Objective To evaluate the analytical variables of the reversed-phase high pressure liquid chromatography (HPLC) with 5-Fluorouracil(5-Fu) as an internal standard for determining creatinine in human serum and urine. The method was used as a candidate reference method for accuracy assessment of routine creatinine test kits.Methods We tested the accuracy, precision, linearity of the reversed-phase HPLC.We analyzed split samples of a panel of 85 patients’ serum and 94 patients’ urine and compared the results of the routine test kits and HPLC by means of bias plots (percentage differences of results) and standard linear regression.Results The linear range of HPLC method was up to 2 210 ?mol/L, the within-run CV(n=5) was below 2.5% and the between-day CV(n=10) was less than 4.5%. The analytical recovery rate was 96.3%～102.4%. All of the test kits correlated very well with HPLC.Conclusions We recommend the reversed-phase HPLC with 5-Fu as an internal standard as a candidate reference method for determining creatinine in human serum and urine.The enzymatic method with creatininase coupled sarcosine oxidase is suitable for routine work in clinical laboratories.

Glycated hemoglobin is internationally recognized as the gold standard for assessment of long-term glycemic status in diabetic patients,but our determination of glycosylated hemoglobin standardization work is still at primary stage at present.Consistency and accuracy of glycated hemoglobin results are still needed to be solved.

A modified dye test with microplate was to be established to detect Toxoplasma antibodies with cell-cultured Toxoplasma gondii. Numbers of stained and unstained tachyzoites were estimated in every 100 tachyzoites in each well after dyeing with methylene blue. The dilution with 50% tachyzoites stained was used as final dilution. Better results of the microplate dye test has been received when the concentration of tachyzoites in suspension reaches 109/ml with 1% sodium citrate as accessory factor.

Objective To investigate the measurement of serum calcium by flame atomic absorption spectrometry (FAAS) and to validate the method for use as a candidate reference method. Methods Serum was diluted by 50 fold with 50 mmol/L hydrochloric acid containing 10 mmol/L LaCl3 and analyzed for calcium on an AA 6800 atomic absorption spectrophotometer. Dilution solutions and FAAS conditions were optimized and the performance of the method was evaluated. Results The method showed within-run, between-run and total CVs of 0. 31%～0.38%, 0.16%～0.30% and 0.35%～0.49%, respectively, and analytical recoveries ranging 98.9%～101.1%. No significant interferences were detected. Conclusions A FAAS method for the measurement of serum calcium has been established. The method is simple and accurate and may be used as a candidate reference method for serum calcium.

Objective To investigate the precision and trueness of results from six imported commercial systems for measurement of gamma-glutamyltransferase (GGT) in serum in order to provide reference for the clinical laboratories to verify the target accuracy. Methods Five fresh frozen human serum samples that differed in catalytic concentration were analyzed in two candidate domestic reference laboratories and the target values for GGT were assigned using IFCC reference measurement procedure. The same samples were tested by six commercial systems which were calibrated using the matched calibrator. Each system consisted of five instruments in five laboratories, which had been well maintained before measurement. The data was collected. Precision from the same manufacturer and different manufacturers and biases between target values and mean values from each system were calculated. Results The differences of the mean values for five levels of commercial systems varied from 16. 1% to 35.4%. For the five levels, the coefficients of variation (CVs) of the results from all measurement system were from 5.3% to 8. 8% , and CVs from each level were A 2. 17%- 5.07%, B 4. 21%-10. 98%, C 0. 52%-2. 38%, D 1.35%-2. 59%, E 0. 23%-1..54%-), F 1.83%-2. 38%. Biases between the mean values of each commercial systems and the target values were A 0. 43% -8.41% ), B -1.49% - -13.04% ), C 11.20% -17.73% ), D 0. 19% -4. 62% ), E -0. 30% - -2. 63% ), F 4). 46%-7.90%, respectively. The investigation showed that biases of two manufacturers were less than a quarter of the total allowable error (TAE) of The Clinical Laboratory Improvement Amendments of 1988 (CLIA'88) in the whole range of investigated concentrations and the other two manufacturers' biases could meet a quarter of TAE in a relative limited range. The biases of two manufacturers were near or more than half of TAE in most levels. It also revealed that the biases of more than half of manufacturers were more than a quarter of TAE in the low or high level of investigated concentrations. Conclusions The mean values of each manufacturer were significantly different. The variances of commercial systems from different manufacturers were much higher than those from the same manufacturer. Some imported commercial systems for measurement GGT should be better calibrated with the reference method, especially in the whole measurement linearity.

Objective To investigate the effect of ischemic post-conditioning (IPO) on the level of Heme oxygenase-1 (HO-1) in acute ischemia - reperfusion (I/R) injury of lung in order to illuminate its protective mechanism.Methods Forty-eight adult SD rats were randomly divided (random number) into 6groups ( n =8 each):sham operation group ( S group) ; I/R group in which the hilum of left lung was clamped for 45 min followed by 105 min reperfusion; IPO group in which left lung hilum was clamped for 45min and post - conditioned by alternation of 30 s reperfusion with 30 s re-occlusion for three times before perfect perfusion for 102 min; Hemin (HM) + I/R group; ZnPPⅨ (zinc protoporphyrin Ⅸ) + IPO group and HM + S group.Arterial partial pressure of oxygen ( PaO2 ) and malondialdehyde (MDA) content in blood serum were assayed.The left lung was removed for determination of wet/dry (W/D) lung weight ratio and level of HO-1 protein was detected by immunohistochemical technique and pathohistological changes were observed under light microscopic examination. Comparisons among multiple groups were studied by using one-way analysis of variance (ANOVA). Statistical comparisons within groups were analyzed by using paired t -test.Results The level of HO-1 in lung tissue was significantly increased in the I/R group compared with the S group and the HM + S group (P ＜0.01,P ＜0.05).Compared to the I/R group,the IPO and the HM + I/R groups had significant higher level of HO-1 ( P ＜ 0.05,P ＜ 0.01 ).The PaO2 was significantly lower in all experimental groups than that in the S group (90 ± 11 ) mmHg.However,the values of PaO2 in the IPO and the HM + I/R groups were higher than that in the I/R group (P ＜ 0.01 ).In addition to severe lung tissue damage evidenced by pathohistological changes,the lung wet/dry (W/D) weight ratio and MDA level in blood serum were significantly higher in the I/R group than those in the S group (P ＜0.01 ),whereas the lung damage was attenuated either by IPO or by HM pretreatment (P ＜ 0.05,IPO or HM + I/R vs.I/R).Conclusions IPO can attenuate the lung ischemia - reperfusion injury through upregulating the level of HO-1 protein and inhibiting lipid peroxidation injury.

Objective To analyze the causes and treatment methods of early complications after central systemic-pulmonary shunt in complex cyanotic congenital heart diseases.Methods Two hundred and twelve cases of central systemic-pulmonary shunt in complex cyanotic congenital heart diseases were retro-spectively analyzed in order to explore the early postoperative complications and related treatment measures. Results There were 61 cases(28.77%)of the early postoperative complications,including severe low car-diac output syndrome in 27 cases,acute pulmonary edema in 14 cases,24 h shunt pipe blockage in 12 cases, and supraventricular tachycardia in 8 cases.All patients got followed up,average for(2.49 ±1.21 )years.Af-ter the systemic-to-pulmonary artery shunts,pulmonary vascular had significant growth,8 patients(3.77%) of them who pulmonary hypoplasia were promoted by transcatheter aortopulmonary collateral vessels.At the end of the follow-up,77 patients(36.32%)achieved the standard of radical surgery.Conclusion The factors affecting surgical survival rate include:enhancement of patients cardiac function and strictly handle operation indication before operation a clear operational view;rational surgical methods;treatment of complication with-out delay;strict,intensive care and synthesized treatment.

BACKGROUND:The treatment of pulmonary hypertension secondary to congenital heart disease has been a hot topic in the clinical research on cardiac surgery. Although traditional drugs for reducing pulmonary hypertension have excelent effects, there are some defaults, such as difficult monitoring and rebounding phenomenon after drug withdrawal. The traditional heart dacron graft is prone to cause complications, such as deformation, thrombosis, embolism, hemolysis and infection. OBJECTIVE:To investigate the effect of glutaraldehyde-fixed bovine pericardium patch and aerosolized iloprost in patients with pulmonary hypertension secondary to congenital heart disease. METHODS:Ninety patients with pulmonary hypertension due to congenital heart disease underwent a surgery. Glutaraldehyde-treated bovine pericardium patch were used to repair cardiac septal defect, and then aerosolized iloprost was applied after operation, administered for 3 days according to 30 ng/min/kg, every 4 hours in the first 12 hours of a day, and every 6 hours in the resting 12 hours. Mean arterial pressure, mean pulmonary arterial pressure, systemic vascular resistance index, pulmonary vascular resistance index were recorded before inhalation, immediately after inhalation, and 30 minutes after inhalation. The pericardium-associated complications, and cardiac function were also observed at folow-ups. RESULTS AND CONCLUSION: The involved 90 cases were detected by echocardiography. The results showed that, al the flaps were closed, there was no shunting or echo discontinuation of atrial septum. The heart contraction function was normal. No pericardium-associated complications were found. There was no significant difference in the mean arterial pressure and systemic vascular resistance index in al patients at different time points. The mean pulmonary arterial pressure and pulmonary vascular resistance index immediately after inhalation were significantly lower than that before inhalation (P < 0.01). The decrease was also significant 30 minutes after inhalation (P < 0.05). The intervention of glutaraldehyde-fixed bovine pericardium patch and aerosolized iloprost is safe and effective to treat patients with pulmonary hypertension secondary to congenital heart disease.

Objective To prepare the frozen human serum pools for AFP reference materials through quantity value transmission from several analysis systems . Methods Method establishment. According to the requirement of preparation for the national standard materials , the studies of homogeneity and stability of frozen human serum pools for AFP reference materials were carried out .The commutability of prepared AFP reference materials and WHO AFP 72/225 reference material were assessed .By use of four automated chemiluminescence analysis systems , the prepared reference materials and different dilutions of WHO reference material 72/225 were tested in the same run.The values of prepared AFP reference materials were assigned by comparing these results and the uncertainty was evaluated .Results The three levels of AFP reference materials were tested to be homogeneous .The long term stability had been observed at -80℃for 14 months.The different dilutions of WHO AFP 72/225 reference material and three levels of prepared reference materials were commutable with patient serum samples among the four analysis systems .Through multiple system quantity value transmission and total uncertainty evaluation , the assigned values ( IU/ml) of three levels of AFP reference materials were 23.0 ±3.0, 93.2 ±7.2, ( 26.1 ±2.4 ) ×102 respectively.Conclusions The three levels of AFP reference materials were homogeneous and stable in accordance with requirement of preparation for national standard materials .The assigned values were reliable.The materials showed accepted commutability across 4 analytical systems.These materials had been approved as the national certified reference materials .These reference materials could be applied for the calibration or calibration verification of clinical analytical systems and the external quality assessment schemes for clinical laboratories.

Objective: To investigate the inlfuence of angiotensin converting enzyme 2 (ACE2) on lectin-like oxidized low density lipoprotein receptor-1 (LOX-1) protein expression and to explore the protective effect of ACE2 on vascular endothelial cells. Methods: Our work includedin vitro andin vivo studies. For in vitro experiment, the human umbilical vein endothelial cell (HUVEC) were cultured and transfected with replication deficient recombinant adenovirus of ACE2 (Ad-ACE2), and LOX-1 protein expression stimulated by angiotensin 2 was examined by Western blot analysis. Forin vivo study, atherosclerosis plaques were induced in 20 apolipoprotein E-deifcient (ApoE-/-) mice, and then randomly divided them into 2 groups: ACE2 group, the mice received Ad-ACE2 (2.5×109 pfu/ml) injection through caudal vein, EGFP (enhanced green lfuorescent protein) group, the mice received equal replication deifcient recombinant adenovirus of EGFP (Ad-EGFP) injection through caudal vein.n=10 in each group. The animals were executed after 1 month treatment to collect abdominal aorta. Lipid content in atherosclerosis plaque was evaluated by Oil red O staining and LOX-1 protein expression was examined by immunohistochemistry and Western blot analysis. Results: Bothin vitro andin vivo experiments conifrmed that endothelial cell LOX-1 protein expression was signiifcantly inhibited by ACE2 transfection. The lipid content in ACE2 group was obviously lower than that in EGFP group byin vivo study. Conclusion: ACE2 may inhibit LOX-1 protein expression and therefore reduce the progress of atherosclerosis.