Prevalence and behavioral risk factors of overweight and obesity among children aged 2-18 in Beijing, China.

OBJECTIVES: The study aimed to assess the prevalence of obesity and the related behavioral risk factors among children in Beijing. METHODS: Data were collected as part of a 2004 comprehensive study on obesity and metabolic syndrome among 21 198 children, aged 2-18 years old in Beijing. Four local and international references for the classification of childhood overweight and obesity were compared. RESULTS: The combined prevalence of obesity and overweight among children, aged 2-18 years old, was 18.7%, 21.4%, and 20.1% based on the International Obesity Task Force (IOTF) reference, new World Health Organization (WHO) growth standard, and the US 2000 Center for Disease Control and Prevention Growth Charts, respectively; and it was 21.7%, according to the local Chinese body mass index (BMI) reference for school-age children (aged 7-18 years). Physical inactivity, less sleep duration, higher consumption of alcohol, snack food and Western fast food and more screen time were associated with overweight and obesity (p<0.05). CONCLUSIONS: Over 20% of children and adolescents in Beijing are overweight or obese. Effort should be made to combat the growing obesity epidemic.

[Produce of marker-free transgenic tobacco plants by FLP/frt recombination system].

Selectable marker genes that usually encode antibiotic or herbicide resistances are widely used for the selection of the transgenic plants, but they become unnecessary and undesirable after transformation selection. An important strategy to improve the transgenic plants' biosafety is to eliminate the marker genes after successful selection. In the FLP/frt site-specific system of the 2 microm plasmid of Saccharomyces cerevisiae, the FLP enzyme efficiently catalyzes recombination between two directly repeated FLP recombination target (frt) sites, eliminating the sequence between them. By controlled expression of the FLP recombinase and specific allocation of the frt sites within transgenic constructs, the system can be applied to eliminate the marker genes after selection. Through a series of procedures, the plant FLP/frt site-specific recombination system was constructed, which included the frt containing vector pCAMBIA1300-betA-frt-als-frt and the FLP expression vector pCAMBIA1300-hsp-FLP-hpt. The FLP recombinase gene was introduced into transgenic (betA-frt-als-frt) tobacco plants by re-transformation. In re-transgenic plants, after heat shock treatment, the marker gene als flanked by two identical orientation frt sites could be excised by the inducible expression of FLP recombinase under the control of hsp promoter. Excision of the als gene was found in 41% re-transgenic tobacco plants, which indicated that this systerm could make a great contribution to obtain the marker free transgenic plants.