BACKGROUND: 5-fluorouracil (5-Fu) is universally used as an antineoplastic agent in gastrointestinal cancer, but the side effect of it confined further clinical application. OBJECTIVE: To determinate mice plasma concentration curves for 5-Fu and its chitosan (CS)-polyaspartic acid (Pasp) nanoparticles, and to investigate their primary pharrnacokinetics. DESIGN, TIME AND SETTING: Randomization control animal trials were performed in the Department of Gastroenterology, Zhongshan Hospital of Fudan University between October 2006 and June 2007. MATERIALS: Totally 180 female Kunming mice were obtained from the Department of Laboratory Animal, Fudan University. 5-Fu (purity 99%) was purchased from Shanghai Xudong Haipu Pharmaceutical Co, Ltd (Shanghai, China). Two kinds of CS-Pasp-5-Fu particles were offered by Department of Macromolecular Science, Key Laboratory of Molecular Engineering of Polymers of Educational Ministry, Fudan University (Shanghai, China). METHODS: Kunming mice were randomly divided into three groups and each group was administrated with 5-Fu or either type of its CS-Pasp-5-Fu nanoparticlos. The plasma concentrations of 5-Fu were evaluated by high performance liquid chromatography after 15 minutes, 1 hour, 2 hours, 4 hours, 6 hours, 8 hours, 12 hours, 16 hours, 24 hours and 48 hours of the administration. The pharmacokinetic parameters were computed utilizing 3P97. MAIN OUTCOME MEASURES: Relative recovery, absolute recovery and the stability of samples. RESULTS: The peak concentration of 5-Fu group occurred within 15 minutes and then decreased rapidly. The No.1 nanoparticles group's peak concentration occurred 6 hours after the administration and the effective concentration time lasted for about 14 hours. No.2 nanoparticles group's concentration curve was double-apex, the apexes occurred around the 2 hours and 16 hours, the concentration decreased at the 24 hours after the administration. Both of the two kinds of the nanoparticles groups' peak concentration of 5-Fu in plasma are lower than the 5-Fu group, The half-life times were prolonged and the areas under curve were higher. CONCLUSION: Compared to 5-Fu, the CS-Pasp-5-Fu nanoparticles are controlled released.

As a highly prevalent global condition, myopia significantly impacts the ocular health of young individuals in China. Orthokeratology lens, as a rigid corneal contact lens, has demonstrated effective control over the progression of myopia; however, its mechanism of action remains incompletely elucidated. As one of the factors influencing visual acuity, higher-order aberrations will undergo marked changes after orthokeratology, with particular emphasis on the alterations in spherical aberrations and coma. The changes in corneal morphology induced by orthokeratology lead to significant positive increase in both spherical aberration and coma. Furthermore, the elevation of spherical aberration and coma demonstrates a negative correlation with the rate of axial length growth following orthokeratology. The interplay among spherical aberration, coma, defocus, accommodation, astigmatism, and pseudo-accommodation may constitute the underlying mechanism governing the control of myopia through orthokeratology.

Objective To investigate the peripheral retinal defocus and its influencing factors in children and adoles-cents with low to moderate myopia.Methods Totally 281 children and adolescents aged 6-15 years were included in the study,and only the right eye was selected.After cycloplegic refraction as well as axial length(AL)and average corneal curvature(AveK)measurements,the patients were divided into low myopia(LM)group(-3.00 D≤SE≤-0.50 D)and moderate myopia(MM)group(-6.00 D≤SE＜-3.00D)according to spherical equivalent(SE),and stratified compari-sons were made according to AL[AL1 group(23.00 mm≤AL≤24.00 mm),AL2 group(24.00 mm＜AL≤25.00 mm),and AL3 group(25.00 mm＜AL≤26.00 mm)]and AveK[AveK1 group(40.00 D≤ Ave K≤43.00 D)and AveK2 group(43.00 D＜AveK≤46.00 D)].Multispectral refraction tomography was used to measure the refraction difference value(RDV),in-cluding TRDV(0° to 53°),RDV-15(0° to 15°),RDV-30(0° to 30°),RDV-45(0° to 45°),RDV-15-30(15° to 30°),RDV-30-45(30° to 45°),RDV-45-53(45° to 53°),RDV-S(superior),RDV-I(inferior),RDV-T(temporal)and RDV-N(na-sal).The RDV was compared in the groups divided according to SE,AL and AveK individually,and the correlation be-tween RDV and age,SE,AL and AveK was analyzed.Moreover,the factors affecting RDV in all ranges were analyzed by multiple linear regression.Results Compared with the LM group,the MM group had significant increases in TRDV,RDV-30,RDV-45,RDV-15-30,RDV-30-45,RDV-45-53,RDV-S,RDV-I and RDV-N(all P＜0.05)and no significant differ-ence in RDV-15 and RDV-T(both P＞0.05).According to the comparisons of AL groups and AveK groups,the TRDV,RDV-30,RDV-45,RDV-15-30,RDV-30-45,RDV-45-53,RDV-S,RDV-I and RDV-N in the AL2 group were significantly higher than those in the AL1 group(all P＜0.05);the TRDV,RDV-30,RDV-45,RDV-15-30,RDV-30-45,RDV-45-53,RDV-S and RDV-N in the AL3 group were significantly higher than those in AL2 and AL1 groups,and RDV-I and RDV-T in the AL3 group were significantly higher than those in the AL1 group(both P＜0.05);the TRDV,RDV-30,RDV-45,RDV-15-30,RDV-30-45,RDV-45-53,RDV-S,and RDV-I in the Ave K1 group were significantly higher than those in the AveK2 group(all P＜0.05).The correlation analysis showed that TRDV,RDV-45,RDV-30-45,RDV-45-53,RDV-S and RDV-N were positively correlated with age and AL and negatively correlated with SE and Ave K;RDV-30,RDV-15-30 and RDV-I were positively cor-related with AL and negatively correlated with SE and AveK;RDV-T was positively correlated only with AL;RDV-15 was not correlated with age,SE,AL and AveK.Multiple linear regression analysis showed that age was the influencing factor of RDV-45-53 and RDV-S;AL was the influencing factor of TRDV,RDV-30,RDV-45,RDV-15-30,RDV-30-45,RDV-45-53,RDV-S and RDV-T;AveK was the influential factor of RDV-I;SE had no significant effect on RDV in all ranges.Conclu-sion Peripheral retinal defocus in children and adolescents with low to moderate myopia has reached hyperopic defocus,and hyperopic defocus is the least in patients with relatively short AL.Age,AL and AveK can affect peripheral retinal defo-cus in children and adolescents with low to moderate myopia,among which AL is the most important influencing factor.