Sensitive Monitoring of Fluoroquinolones in Milk and Honey Using Multiple Monolithic Fiber Solid-Phase Microextraction Coupled to Liquid Chromatography Tandem Mass Spectrometry

In the present study, a new multiple monolithic fiber solid-phase microextraction (MMF-SPME) based on poly­(apronal-<i>co</i>-divinylbenzene/ethylenedimethacrylate) monolith (APDE) was synthesized. The effect of the preparation parameters of APED on extraction efficiency was studied thoroughly. The combination of APDE/MMF-SPME with high-performance liquid chromatography tandem mass spectrometry detection (HPLC/MS-MS) was developed for sensitive monitoring of ultratrace fluoroquinolones (FQs) in foodstuffs, including milk and honey samples. Under the optimized experimental conditions, the limits of detection (S/N = 3) for the targeted FQs ranged from 0.0019 to 0.018 μg/kg in milk and 0.0010 to 0.0028 μg/kg in honey. The relative standard deviations (RSDs) for method reproducibility were less than 9% in all samples. The established method was successfully applied for the monitoring of FQs residues in milk and honey samples with the recoveries between 74.5% and 116% (RSDs were in the range 0.9–9.5%). In comparison to previous methods, the developed APDE/MMF-SPME-HPLC/MS-MS showed some merits, including satisfactory sensitivity, simplicity, high cost-effectiveness, and low consumption of organic solvent

Accelerated resolution of lung inflammation in <i>FoxM1 Tg</i> mice.

<p>(<b>A</b>) MPO activities in lung tissues. Lung tissues at indicated times post-CLP challenge were collected for MPO activity determination. Lung tissues from sham-operated mice at 24 h post-surgery were collected as controls. Data are expressed as mean ± SD (n = 3–5). *, <i>P</i><0.001 versus WT; **, <i>P</i><0.05 versus WT. (<b>B</b>) Representative micrographs of H & E staining of lung sections. At 24 h post-surgery, lungs were fixed for sectioning and H & E staining. Arrows indicate perivascular leukocyte infiltration. Scale bar, 50 µm.</p

Rapid recovery of vascular permeability in <i>FoxM1 Tg</i> lungs following CLP challenge.

<p>(<b>A</b>) Representative Western blotting demonstrating increased expression of FoxM1 in <i>FoxM1 Tg</i> lungs. Thirty µg of lung lysates were loaded per lane. FoxM1 expression was detected with anti-FoxM1 antibody. The same membrane was immunoblotted with an anti-β-actin antibody for loading control. (<b>B</b>) Lung vascular permeability assessed by EBA extravasation assay. Various times following CLP challenge, mouse lung tissues were collected for EBA assay. Lung tissues from sham-operated mice at 24 h post-surgery were collected as controls. Data are expressed as mean ± SD (n = 3–5 per group). *, <i>P</i><0.01 versus <i>FoxM1 Tg</i>. (<b>C</b>) Lung wet/dry weight ratio. At 24 h post-surgery, lung tissues were collected and dried at 60°C for 3 days. Data are expressed as mean ± SD (n = 4). *, <i>P</i><0.05 versus WT.</p

FoxM1-induced endothelial cell proliferation in <i>FoxM1 Tg</i> lungs following CLP challenge.

<p>(<b>A</b>) Representative micrographs of immunofluorescent staining. Lung tissues were collected at 24 h post-CLP challenge, sectioned and immunostained with anti-BrdU (green) and anti-vWF and CD31 (red) antibodies. Nuclei were counterstained with DAPI (blue). Arrows indicate proliferating EC. Scale bar, 50 µm. (<b>B</b>) Quantification of BrdU-positive nuclei. Data are expressed as mean ± SD (n = 4 per group). *, <i>P</i><0.001 versus WT. (<b>C</b>) Quantification of BrdU-positive EC (vWF⁺ or CD31⁺) and non-EC (vWF^- or CD31⁻). BrdU-positive EC were quantified in small vessels (diameter ≤ 100 µm) and capillaries. Data are expressed as mean ± SD (n = 4). <i>P</i><0.001 versus WT.</p

Impaired endothelial repair in <i>FoxM1 CKO</i> lungs following CLP challenge.

<p>(<b>A</b>) EBA extravasation assay demonstrating sustained vascular leakiness in <i>FoxM1 CKO</i> lungs. Data are expressed as mean ± SD (n = 4–5). *, <i>P</i><0.01 versus WT-18 h; **, <i>P</i><0.005 versus WT-18 h; #, <i>P</i>>0.5 versus <i>FoxM1 CKO</i>-18 h. (<b>B</b>) Persistent increase of MPO activity in <i>FoxM1 CKO</i> lungs following CLP challenge. Data are expressed as mean ± SD (n = 4–5). *, <i>P</i><0.01 versus WT-18 h; **, <i>P</i><0.005 versus WT-18 h; #, <i>P</i>>0.5 versus <i>FoxM1 CKO</i>-18 h.</p

Time course of FoxM1 expression in lungs following CLP challenge.

<p>Lung tissues were collected at indicated times post-CLP challenge or 24 h post-sham surgery for RNA isolation and QRT-PCR analysis. Expression of endogenous mouse FoxM1 was assessed with the primers specific with mouse FoxM1 (<b>A</b>) whereas expression of the transgene was analyzed with the primers specific with human FoxM1 (<b>B</b>). Data are expressed as mean ± SD (n = 3–5 per times). *, <i>P</i><0.01 versus Sham; **, P<0.001. Mouse FoxM1 was similarly induced in WT or <i>FoxM1 Tg</i> lungs following CLP challenge but not in <i>FoxM1 CKO</i> lungs. Human FoxM1 was constitutively expressed in <i>FoxM1 Tg</i> lungs at various times post-CLP.</p

Increased survival of <i>FoxM1 Tg</i> mice following CLP challenge.

<p>3 month old mice were monitored for 7 days to determine the survival rate following CLP challenge (n = 13 WT and 14 <i>FoxM1 Tg</i>). Sham-operated mice (n = 5 WT or <i>FoxM1 Tg</i>) were also monitored for survival. *, <i>P</i><0.001 versus CLP-WT. Tg, <i>FoxM1 Tg</i>.</p

Normalized expression of proinflammatory cytokines and adhesion molecule in <i>FoxM1 Tg</i> lungs at 24 h post-CLP.

<p>RNA were isolated from lungs collected at 24 h post-surgery and QRT-PCR analysis were employed to assess the expression levels. Data are expressed as mean ± SD (n = 3–4). *, <i>P</i><0.05 versus WT-sham.</p

Early induction of expression of FoxM1 target genes essential for cell cycle progression in <i>FoxM1 Tg</i> lungs.

<p>(<b>A</b>–<b>D</b>) QRT-PCR analysis of expression of FoxM1 target genes. Lung tissues were collected at indicated times post-CLP challenge or 24 h post-sham operation for RNA isolation and QRT-PCR analysis. Data are expressed as mean ± SD (n = 3–5 per group). *, <i>P</i><0.001 versus WT; **, <i>P</i><0.05 versus WT. (<b>E</b>) Representative Western blotting demonstrating FoxM1-mediated induction of Cdc25C protein expression. Lung tissues were collected at various times post surgery and lysed for examination of Cdc25C protein levels by Western blotting. The same membrane was blotted with anti-β-actin as a loading control. The experiment was repeated three times with similar data.</p

Highly Permeable Monolith-based Multichannel In-Tip Microextraction Apparatus for Simultaneous Field Sample Preparation of Pesticides and Heavy Metal Ions in Environmental Waters

A portable multichannel in-tip microextraction-based field sample preparation (FSP) apparatus was developed using polymer-based monoliths as an extraction phase. The construction of the FSP device is quite facile and convenient. More specifically, according to the chemical properties of studied analytes, functional-rich and high-permeability monoliths were in situ synthesized in pipet tips. After that, three tips containing the sorbents were mounted to three syringes, which were connected to a screw motor employed to drive the syringes and accurately regulate the flow rates in the adsorption and desorption stages. Because of the multifunction groups in the monoliths, the sorbents displayed satisfactory coextraction performance for pesticides (carbamates and triazoles) and heavy metal ions (Cd2+, Pb2+, and Cu2+) under the optimized conditions. The practicability of the proposed apparatus was demonstrated by the quick and simultaneous FSP of studied analytes in various environmental waters and combined with high-performance liquid chromatography/diode-array detection (for pesticides) and atomic absorption spectrometry (for metal ion) analysis. The results indicated that the limits of detection for the pesticides and metal ions were in the range of 0.36 to 1.2 ng/L and 0.061 to 0.40 ng/L, respectively, with ideal coefficients of determination. Furthermore, the results obtained with the constructed device were quite comparable to those obtained with the traditional laboratory extraction process, which demonstrated that the newly developed apparatus possesses the expected application in the high-throughput FSP of pesticides and heavy metal ions in water samples