Biomedical subjects

L X Yao

Publications and source records attributed to L X Yao.

5 recordsLinked to original sources

PubMed2006

Internet resources related to drug action and human response: a review.

It has been demonstrated that numerous proteins interact with drugs or their metabolites. Knowledge of these proteins is necessary to understand the mechanisms of drug action and human response. Progress in modern genetics, molecular biology, biochemistry and pharmacology is generating a comprehensive mechanistic understanding of drug-target interaction on the molecular level. This is valuable for researchers and pharmaceutical companies in their efforts to improve the efficacy of existing drugs and to discover new ones. Most recently, the integration of a systems biology approach into drug discovery processes calls for more holistic knowledge and easily accessible resources of the proteins that are important in drug action and human response. We have reviewed many publicly accessible internet resources of these proteins, according to their roles in drug action and human response, such as therapeutic effect, adverse reaction, absorption, distribution, metabolism and excretion.

Adverse Drug Reaction Reporting Systems↗

PubMed2003

KDBI: Kinetic Data of Bio-molecular Interactions database.

Understanding of cellular processes and underlying molecular events requires knowledge about different aspects of molecular interactions, networks of molecules and pathways in addition to the sequence, structure and function of individual molecules involved. Databases of interacting molecules, pathways and related chemical reaction equations have been developed. The kinetic data for these interactions, which is important for mechanistic investigation, quantitative study and simulation of cellular processes and events, is not provided in the existing databases. We introduce a new database of Kinetic Data of Bio-molecular Interactions (KDBI) aimed at providing experimentally determined kinetic data of protein-protein, protein-RNA, protein-DNA, protein-ligand, RNA-ligand, DNA-ligand binding or reaction events described in the literature. KDBI contains information about binding or reaction event, participating molecules (name, synonyms, molecular formula, classification, SWISS-PROT AC or CAS number), binding or reaction equation, kinetic data and related references. The kinetic data is in terms of one or a combination of the following quantities as given in the literature of a particular event: association/dissociation or on/off rate constant, first/second/third/. order rate constant, equilibrium rate constant, catalytic rate constant, equilibrium association/dissociation constant, inhibition constant and binding affinity constant. Each entry can be retrieved through protein or nucleic acid or ligand name, SWISS-PROT AC number, ligand CAS number and full-text search of a binding or reaction event. KDBI currently contains 8273 entries of biomolecular binding or reaction events involving 1380 proteins, 143 nucleic acids and 1395 small molecules. Hyperlinks are provided for accessing references in Medline and available 3D structures in PDB and NDB. This database can be accessed at http://xin.cz3.nus.edu.sg/group/kdbi/kdbi.asp.

DNA↗

PubMed1993

Quantitative ultrasound imaging: in vivo results in normal liver.

A method for qualitative imaging of ultrasonic backscatter levels has been implemented on a clinical imager. The method is based on comparing echo signal data from a sample or patient to echo data processed in the same way but acquired from a reference phantom. The attenuation coefficient and the backscatter coefficient of the reference phantom are known, permitting these quantities to be estimated for the sample. In the present paper, the spatial location of echo data acquisition is retained in the backscatter data analysis; quantitative "backscatter estimator" images are constructed, from which the backscatter coefficient over a region of interest may be obtained. When applied to human liver images, backscatter coefficients determined in 10 normal subjects were in approximate agreement with in vitro liver backscatter coefficients reported by previous workers.

Adolescent↗

PubMed1991

Statistical uncertainty in ultrasonic backscatter and attenuation coefficients determined with a reference phantom.

Uncertainties in measured attenuation and backscatter coefficients due to statistical fluctuations in echo signal data from a randomly scattering medium are estimated. The uncertainties are computed for the special case in which a reference phantom is employed to account for transducer and instrumentation factors when measuring attenuation and backscatter coefficients. The resultant uncertainty in the attenuation is inversely proportional to the 3/2 power of the depth range. The error in the backscatter coefficient arises both from the local fluctuation in the data and from the uncertainty in the attenuation estimate. The first of these is inversely proportional to the square root of the number of independent data points, while the second results in a contribution that is depth dependent. Predicted errors were tested by scanning tissue mimicking phantoms and estimating attenuation and backscatter coefficients for subsets of the digitized echo data. Standard deviations of the experimental results were in agreement with those predicted.

Models, Structural↗

PubMed1990

Backscatter coefficient measurements using a reference phantom to extract depth-dependent instrumentation factors.

In previous work, we demonstrated that accurate backscatter coefficient measurements are obtained with a data reduction method that explicitly accounts for experimental factors involved in recording echo data. An alternative, relative processing method for determining the backscatter coefficient and the attenuation coefficient is presented here. This method involves comparison of echo data from a sample with data recorded from a reference phantom whose backscatter and attenuation coefficients are known. A time domain processing technique is used to extract depth and frequency dependent signal ratios for the sample and the reference phantom. The attenuation coefficient and backscatter coefficient of the sample are found from these ratios. The method is tested using tissue-mimicking phantoms with known scattering and attenuation properties.

Biophysical Phenomena↗