Toxicological responses, bioaccumulation, and metabolic fate of triclosan in Chlamydomonas reinhardtii.

Triclosan (TCS) is a broad-spectrum antimicrobial agent that is broadly used in personal care products. It has been shown to cause the contamination of a variety of aquatic environments. Since algae has been the primary producers of aquatic ecosystems, understanding the toxicological mechanisms and the metabolic fate of TCS is vital for assessing its risk in an aquatic environment. In our study, 0.5-4 mg L-1 TCS treatments for 72 h in a culture of Chlamydomonas reinhardtii (C. reinhardtii) showed progressive inhibition of cell growth and reduced the chlorophyll content. The EC50 value of C. reinhardtii after 72 h was 1.637 mg L-1, which showed its higher level of resistance to TCS in comparison with other algal species. The exposure to TCS led to oxidative injuries of algae in relation to the increment of malonaldehyde content, cell membrane permeability, and H2O2 levels. Furthermore, the oxidative stress from TCS stimulated a series of antioxidant enzyme activities and their gene expressions. Simultaneously, the accumulated TCS in C. reinhardtii arouses the detoxification/degradation-related enzymes and related gene transcriptions. In the medium, approximately 82% of TCS was removed by C. reinhardtii. Importantly, eight TCS metabolites were identified by ultra-performance liquid chromatography-high-resolution mass spectrometry and their relative abundances were measured in a time-course experiment. Six of these metabolites are reported here for the first time. The metabolic pathways of triclosan via C. reinhardtii including reductive dechlorination, hydroxylation, sulfhydrylation, and binding with thiol/cysteine/GSH/glycosyl were manifested to broaden our understanding of the environmental fate of TCS. Graphical Abstract.

Preparation of core-shell magnetic molecularly imprinted polymer nanoparticle for the rapid and selective enrichment of trace diuron from complicated matrices.

A novel magnetic MIPs (DUMIPs) was prepared by surface molecular imprinting method using superparamagnetic core-shell nanoparticle (Fe3O4@SiO2) as the sacrificial support matrix, herbicide diuron as template, α-methacrylic acid as the functional monomer, trimethylolpropane trimethacrylate as the crosslinker, azobisisobutyronitrile as the initiator, and acetonitrile as the porogen. Highly cross-linked porous surface and excellent magnetic property were characterized by Fourier-transform infrared spectroscopy, transmission electron microscopy, and vibrating sample magnetometer, respectively. The adsorption capacity of DUMIPs was 8.1 mg g-1, 2.6-fold over its corresponding non-imprinted polymers (DUNIPs). The adsorption in DUMIPs was considered as multilayer adsorption and posed high affinity to diuron, due to the better fitting to Freundilich isotherm. Competitive recognition study demonstrated DUMIPs had highly selective binding diuron. DUMIPs, as an influential sorbent has been used for selective extraction of diuron from environmental samples (paddy field water, paddy soil and grain seedlings) and the elution was determined by high efficiency liquid chromatography (HPLC). In this analytical method, various factors affecting the extraction efficiency such as pH, sorbent dosage, utilization efficiency and volumes of eluent were simultaneously investigated. Under the optimal conditions, the linearity of the method obtained is in the range of 0.02-10.0 mg L-1. The limit of detection is 0.012 mg L-1. In four spiked levels (0.04, 0.2, 1.0, and 4.0 mg kg-1), the recoveries of diuron in real samples are in the range of 83.56%-116.10% with relative standard deviations in the range of 1.21-6.81%. Importantly, compared to C18-SPE column, the MMIPs exhibited convenient separation by external magnetic field, strong clean-up capacity, and selective enrichment for diuron. Thus, the DUMIPs-based method is great potential for efficient sample preparation in the determination of trace amounts of diuron residues in complex matrices.

Research on focal nodular hyperplasia with MSCT and postprocessing.

AIM: To investigate and evaluate the pathological features and diagnostic value of focal nodular hyperplasia (FNH) with multi-section spiral computed tomography (MSCT) and postprocessing. METHODS: A total of 25 patients with FNH who had undergone MSCT and postprocessing were included in the investigation. All patients had been pathologically or clinically confirmed with FNH. A number of 75 cases of hepatic carcinomas, hemangiomas and adenomas were randomly selected at a same period for a comparative study. RESULTS: There was a single focus in 22 cases and multiple foci in 3 cases. On the plain scan, 17 lesions showed hypodensity, 7 isodensity and 4 hyperdensity (the case with fatty liver). With contrast, 28 lesions were enhanced evenly or in the nodules in the arterial phase; 13 lesions still showed hyperdensity, 11 lesions isodensity and 4 lesions hypodensity in the parenchymatous phase; in the delayed phase only 5 lesions showed hyperdensity but 9 lesions showed isodensity or slight hypodensity and 14 lesions showed hypodensity. Twelve lesions of 28 had central asteroid scars. Thickened feeding arteries in postprocessing were seen in 24 lesions, and were integrated into the parenchymatous lesions with a gradual and smooth course. On the contrary, there were no artery penetrated into the lesion found in any of comparative hepatic tumors. CONCLUSION: Doctors could make a correct diagnosis and differentiation of FNH on evaluation of the characteristic appearance on MSCT with postprocessing.

[Triple-phase helical CT in the differential diagnosis between small hepatocellular carcinoma and small hepatic cavernous hemangioma].

OBJECTIVE: To scrutinize the enhancement pattern at hepatic arterial phase (HAP), portal venous phase (PVP) and delayed phase (DP) by helical CT examination in order to differentiate small hepatocellular carcinoma (SHCC) from small hepatic cavernous hemangioma (SHCH). METHODS: In 38 patients (41 lesions) with SHCC and 35 patients (45 lesions) with SHCH, the images at HAP, PVP and DP were recorded as to the characteristic of enhancements with the average CT value at the HAP monitored and compared. RESULTS: The enhancement patterns of SHCC at the HAP, PVP, and DP were assessed as hyper-hypo-hypodense in 20 lesions, hyper-iso-hypodense in 6 lesions, hyper-hyper-hypodense in 3 lesions, hyper-iso-isodense in 5 lesions, iso-hypo-hypodense in 3 lesions, and hypo-hypo-hypodense in 4 lesions. The enhancement patterns of the SHCH were assessed as a peripheral hyperdense nodular at HAP, then progressively enlarged at PVP and turned into a isodense or homogeneous hyperdense nodular at DP in 27 lesions, hyper-hyper-iso or hyperdense in 9 lesions, hyper-iso-isodense in 3 lesions, hypo-hypo-hypodense in 6 lesions. The enhancement CT values at the HAP of homogeneous hyperdense SHCC and SHCH were (40.4 +/- 15.5) Hounsfield Unit (HU) and (102.8 +/- 18.9) HU respectively (P < 0.01). CONCLUSION: Most of the small hepatocellular carcinoma and small hepatic cavernous hemangioma have typical appearance by triple-phase helical CT examination, and can easily and properly be diagnosed. But it is difficult to distinguish SHCC from SHCH with atypical appearance in isolated cases. Hence differentiation may be difficult. Therefore, further examinations such as MRI, ultra-sonography or isotope scintigraphy are helpful in the differential diagnosis.