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Apurinic/apyrimidinic endonuclease 1 (APE1) exonuclease plays a vital proofreading role in the base excision repair pathway by removing 3’end group, including oxidatively damaged DNA bases, chain terminating nucleotide analog drugs, terminal blocking groups and mismatched bases. Herein, a simple and real time fluorometric method was developed for detecting APE1 exonuclease activity using molecular beacon as substrate. Experimental results demonstrated that the detection limit of this method was 0.01 U/μL for APE1, and the Km value was (0.27 ± 0.10) μmol/L. Moreover, the method was used to screen antibiotics and the results showed that streptomycin sulfate and gentamycin sulfate had a significant inhibitory effect on APE1 exonuclease activity in a concentration-dependent manner. Meanwhile, the assay was used for investigating the inhibitory effects of heavy metal ions on APE1 exonuclease activity. Finally, the method was further used to monitor the effect of heavy metal ions treatment of the APE1 exonuclease activity of ramie, and the results indicated that APE1 exonuclease activity was inhibited in a concentration-dependent manner after treatment with Pb2+ and Cd2+, which was consistent with heavy metal ions assay in vitro. In summary, this method provided an alternative tool for the biochemical analysis for APE1 exonuclease activity, which was hopeful for the assessment for heavy metal ions adsorption according to the enzymatic activity change in phytoremediation.

Arsenic (As) and its compounds are widely used in many applications. Long-term exposure to As can cause acute and chronic poisoning. In severe cases, it can lead to adverse effects, such as gene mutation, cell cancer and fetal malformation. The objective of this study was to accurately estimate As exposure frequency and time. Quantitative analysis of As in single hairs obtained from APL (acute promyelocytic leukemia) patients treated with As2O3 was performed by LA-ICP-MS. An informative As concentration distribution profile of single hair was applied to estimate the As exposure frequency and time. As exposure frequency was estimated according to the number of As concentration peaks. As exposure time was estimated according to the hair growth length in combination with the hair growth rate. The validation results demonstrate that this method was more efficient than the traditional method; compared with the traditional method, which provides estimates in months, our model shortened the As exposure time estimate to the range of a few days, which considerably improved the inference accuracy. Therefore, these results can be used for forensic toxicology studies, environmental exposure monitoring, etc.

As a key regulator of human physiology and metabolic processes, ribonuclease (RNase) A can be used as an important biomarker for predicting human disease occurrence. Hence, establishing sensitive methods for tracking RNase A activity in vitro and in living cells is of great importance. Herein, we present a convenient fluorescence method assisted by reduced graphene oxide (rGO) and DNAzyme mediated fluorescence signal release for RNase A assay. The fluorescence change of the new method showed a positive linear relation with RNase A concentration in the range from 0.5 pg μL−1 to 1 ng μL−1 with a detection limit of 0.089 pg μL−1. By using this method to screen the effector of RNase A from natural compounds, the natural compound of B6 was found to stimulate RNase A activity in vitro and in vivo, the result of which was supported by the real-time imaging of RNase A in living cells. In summary, this fluorescence method with high sensitivity and specificity provides an alternative for RNase A activity assay and effector screening.

Assessing collective drug consumption based on the concentrations of illicit drugs and their metabolites in wastewater is a new technology. Currently, this technology is receiving attention in China, and methods for multiple illicit drug detection in wastewater are urgently needed. In our study, a method with a short runtime (7 min), a small solid-phase extraction (SPE) loading volume (50 mL) and high sensitivity (lower limits of quantitation (LLOQs) ranged from 0.2 to 5 ng/L) was developed for the simultaneous determination of amphetamines, ketamine, opiates, cocaine and their metabolites in wastewater. Samples were enriched by SPE on a mixed-mode sorbent (Oasis MCX) and analyzed by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The limits of detection (LODs) ranged from 0.1 to 2 ng/L, and the LLOQs varied between 0.2 and 5 ng/L. Moreover, the method developed was applied to real wastewater samples collected from 15 different wastewater treatment plants (WWTPs). In the results, the most abundant compounds were morphine (1.8–46.6 ng/L) and codeine (3.7–24.9 ng/L), which were detected in 13 WWTPs. After successful optimization of the UPLC-MS/MS conditions and sample loading pH, the method developed is able to meet the needs of common illicit drug monitoring and high-throughput analysis requirements.

The clinical role of perioperative respiratory muscle training (RMT), including inspiratory muscle training (IMT) and expiratory muscle training (EMT) in patients undergoing pulmonary surgery remains unclear up to now.To evaluate whether perioperative RMT is effective in improving postoperative outcomes such as the respiratory muscle strength and physical activity level of patients receiving lung surgery.The PubMed, EMBASE (Seven studies involving 240 participants were included in this systematic review and meta-analysis. Among them, four studies focused on IMT and the other three studies focused on RMT, one of which included IMT, EMT and also combined RMT (IMT-EMT-RMT). Three studies applied the intervention postoperative, one study preoperative and the other three studies included both pre- and postoperative training. For primary outcomes, the pooled results indicated that perioperative RMT improved the postoperative MIP (mean = 8.13 cmHPerioperative RMT enhanced postoperative respiratory muscle strength and physical activity level of patients receiving lung surgery. However, RCTs with large samples are needed to evaluate effects of perioperative RMT on postoperative outcomes in patients undergoing lung surgery.

The measurement of illicit drugs in wastewater is increasingly being adopted as a method for objective monitoring of population-level illicit drug use. This work describes the first small-volume direct-injection ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for the simultaneous determination of 11 illicit drugs and metabolites in wastewater. The method required an injection volume of only 30 µL of wastewater sample, the limits of detection (LOD) ranged from 0.4 ng/L to 2 ng/L and the lower limits of quantitation (LLOQ) ranged from 1 ng/L to 5 ng/L. Application of the method to real wastewater samples collected from wastewater treatment plants revealed morphine in all samples, together with other illicit drugs (methamphetamine, codeine, ketamine, and nor-ketamine) in some samples. Small-volume direct injection showed great potential as an efficient method for the high-throughput determination of illicit drugs in wastewater.

A sensitive and rapid method for the simultaneous determination of twenty herbicides (aclonifen, lactofen, terbutryn, butylate, carbetamide, fluazifop-P-butyl, propanil, prometryn, isoproturon, terbumeton, pretilachlor, pendimethalin, cycloxydim, tri-allate, metolachlor, diuron, alloxydim, prosulfuron, triflusulfuron-methyl, and acetochlor) in human blood is reported herein. Liquid-liquid extraction coupled with ultra-pressure liquid chromatography-tandem mass spectrometry was employed for the simultaneous analysis of all compounds in 15 min. Validation parameters were studied through the estimation of the limits of detection and quantification, calibration curves, sensitivity, spiked recovery and precision. The limits of detection ranged from 0.1 to 1.0 ng/mL. The limits of quantification ranged from 0.5 to 2.0 ng/mL. Good linearity was obtained for all compounds with R2> 0.99 in all cases. Furthermore, interday precision (

A label-free, ultra-sensitive and turn-on method for detecting RNase A has been developed using enhanced DNA-templated silver nanoclusters (DNA-AgNCs) as the fluorescence probe. In this system, an RNA strand, which can perfectly hybridize with DNA template of nanocluster synthesis, was applied to lock the fluorescent signal of DNA-AgNCs by forming an RNA/DNA duplex. Meanwhile, the hybridized RNA/DNA duplex was used as the substrate of RNase A. The fluorescence signal of AgNCs was restored due to the degradation of RNA by RNase A. From the fluorescence signal change of this system caused by RNase A, it was found that the fluorescence signal showed a positive linear relation with RNase A concentration in the range from 0.2 pg/μL to 10 pg/μL with a detection limit of 0.098 pg/μL. Except for potential inhibitor screening and the kinetic study of this enzyme, this strategy was further used for monitoring dynamic change of RNase A in living cells successfully. In summary, the simple and sensitive method for RNase A assay can be hopefully used for drug screening in vitro and in vivo.

MicroRNAs (miRNAs) are regarded as important biomarkers for disease diagnostics and therapeutics due to their significant regulatory roles in physiologic and pathologic processes. Herein, a versatile nanoprobe based on reduced graphene oxide (rGO) and nucleic acid (DNA) probe was prepared for simultaneously visualize miR-451a and miR-214–3p in living cells. In vitro experiments demonstrated that the nanoprobe exhibits excellent selectivity and outstanding sensitivity as low as 1 nM towards miR-451a and miR-214–3p. Moreover, the detection signals of miRNAs have good linearity in their respective concentration ranges (miR-451a: 1–100 nM, Y1 = 9.3062X1+114.85 (R2 = 0.9965). miR-214–3p: 1–200 nM, Y2 = 1.4424X2+91.312 (R2 = 0.9961)). Finally, simultaneous dual-color imaging of miR-451a and miR-214–3p in human breast cancer cells (MDA-MB-231) was realized by exploiting the P1&P2@rGO nanoprobe. In summary, this simple and effective strategy provides a general sensing platform for highly sensitive detection and simultaneous imaging of dual miRNAs in living cells.

Polynucleotide kinase (PNK) is critical for nucleic acid metabolism, as its overexpression can increase ROS production and activate the inflammation pathway, leading to chronic inflammation. In this study, we proposed a new fluorescence method for monitoring PNK in vitro, natural compounds screening and intracellular imaging. Quantitative detection depicted that the limit of detection (LOD) of PNK is 0.0021 U/mL in the linear range of 0.01∼10 U/mL. Methodological evaluation showed that both of the selectivity and the inhibitory effect of ADP and EDTA on PNK activity with satisfactory results. Fluorescence imaging of inflammatory cells demonstrated the reliability of platform for capturing PNK change in situ regulated by inhibitor of natural compound NS17 isolated from Kadsura heterolita. Mechanism study showed that the inhibitor NS17 can reduce inflammation by scavenging intracellular ROS, killing inflammatory cells and down-regulating COX-2 expression, the processes of which are related with PNK activity. In summary, above results suggest that this new platform could monitor PNK activity in situ and screen inflammation inhibitors targeted on PNK.

Phosphorylation of DNA caused by T4 PNK is an important regulatory process that associated with many cellular events and diseases. Here, we proposed a DNAzyme-rGO coupled fluoresence method for T4 PNK detection. Under the optimal conditions, the approach exhibits high sensitivity with a detection limit of 0.001 U/mL, and there was a reliable linear relationship between fluorescence intensity and T4 PNK concentration in the range of T4 PNK from 0.001 U/mL ∼ 5 U/mL. Then, this method was used for kinetic analysis and effectors screening from natural compounds. Finally, the method was applied to monitor activity of T4 PNK in vitro and intracellular imaging of T4 PNK. In summary, this sensitive and specific sensing platform for T4 PNK assay can be hopefully used for clinical diagnosis, prognosis evaluation and targeted drug screening.

Hair samples from 190 relatively healthy 20- to 98-year-old volunteers from a mountain village of Tonglu city (Zhejiang province, China) were analyzed to determine the contents of 33 chemical elements (Ag, Al, As, Au, B, Ba, Be, Ca, Cd, Co, Cr, Cs, Cu, Fe, Ga, Hg, Li, Mg, Mn, Mo, Ni, Pb, Rb, Sb, Se, Sr, Th, Ti, Tl, U, V, Zn, and Zr) with the aim of assessing preliminary reference values. Mean values, median values, ranges and selected percentiles of all element concentrations in scalp hair are presented. By comparing data from different countries, it was determined that the mean concentrations of the majority of elements in our study clearly differed from the mean levels reported in the literature. The effects of gender and age on element concentrations were also investigated. Significant differences that were correlated with age and gender were determined for certain elements. For example, Fe exhibited a mean value of 11.26mg/kg for males and 4.37mg/kg for females. An age-dependent pattern for Fe was also apparent when the two age subgroups of 20-59 and 60-98 years were compared.

The concentrations of 16 elements (As, Au, Ca, Cd, Co, Cr, Cu, Fe, Hg, Mg, Mn, Mo, Ni, Se, Sr and Zn) in the hair of 40 methamphetamine (METH) abusers and control subjects were determined by inductively coupled plasma mass spectrometry (ICP-MS). Comparisons of the element levels in the hair of properly matched METH abuser and control groups revealed significant imbalances in the concentrations of 6 elements (As, Au, Ca, Cu, Mg and Sr) between the abuser and control groups. Ca (p0.01), Cu (p0.05), Mg (p0.01) and Sr (p0.01) levels are significantly lower in the hair samples of METH abusers compared to control subjects, whereas the As (p0.01) and Au (p0.01) concentrations are higher. The concentration of the remaining elements in the hair of METH abusers was similar to the concentration in the control subjects. The geometric means for each element in hair of METH abuser and control subjects are presented. The cause of these alterations is also discussed.