Comparative analysis of machine learning methods in ligand-based virtual screening of large compound libraries.

Machine learning methods have been explored as ligand-based virtual screening tools for facilitating drug lead discovery. These methods predict compounds of specific pharmacodynamic, pharmacokinetic or toxicological properties based on their structure-derived structural and physicochemical properties. Increasing attention has been directed at these methods because of their capability in predicting compounds of diverse structures and complex structure-activity relationships without requiring the knowledge of target 3D structure. This article reviews current progresses in using machine learning methods for virtual screening of pharmacodynamically active compounds from large compound libraries, and analyzes and compares the reported performances of machine learning tools with those of structure-based and other ligand-based (such as pharmacophore and clustering) virtual screening methods. The feasibility to improve the performance of machine learning methods in screening large libraries is discussed.

Factors associated with difference in prevalence of asthma in children from three cities in China: multicentre epidemiological survey.

OBJECTIVE: To determine the factors associated with difference in prevalence of asthma in children in different regions of China. DESIGN: Multicentre epidemiological survey. SETTING: Three cities in China. PARTICIPANTS: 10,902 schoolchildren aged 10 years. MAIN OUTCOME MEASURES: Asthma and atopic symptoms, atopic sensitisation, and early and current exposure to environmental factors. RESULTS: Children from Hong Kong had a significantly higher prevalence of wheeze in the past year than those from Guangzhou and Beijing (odds ratio 1.64, 95% confidence interval 1.35 to 1.99). Factors during the first year of life and currently that were significantly associated with wheeze were cooking with gas (odds ratio 2.04, 1.34 to 3.13), foam pillows (2.58, 1.66 to 3.99), and damp housing (1.89, 1.26 to 2.83). Factors protecting against wheeze were cotton quilts and the consumption of fruit and raw vegetables. CONCLUSION: Environmental factors and diet may explain the differences in prevalence of asthma between children living in different regions of China.