Metabolic syndrome is clinically defined as a cluster of abdominal obesity, atherogenic dyslipidemia, elevated blood pressure, insulin resistance. The possible mechanism of the syndrome has been suggested by clinical and epidemiological researches on each component (i.e. obesity, diabetes, dyslipidemia and hypertension). However, primary prevention of the syndrome has not fully documented. This paper summarized recent epidemiological evidence on primary preventin of metabolic syndrome through physical activity and exercise. Epidemiological studies were searched on Medline January 2000 to April 2006) using medical subject headings (MeSH) terms. Publication type (original, review); language (Japanese or English) and human studies were included. Thirty two articles were found after reviewers screened the titles and abstracts of the eighty six articles. They included 13 cross－sectional studies, 11 cohort studies and 3 randomized controlled trials (RCTs). Observational studies found lower fitness and physical inactivity are risk factors of metabolic syndrome. The subject populations of the RCTs were overweight postmenopausal women, metabolic syndrome patients and obese adolescents. There was limited and indirect evidence to support the effectiveness of exercise therapy on metabolic syndrome. ln healthy population, epidemiological studies were needed to determine risk factors and to prevent metabolic syndrome through physical activity and exercise promotion.

Ultrasound－enhanced transdermal drug delivery (TDD) is termed sonophoresis. A few studies have indicated that ultrasound frequency is associated with TDD. However, other ultrasound parameters involved in high-frequency sonophoresis and the mechanism of the effects have not been investigated in detail. The present study examines whether or not high-frequency ultrasound and its non-thermal properties enhance the transdermal delivery of fiuorescein to Wistar rats. Glass diffusion cells were attached to the abdominal skin of rats and then a topical formulation containing fluorescein was applied to the cells. An ultrasound element was fixed at the superior end of the cell and ultrasound was applied to the skin. Blood samples were then collected from the jugular vein and blood fluorescein concentrations were measured. The drug and the ultrasound element were applied to control rats without generator power. The blood fiuorescein concentration was slightly increased in control rats, but significantly increased in the rats treated with ultrasound. We found that the same energy density of ultrasound induced similar blood fiuorescein concentrations, indicating that the non－thermal properties of ultrasound enhance transdermal delivery of fluorescein to Wistar rats.