ABSTRACT
ObjectiveTo investigate the clinical appropriateness and application value of the peroxidase （POD） method for the detection of unbound bilirubin （UB） in neonatal serum. MethodsHydrogen peroxide （0.33 mol/L） and three different final concentrations （0.019， 0.038， 0.075 μg/mL） of horseradish peroxidase （HRP） were added to standard bilirubin solution （1， 2， 3 μmol/L） to obtain a standardized HRP primary rate constant Kp. Then 25 μL of neonatal serum was diluted by 41.6 fold， and measured with 2.4 and 4.8 μg/mL HRP at 37 ℃ under the dark， to determine the UB concentration. The accuracy， precision， and stability of the methodology were validated. The clinical characteristics of 33 jaundiced neonates were collected， including total serum bilirubin （TSB）， indirect bilirubin （IDB）， albumin （ALB）， bilirubin to albumin molar ratio （BAMR）， etc. The experimental data were analyzed by Graphpad Prism 8.0. ResultsA standardized Kp of （7.20±1.08） mL·μg-1·min-1 was determined at pH 7.4±0.2， 37 ℃ in the dark. The HRP activity and UB concentrations remained stable at -20 ℃ for 3 weeks and a week， respectively. The mean intra-day and inter-day coefficients of variation of the serum samples with different UB concentrations were less than 10%. In this study， the UB concentrations in 33 jaundiced neonates （gestational age ≥35 weeks） were measured by the POD method in the range of （0.32～1.20） μg/dL， which was positively correlated with TSB， IDB and BAMR. Of the five infants whose UB concentrations measured more than 1 μg/dL， three received intensive phototherapy （60%）. ConclusionsThe POD method combined with a standard equipment spectrophotometer to detect serum UB concentrations in neonates is easy to operate， rapid to detect， and low cost. This method has good accuracy and precision， which is convenient for clinical implementation. Moreover， the measurement of serum UB may assist us in better management of neonatal jaundice in clinical practice.
ABSTRACT
Objective: To establish an ultrahigh performance liquid chromatography tandem mass spectrometry method for the determination of creatinine (Cre) and 2-thiothiazolidine-4-carboxylic acid (TTCA) in urine. Methods: In October 2020, the end-of-shift urine samples of the monitored subjects were taken, and the filtrate was prepared by centrifugation. After separated by ultra high performance liquid chromatography C18 column, acetonitrile and 0.2% acetic acid aqueous solution were used as mobile phases for gradient elution, the three quadrupole tandem mass spectrometry adopted an electrospray ion source (ESI) , the ion source temperature was 500 ℃ , and the air curtain gas flow rate was 31.4 L/min, qualitative and quantitative analysis of Cre and TTCA were carried out under the multiple reaction monitoring mode. Results: The linear range of Cre was 1.0-1 000.0 μg/L, the linear equation was y=947.3x-1605.6, and the correlation coefficient was 0.9994. The detection limit and the limit of quantitation were 0.3, 1.0 μg/L. When the addition concentrations were 50.0, 150.0 and 450.0 μg/L, the recovery rates were 92.8%-94.6% , the intra assay precisions were 3.6%-5.7% , and the inter assay precisions were 3.4%-5.4%. The linear range of TTCA was 0.1-200.0 μg/L, the linear equation was y=1164.7x-2243.9, and the correlation coefficient was 0.9991. The detection limit and the limit of quantitation were 0.03, 0.1 μg/L. When the addition concentrations were 10.0, 40.0 and 160.0 μg/L, the recovery rates were 90.8%-93.6%, the intra assay precisions were 4.6%-7.4%, and the inter assay precisions were 4.4%-6.9%. Conclusion: The sample pretreatment process of the ultra high performance liquid chromatography tandem mass spectrometry method for the determination of Cre and TTCA in urine is simple, and the continuous determination of Cre and TTCA in urine can be realized only by switching mass spectrometry parameters under the same chromatographic conditions, which is accurate and efficient, and each performance index of the method meets the determination requirements.
Subject(s)
Humans , Chromatography, High Pressure Liquid , Creatinine , Tandem Mass Spectrometry , ThiazolidinesABSTRACT
OBJECTIVE: To estimate the biological dose by the chromosome aberration analysis in a victim suffered in the radioactive source-loss accident in Nanjing City. METHODS: Peripheral blood sample of the victim was collected 6 days after radioactive exposure. Individual radioactive biological dose was estimated by identifying the aberration of the dicentrics plus centric rings in the metaphase chromosome of cells. The distribution of chromosome aberration was tested by the Poisson distribution. Impure Poisson distribution was used to estimate the radiation dose. RESULTS: Among the 353 cells observed at metaphase,75 aberration of dicentrics plus centric rings were found,43 cells had 1 aberration and 7 cells had 2 aberrations. Moreover,there were 3 multi-aberration cells with 3,4 and 11 aberrations respectively. The average individual radiation dose was estimated to be 1. 52 Gy,which was consistent with the clinical diagnosis as mild acute bone marrow radiation disease. The Poisson distribution u test revealed that the patient suffered from nonhomogeneous radiation.By the impure Poisson distribution test,the radiation exposure proportion of the whole body was estimated to be 55% and the average dose was 3. 02 Gy. CONCLUSION: The biological dose estimation was successfully performed,the results showed that this was a case of nonhomogeneous irradiation.