Application of mixture analysis methods in association between metals mixture exposure and DNA oxidative damage / 中华预防医学杂志

Objectives: To study the association between metals mixture exposure and DNA oxidative damage using mixture analysis methods, and to explore the most significant exposure factors that cause DNA oxidative damage. Methods: Workers from steel enterprises were recruited in Shandong Province. Urinary metals were measured by using the inductively coupled plasma mass spectrometry method. The level of urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) was determined by using the ultra-high performance liquid chromatography-mass spectrometry method. Bayesian kernel machine regression (BKMR), elastic net regression and quantile g-computation regression were used to analyze the association between urinary metals and urinary 8-OHdG. Results: A total of 768 subjects aged (36.15±7.40) years old were included in the study. BKMR, elastic net regression and quantile g-computation all revealed an overall positive association between the mixture concentration and increased urinary 8-OHdG. The quantile g-computation results showed that with a 25% increase in metal mixtures, the urinary 8-OHdG level increased by 77.60%. The elastic net regression showed that with a 25% increase in exposure risk score, the urinary 8-OHdG level increased by 26%. The BKMR summarized the contribution of individual exposures to the response, and selenium, zinc, and nickel were significant contributors to the urinary 8-OHdG elevation. Conclusion: Exposure to mixed metals causes elevated levels of DNA oxidative damage, and selenium, zinc, and nickel are significant exposure factors.

Predictive values of serum 8-hydroxydeoxyguanosine on disease progression and prognosis of patients with sepsis / 中华烧伤杂志

Objective: To investigate the values of serum 8-hydroxydeoxyguanosine (8-OHdG) in predicting disease progression and prognosis of patients with sepsis. Methods: The prospective observational research methods were used. A total of 124 patients with sepsis who met the inclusion criteria were admitted to the Department of Emergency of the First Affiliated Hospital of Wenzhou Medical University from April 2015 to July 2016, including 79 males and 45 females, aged (62±15) years. The sepsis-related organ failure assessment (SOFA) scores of all patients on admission and on the second day of admission and their difference (ΔSOFA) were calculated. The patients were divided into non-progression group with ΔSOFA score <2 (n=101) and progression group with ΔSOFA score ≥2 (n=23), and according to the survival during hospitalization, the patients were divided into survival group (n=85) and death group (n=39). Data of patients between non-progression group and progression group, survival group and death group were compared, including the gender, age, days in emergency intensive care unit (ICU), smoking, hypertension, diabetes mellitus, serum white blood cell count, serum C-reactive protein, and serum procalcitonin on admission, and serum 8-OHdG within 24 h of admission. The multivariate logistic regression analysis was used to screen the independent risk factors of disease progression and death during hospitalization in 124 patients with sepsis, the receiver's operating characteristic (ROC) curves were drawn according to the independent risk factors, and the area under the curve (AUC), the best threshold, and the sensitivity and specificity under the best threshold were calculated. The patients were divided into high 8-OHdG group (n=35) and low 8-OHdG group (n=89) according to the best threshold in ROC curve of death during hospitalization. The data including the gender, age, SOFA score on admission, SOFA score on the second day of admission, and ΔSOFA score of patients in the two groups were compared. The survival rates of patients within 90 d of admission in the two groups were compared by the Kaplan-Meier method. Data were statistically analyzed with independent sample t test, Mann-Whitney U test, chi-square test, and Log-rank test. Results: The gender, age, days in emergency ICU, smoking, complicated with hypertension, complicated with diabetes mellitus, serum white blood cell count, serum C-reactive protein, and serum procalcitonin on admission of patients in non-progression group and progression group were similar (P>0.05). The serum 8-OHdG within 24 h of admission of patients in progression group was significantly higher than that in non-progression group (Z=-2.31, P<0.05). Multivariate logistic regression analysis showed that the serum 8-OHdG within 24 h of admission was the independent risk factor for disease progression of 124 patients with sepsis (odds ratio=1.06, with 95% confidence interval of 1.01-1.11, P<0.05). The AUC under the ROC curve of serum 8-OHdG within 24 h of admission to predict disease progression of 124 patients with sepsis was 0.65 (with 95% confidence interval of 0.52-0.79, P<0.05), the optimal threshold was 32.88 ng/mL, and the sensitivity and specificity under the optimal threshold was 52.2% and 79.2%, respectively. The gender, age, days in emergency ICU, smoking, complicated with hypertension, complicated with diabetes mellitus, and serum white blood cell count, serum C-reactive protein, and serum procalcitonin on admission of patients in survival group and death group were similar (P>0.05). The serum 8-OHdG within 24 h of admission of patients in death group was significantly higher than that in survival group (Z=-2.37, P<0.05). Multivariate logistic regression analysis showed that the serum 8-OHdG within 24 h of admission was the independent risk factor for death of 124 patients with sepsis (odd ratio=1.04, with 95% confidence interval of 1.00-1.09, P<0.05). The AUC under the ROC curve of serum 8-OHdG within 24 h of admission to predict death of patients during hospitalization was 0.63 (with 95% confidence interval of 0.52-0.75, P<0.05), the optimal threshold was 32.43 ng/mL, the sensitivity and specificity under the optimal threshold was 51.3% and 84.7%, respectively. The gender and age of patients in high 8-OHdG group and low 8-OHdG group were similar (P>0.05). The SOFA score on admission, SOFA score on the second day of admission, and ΔSOFA score of patients in high 8-OHdG group were significantly higher than those in low 8-OHdG group (with Z values of -2.49, -3.01, and -2.64, respectively, P<0.05 or P<0.01). The survival rate within 90 d of admission of patients in low 8-OHdG group was significantly higher than that in high 8-OHdG group (χ2=14.57, P<0.01). Conclusions: Serum 8-OHdG level is an independent risk factor for disease progression and death in sepsis patients with limited ability for predicting disease progression and prognosis of sepsis of patients. The patients with higher serum 8-OHdG level have higher death risk within 90 d of admission.

Development of a colloidal gold based immunochromatographic strip for 8-OHdG detection / 生物工程学报

8-hydroxy-2'-deoxyguanosine (8-OHdG) is a sensitive and stable biomarker for evaluating DNA oxidative damage. A rapid and sensitive colloidal gold immunochromatographic strip was developed for 8-OHdG detection by a competitive method. The sample pad (glass cellulose film), bonding pad (glass cellulose film), nitrocellulose film and absorbent pad were pasted on the polyvinyl chloride (PVC) base plate to construct the test strip. Colloidal gold (AuNPs) was prepared by the reduction of chloroauric acid with sodium citrate. 8-OHdG antibody (Ab) was coated on the outer layer of AuNPs to form Ab@AuNPs as a probe. Bovine serum albumin (BSA) and 8-OHdG were conjugated with carbodiimide hydrochloride to prepare an artificial antigen, which was used as the coating antigen of detection line. Goat anti mouse polyclonal antibody IgG was used as the coating antibody of control line. The experimental parameters were optimized including the type of nitrocellulose membrane, the formula of loading solution, and the spraying amount of gold labeled antibody. The results showed that the appropriate nitrocellulose membrane was CN 95. The optimal loading solution included BSA (1%), Tween-20 (3%), sucrose (3%) and NaCl (0.9%). The optimal spraying amount of gold labeled antibody was 4 μL. 8-OHdG can be detected by the strip under visible light, and the level of 8-OHdG in urine can be preliminarily determined by comparing the color intensity of T line and C line. The 8-OHdG concentration in urine was further calculated by the gray value of T line and the threshold of detection was 2.55 μg/L. This colloidal gold immunochromatographic strip is simple, rapid and specific for detecting 8-OHdG in human urine to preliminarily evaluate the human status.

Sperm DNA oxidative damage in patients with idiopathic asthenozoospermia / 中南大学学报(医学版)

OBJECTIVE@#To discuss seminal plasma oxidative stress and sperm DNA oxidative damage in patients with idiopathic asthenozoospermia.@*METHODS@#Infertile couples were selected from the clinic outpatients of the Reproductive Center of Xiangya Hospital, Central-South University from December 2010 to March 2011. Fresh semen of 28 men with idiopathic asthenozoospermia was collected as an experiment group, and 24 fertile men with normal semen and normal reproductive history served as a control group. Level of reactive oxygen species (ROS) in the seminal plasma was assessed with luminer chemiluminescence method. Density of sperm DNA oxidation product 8-hydroxy-2'-deoxyguanosine (8-OHdG) was assessed with enzyme linked immunosorbent assay.@*RESULTS@#1) ROS level in the experiment group was higher than that in the control group (P<0.01). There was negative correlation between the percentage of progressive motility spermatozoa and the ROS level in the seminal plasma in the 2 groups (r=-0.72, P<0.01). 2) Density of sperm 8-OHdG in the experiment group was higher than that in the control group (P<0.01). There was negative correlation between the percentage of progressive motility spermatozoa and the density of sperm 8-OHdG (r=-0.73, P<0.01). 3) There was positive correlation between the ROS level in the seminal plasma and the density of sperm 8-OHdG (r=0.77, P<0.01).@*CONCLUSION@#There is sperm DNA oxidative damage in patients with idiopathic asthenozoospermia, which may be related with the oxidative stress. Excessive generation of reactive oxygen species may be a cause of low sperm motility in patients with idiopathic asthenozoospermia.