Evaluation of dermal irritancy potential of Carboxymethyl-chitosan hydrogel and poly-(acrylic acid) chitin hydrogel.

OBJECTIVE: The wound dressing synthesized from carboxymethylchitosan hydrogel (CM) and chitin-(polyacrylic acid) hydrogel (PAA) were examined for their dermal irritation potential response using the Draize test. MATERIAL AND METHOD: Eighteen male Sprague-Dawley rats were divided into three groups (6 rats/each). Rats in group 1 were designed as control, group 2 were treated with CM, and group 3 were treated with PAA. The test materials diameter 1 x 1 cm were topically applied on the skin in group 2 and 3. Two skin sites (1 x 1 cm in size) were located at the back. One site was intact and the other was abraded in such a way the stratum corneum had no bleeding. RESULT: After 24 and 72 hours of wrappings, the materials were removed and the test sites were evaluated in terms of erythema and edema using adopted Draize scoring system. At the end of the experiment, all rats were anesthesized with intravenous thiopental sodium. Blood samples from descending aorta were collected for liver and kidney function test and all organs were weighed. The results of this experiment showed 1) no irritation of both materials in this animal model; 2) no material-related induced liver and kidney dysfunction and 3) organ weights had no significant difference between the groups. CONCLUSION: Both CM and PAA should be considered safe to use in the purpose of wound dressing in further clinical trials.

Longevity of Thai physicians: phase 2 and policy implications.

This is Phase 2 of the authors study on long-lived Thai physicians. After obtaining quantitative data from Phase 1, the authors approached 11 male and 5 female physicians whose ages were older than general population's life expectancy. The authors conducted an in-depth interview using semi-structured questions asking about their life, work, lifestyle, and relevant factors. Then the authors synthesized the factors influencing longevity. The authors found that they are genetic, financial stability/security, trying to be disease-free by increasing positive lifestyle (such as exercise) and decrease negative lifestyle (such as drug addict, alcohol consumption), mind-set to be non-attachment (either doing nothing or busy doing everything), and being mentally ready to die. The authors also proposed policy implications for Thai physicians and people accordingly.