OBJECTIVE To investigate the reasons of pediatric nosocomial infection,analyze the possible risk factors,and provide the effective control and prevention strategies. METHODS A total of 18002 patients were investigated in 2007 by prospective study. The data were analyzed via SPSS 11.5 statistical analysis software using mainly descriptive and contrast analysis. RESULTS The nosocomial infection rate was 2.44%. The children were relatively highly infected on both of age from 1-month-old to 1-year-old (3.67%) and stay in hospital over 10 days (7.85%) ,the season in third and fourth quarters (3.13% and 2.64%). The nosocomial infection occurred mainly in respiratory tract and gastrointestinal tract,and more respiratory infections occurred in winter and spring,but more gastrointestinal tract infections occurred in summer and autumn. CONCLUSIONS Pediatric patients are more easy infected of the baby age or the longer stay in the hospital. Pediatric nosocomial infection more occurrs in the summer and autumn. Hospitals should focus on preventing and controlling the respiratory and gastrointestinal infections.

OBJECTIVE To establish the estimation model for the exposure of mycophenolic acid （MPA） in early renal transplant recipients [calculated by the area under the plasma concentration-time curve with 12 h （AUC0－12 h）]. METHODS Twenty kidney transplant recipients， who received triple immunosuppressive therapy of mycophenolate mofetil （MMF）+tacrolimus+ methylprednisolone， were selected and given MMF dispersible tablets （750 mg， q12 h） on the 15th day after the operation； the blood samples were collected from the patients before and 0.5， 1.0， 1.5， 2.0， 3.0， 4.0， 6.0， 8.0， 12.0 hours after the administration， respectively. The blood concentration of MPA was determined， and the pharmacokinetic parameters of MPA were calculated. The multivariate linear stepwise regression analysis method was used to fit an estimation formula for the finite sampling method suitable for MPA-AUC0－12 h of the recipients. Bland-Altman analysis was used to evaluate the agreement between the estimation formula and the classical pharmacokinetic method. RESULTS The main pharmacokinetic parameters of MPA in 20 renal transplant recipients： c0 was （1.53±0.84） μg/mL， cmax was （12.07±5.97） μg/mL， t1/2 was （5.41±3.67） h， tmax was （1.58±0.75） h， and the average AUC0－12 h calculated by the classical pharmacokinetic method was （33.95±13.40） μg·h/mL. MPA-AUC0－12 h was estimated with sampling points of “4.0， 8.0， 12.0 h”； the simplified calculation formula was AUC0－12 h＝12.058+2.819c4.0+7.045c8.0+ 3.879c12.0 （R 2＝0.934）. The predicted value had a good correlation and consistency with the measured value， and 95.0% of predicted values did not exceed the x±1.96SD （standard deviation） range. CONCLUSIONS The estimation model is established successfully for the exposure of MPA in early renal transplant recipients； the model has better prediction accuracy and fewer sampling points.