or indirect sonication in an ultrasound cleaning bath. The ultrasonic extraction was compared with the conventional method of refluxing boiling solvents in a soxhlet extractor, on the yields of both the total saponin isolated by thin-layer chromatography and the individual ginsenosides by high performance liquid chromatography. It was found that the sonication-assisted extraction of ginseng saponins was about three times faster than the traditional extraction method. The ultrasonic extraction was not only more efficient but also convenient for the recovery and purification of the active ingredients of plant materials. In addition, the sonication-assisted extraction can be carried out at lower temperatures which are favorable for the thermally unstable compounds.

Chromatography, Thin Layer↗

PubMed1999

Application of image analysis techniques to two-dimensional crossed immunoelectrophoresis study.

Two-dimensional crossed immunoelectrophoresis (2D-CIEP) is a technique widely used for studying composition of protein mixtures in biological and clinical studies. A low cost image analysis system with the use of an optical flatbed scanner and a IBM-compatible PC was set up in this work for capturing 2D-CIEP patterns. A computer package CIEPEASY was developed for modification and analysis of the image acquired to determine various peak parameters such as the migration distance, peak height and peak area of the constituting components for both qualitative and quantitative studies. In this approach, more composition information of the standard and sample gel patterns could be extracted from the proposed image analysis system. The time required for data collection and interpretation of 2D-CIEP images was shortened significantly and the results obtained have a higher accuracy than those obtained by using conventional methods. Moreover, a linear relationship between the peak area and the amount of antigen present in a sample was confirmed accurately and reported for the first time in the literature.

Antigens↗

PubMed1998

TLCQA: quantitative study of thin-layer chromatography.

UNLABELLED: An accurate, simple and low-cost image-analysis system has been set up for capturing thin-layer chromatography images, and a software package, TLCQA, has also been developed for both qualitative and quantitative analyses using the acquired image. AVAILABILITY: Available upon request from the authors. CONTACT: bcftchau@poly.edu.hk

Chromatography, Thin Layer↗

PubMed1994

Application of a bi-directional associative memory (BAM) network in computer assisted learning in chemistry.

A computer assisted learning software based on a bi-directional associative memory (BAM) network was developed. The software was implemented to assist students in associating the names of the elements in the periodic table with their chemical symbols. The use of the BAM facilitates the analysis and interpretation of students' responses. The software package can be modified easily as an educational tool for other disciplines.

Algorithms↗

PubMed1993

SCANGRAPH: a program for digitization of graphs using an image scanner.

The program SCANGRAPH has been developed for vectorizing any drawing or graph in the form of a single continuous line. With the use of the software, the raster image of a graph in the TIFF format as generated from an optical scanner or digitizing video system can be converted to the corresponding digitized graph with x and y coordinates given. The digitized data can be output in the ASCII format for importing to other software packages. Options for peak identification, data smoothing and compression, and graph comparison are also provided for data manipulation.

Algorithms↗