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 explore the effects of tensile force on vascular lumen formation in three-dimensional printed tissue.Methods:The experimental research method was used. Human umbilical vein endothelial cells (HUVECs) were extracted from discarded umbilical cord tissue of 3 healthy women (aged 22 to 35 years) who gave birth in the Department of Gynaecology and Obstetrics of Suzhou Ruihua Orthopaedic Hospital from September 2020 to May 2021. Human skin fibroblasts (HSFs) were extracted from discarded normal skin tissue of 10 male patients (aged 20 to 45 years) who underwent wound repair in the Department of Hand Surgery of Suzhou Ruihua Orthopaedic Hospital from September 2020 to September 2022. After identification of the two kinds of cells, the 4 th to 6 th passage of cells were taken for the follow-up experiments. HUVECs and HSFs were used as seed cells, and polycaprolactone, gelatin, hyaluronic acid, and fibrin were used as scaffold materials, and the three-dimensional printed vascularized tissue was created by three-dimensional bioprinting technology. The printed tissue with polycaprolactone scaffold of 6 and 10 mm spacing, and without polycaprolactone scaffold were set as 6 mm spacing polycaprolactone group, 10 mm spacing polycaprolactone group, and non-polycaprolactone group, respectively. After 4 days of culture, the printed tissue in 10 mm spacing polycaprolactone group was selected to detect the cell survival by cell viability detection kit, and the cell survival rate was calculated. After 14 days of culture, the printed tissue in three groups were taken, and the shape change of tissue was observed by naked eyes; immunofluorescence staining was performed to observe the arrangement of filamentous actin, and lumen diameter, total length, and number of branches of vessel in the tissue. The tissue with micro-spring structure in the above-mentioned three groups was designed, printed, and cultured for 9 days, and the tensile force applied in the printed tissue was measured according to the force-displacement curve. The number of samples was all 3 in the above experiments. Data were statistically analyzed with one-way analysis of variance and Tukey test. Results:After 4 days of culture, the cell survival rate in printed tissue in 10 mm spacing polycaprolactone group was (91.3±2.2)%. After 14 days of culture, the shape change of printed tissue in non-polycaprolactone group was not obvious, while the shape changes of printed tissue in 6 mm spacing polycaprolactone group and 10 mm spacing polycaprolactone group were obvious. After 14 days of culture, the arrangement of filamentous actin in the printed tissue in non-polycaprolactone group had no specific direction, while the arrangement of filamentous actin in the printed tissue in 6 mm spacing polycaprolactone group and 10 mm spacing polycaprolactone group had a specific direction. After 14 days of culture, The vascular lumen diameters of the printed tissue in 6 mm spacing polycaprolactone group and 10 mm spacing polycaprolactone group were (6.0±1.3) and (10.8±1.3) μm, respectively, which were significantly larger than 0 μm in non-polycaprolactone group ( P<0.05), and the vascular lumen diameter of printed tissue in 10 mm spacing polycaprolactone group was significantly larger than that in 6 mm spacing polycaprolactone group ( P<0.05); the total length and number of branches of blood vessel in the printed tissue in 6 mm spacing polycaprolactone group and 10 mm spacing polycaprolactone group were significantly shorter or less than those in non-polycaprolactone group ( P<0.05), and the total length and number of branches of blood vessel in the printed tissue in 10 mm spacing polycaprolactone group were significantly shorter or less than those in 6 mm spacing polycaprolactone group. After 9 days of culture, the tensile forces applied in the printed tissue in 6 mm spacing polycaprolactone group and 10 mm spacing polycaprolactone group were (2 340±59) and (4 284±538) μN, respectively, which were significantly higher than 0 μN in non-polycaprolactone group ( P<0.05), and the tensile force applied in the printed tissue in 10 mm spacing polycaprolactone group was significantly higher than that in 6 mm spacing polycaprolactone group ( P<0.05). Conclusions:The three-dimensional printed scaffold structure can exert different tensile force in the printed tissue, and the vascular lumen diameter of the printed tissue can be regulated by adjusting the tensile force.

OBJECTIVE To explore and establish an analysis method for sulfamethoxazole blood concentration in patients with heart transplantation to guide clinical rational drug use. METHODS A new two-dimensional liquid chromatograph (2D-LC-UV) based on column switching technology was used. The on-line solid-phase extraction of sulfamethoxazole in serum was performed using a one-dimensional column Aston SC2(3.5 mm×25 mm, 5 μm), then it was intercepted and retained through the middle column Aston SBR(3.5 mm×10 mm, 5 μm), and the target analytes were completely separated and detected by transfer to the second-dimension column Aston SNX4(4.6 mm×130 mm, 5 μm). The chromatographic conditions were obtained by optimization. The one-dimensional mobile phase was acetonitrile-methanol-H2O(10:10:70), the flow rate was 0.8 mL·min-1; the two-dimensional mobile phase ratio was BPI-1 basic mobile phase-API-3 acidic mobile phase-methanol(20:40:40) the flow rate was 1.2 mL·min-1. The UV detection wavelength was 240 nm. RESULTS The correlation coefficient between the concentration of sulfamethoxazole and peak area was in the range of 9.96‒200.04 μg·mL-1 with R2=0.999 6, it showed a good linear relationship. The intra-day and inter-day precisions(RSD) at low, medium and high concentrations were <15%, and the relative recoveries were between 85%‒115%. The blood concentration of 56 patients in the hospital was measured, and only 30 patients(53.57%) had the blood sample sulfamethoxazole concentration of 100‒150 μg·mL-1, and the rest were not comfortable about the concentration treatment window; there were 0 cases of grade III-IV adverse reactions in the urinary system/blood system/liver, etc. CONCLUSION This method has a simple pre-treatment, high automation, can be sampled in large volumes, and has high accuracy and sensitivity. It can meet the requirements of clinical applications. The research results can provide a methodological reference for clinical therapeutic drug monitoring..

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.