An electrochemical biosensor for the detection of aflatoxin B1 based on the specific aptamer and HCR biological magnification.

Aflatoxin B1 (AFB1) is a highly toxic mycotoxin, which causes severe acute or cumulative poisoning. Therefore, it is important to develop sensitive and selective detection methods for AFB1 for the safety of food and medicinal herbs. Herein, we have developed a "signal-on" electrochemical aptasensor based on the high specificity of the aptamer and hybridization chain reaction (HCR) biological amplification for AFB1 detection. In this work, thiol-modified complementary DNA (cDNA) immobilized on the surface of a gold electrode (GE) served as an initiator DNA. When AFB1 was present, it competed with the cDNA for binding to the aptamers, which resulted in the detaching of aptamers from the cDNA-aptamer duplexes. Then, the single-stranded cDNA acted as an initiator to trigger the HCR signal amplification. Therefore, long double-stranded DNA (dsDNA) products were produced, which could load large amounts of methylene blue (MB) molecules to generate a distinct electrochemical signal. Under the optimized conditions, the proposed electrochemical aptasensor achieved the ultrasensitive detection of AFB1 with a linear detection range of 0.01-100 pg mL-1, and a limit of detection (LOD) down to 2.84 fg mL-1. Furthermore, the electrochemical aptasensor was successfully applied for detecting AFB1 in corn and two kinds of traditional Chinese medicine samples, indicating the potential value for AFB1 detection in practical samples.

Visual detection of aflatoxin B1 based on specific aptamer recognition combining with triple amplification strategy.

A highly sensitive and specific visual detection method for aflatoxin B1 (AFB1) based on the target specificity of aptamer, rolling circle amplification (RCA) and enzyme catalysis biological amplification effect has been established. In this work, AFB1 aptamer immobilized on the surface of magnetic beads (MB) serves as a molecular recognition probe. In the absence of AFB1, the aptamer and auxiliary linking probe (LP) maintain a double stranded state due to partial base pair complementarities. By contrast, in the presence of AFB1, the aptamer preferentially binds to AFB1 specifically, and the LP later restores to a single stranded state. Subsequently, the RCA reaction is triggered by above-mentioned single stranded LP to generate long DNA strands, which are employed to capture amounts of signal probes (SP) and horse radish peroxidases (HRP). Finally, amounts of HRP catalyze the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) by H2O2 and leads to a dramatic color change of the solution from colorlessness to deep blue as a signal indicator, obtaining a high sensitivity, high specificity and visual detection of AFB1. Under optimal conditions, a good linear detection range (0.5-40 pg·mL-1) was achieved, and the limit of detection (LOD) was 0.13 pg·mL-1. Besides, the proposed aptasensor showed excellent specificity for AFB1 compared with five other mycotoxins. More than that, all reactions occur on the surface of the magnetic beads, which not only facilitates the detection operation process including the efficient isolation and collection of AFB1 from sample matrix, but also gets better selectivity and stronger resistibility to target analyte in complex sample matrix, adequately indicating its potential application in AFB1 practical detection.

Effect of Lidocaine Pre-Treatment on Protamine-Induced Pulmonary Vascular Reaction During the Repair of Congenital Heart Disease.

BACKGROUND: Protamine is a polycationic, and a strong basic peptide isolated from Clupeidae or Salmonidae fishes' sperm, which is rich in arginine and highly alkaline. OBJECTIVE: To explore the effect of lidocaine pre-treatment on protamine-induced pulmonary vascular reaction during the repair of congenital heart disease. METHODS: Eighty patients undergoing repair of congenital heart disease were randomly divided into four groups: A1 (non-pulmonary hypertension + lidocaine pre-treatment) group, A2 (non-pulmonary hypertension + normal saline) group, B1 (pulmonary hypertension + lidocaine pre-treatment) group, and B2 (pulmonary hypertension + normal saline) group. Hemodynamic parameters, pulmonary inflammation, and pulmonary function were assessed at six intraoperative time points, two intraoperative time points and three intraoperative time points, respectively. P-value <0.05 was considered statistically significant. RESULTS: A2 group exhibited increased PAP, Paw, RI and A-aDO2. B2 group exhibited increased Paw, RI and A-aDO2 and decreased Cydn and OI after protamine administration. These changes were not observed in A1 and B1 group. Compared with A1 and B1 groups, plasma TXB2 level in A2 and B2 group was higher, but 6-keto-PGF1a in A2 and B2 groups was lower. Incidence of protamine adverse reactions in A1 and B1 group was lower than that in A2 and B2 group. CONCLUSION: Precondition of lidocaine before neutralization of heparin may be effective for protamine-induced pulmonary vascular reaction during CHD repair.

Effect of perfusate oxygenation on inflammatory response in congenital heart disease children from low versus high altitude.

OBJECTIVE: To examine the altitude differences in the optimal perfusate oxygenation (PpO2) in patients who underwent cardiac surgery. METHODS: We included children (aged 1 month to 18 years) with congenital heart diseases surgically repaired between 2012 and 2018. We included only patients who underwent cardiac surgery with arrested heart cardiopulmonary bypass. Primary outcome was severe systemic inflammatory response syndrome (SIRS). Logistic regression was used to evaluate the association between arterial PpO2 on continuous and categorical scales and severe SIRS by altitude. We established PpO2 thresholds that equated to a risk probability of roughly 0.185 or greater for developing severe SIRS in each group of altitude. RESULTS: Among 3918 patients from low altitudes and 2384 from high altitudes, high-altitude patients were older (median, 42.3 [interquartile range 22.8-75.8] vs 37.1 [17.7-69.1] months, P < .001) and had lower arterial PpO2 (289 [237-342] vs 301 [246-362] mm Hg, P < .001). Greater PpO2 was associated with increased risk of severe SIRS overall (adjusted odds ratio, 1.221 [95% confidence interval, 1.167-1.278] per standard deviation increase), with a stronger monotonic associations for low-altitude patients than for high-altitude patients (adjusted odds ratio, 1.302 [95% confidence interval, 1.229-1.379] vs adjusted odds ratio, 1.083 [95% confidence interval, 1.003-1.170] per standard deviation increase) (Pinteraction = .0003). A PpO2 level of 310 mm Hg identified low-altitude patients with a risk probability of roughly 0.185 or greater of severe SIRS, whereas the cutoffs ranged from 200 mm Hg to 325 mm Hg for high-altitude patients. CONCLUSIONS: This study suggests altitude differences in the association of arterial PpO2 with inflammatory response following pediatric cardiac surgery.

Occupational, Transport, Leisure-Time, and Overall Sedentary Behaviors and Their Associations with the Risk of Cardiovascular Disease among High-Tech Company Employees.

This study examined the associations of overall and domain-specific (i.e., occupational, transport, and leisure-time) sedentary behaviors with cardiovascular disease (CVD) risk factors among high-tech company employees in Taiwan. A total of 363 participants employed at high-tech companies (mean age ± standard deviation: 37.4 ± 7.2 years) completed a questionnaire administered by email regarding their overall, occupational, transport, and leisure-time sedentary behaviors. Self-reported data of height and weight, blood pressure, blood sugar, and total cholesterol levels were also collected in 2018. An adjusted binary logistic regression model was employed in the analysis. After adjusting for sociodemographic variables, high-tech company employees who used a computer (or Internet) for more than 2 h per day during their leisure time were more likely to have CVD risk factors (odds ratio: 1.80; 95% confidence interval: 1.08-3.00). No significant associations with CVD risk factors were detected for total sedentary time, occupational sitting, television viewing time, and transport-related sitting. Despite the nature of cross-sectional design in this study, our findings may have considerable implications for intervention designers and policymakers of Taiwan. Developing effective strategies for limiting leisure-time computer use should be considered for the prevention of CVD among high-tech company employees.