ABSTRACT
Objective: The incidence of heart valve disease is increasing worldwide and the number of heart valve replacements is expected to increase in the future. By mimicking the main tissue structures and properties of heart valve, tissue engineering offers new options for the replacements. Applying an appropriate scaffold in fabricating tissue-engineered heart valves [TEHVs] is of importance since it affects the secretion of the main extracellular matrix [ECM] components, collagen 1 and elastin, which are crucial in providing the proper mechanical properties of TEHVs
Materials and Methods: Using real-time polymerase chain reaction [PCR] in this experimental study, the relative expression levels of COLLAGEN 1 and ELASTIN were obtained for three samples of each examined sheep mitral valvular interstitial cells [MVICs]-seeded onto electrospun poly [glycerol sebacate] [PGS]-poly [?-caprolactone] [PCL] microfi-brous, gelatin and hyaluronic acid based hydrogel-only and composite [PGS-PCL/hydrogel] scaffolds. This composite has been shown to create a synthetic three-dimensional [3D] microenvironment with appropriate mechanical and biological properties for MVICs
Results: Cell viability and metabolic activity were similar among all scaffold types. Our results showed that the level of relative expression of COLLAGEN 1 and ELASTIN genes was higher in the encapsulated composite scaffolds compared to PGS-PCL-only and hydrogel-only scaffolds with the difference being statistically significant [P<0.05]
Conclusion: The encapsulated composite scaffolds are more conducive to ECM secretion over the PGS-PCL-only and hydrogel-only scaffolds. This composite scaffold can serve as a model scaffold for heart valve tissue engineering
ABSTRACT
Advertisements can influence children's health related behaviors. Television advertisements are the main avenues directing commercials at children in Iran. This study aimed to explore the content of food advertisement during children's television programs in 2007-8 and to compare it with those reported in 2000. All advertisements broadcasted before, during, and after children's programs aired on two major Iran national television networks were videotaped for a period of 4 weeks during 2007- 8. For each advertisement, type of product[s] and mode of presentation[s] were coded. A total of 229 television advertisements were broadcasted. Food commercials were the most frequent group [31%] across the two channels. Among the food products advertised, calorie dense foods, including chocolate, soft drinks, extruded cereals, ice cream, cookies and candies were the most frequent. The appeal mainly used in television food advertisements was "stimulation of hunger/thirst" [38.5%]. The advertisements were mostly presented as animations [54%] and the messages used were mainly directed to good taste. Although the total number of food advertisements during children's television programs has decreased but the consumption of high fat, high sugar, low nutrient dense foods continues to be promoted. Policies to address the issue should be scrutinized