A new FRET probe for ratiometric fluorescence detecting mitochondria-localized drug activation and imaging endogenous hydroxyl radicals in zebrafish.

A new FRET probe has been prepared for ratiometric fluorescence detection of hydroxyl radicals. It has been successfully used for detecting mitochondria-localized drug activation in living cells and imaging endogenous hydroxyl radicals in zebrafish gastrointestinal (GI) tracts under normal culturing conditions.

A new fluorescent probe for sensing of biothiols and screening of acetylcholinesterase inhibitors.

A new N2O-type BODIPY probe (LF-Bop) has been proposed for the selective and sensitive detection of biologically relevant small molecular thiols. This detection is based on the Michael addition reaction between the thiol and nitrostyrene groups in the probe, which decreases the quenching effect from the nitro group, thus resulting in the recovery of the deep-red fluorescence from the BODIPY structure. The results show that LF-Bop is able to detect all tested free thiols through a fluorescence turn-on assay. The lowest limit of detection (LOD) for glutathione was found to be down to nanomolar levels (220 nM). Based on this probe, we have developed a new fluorescence assay for the screening of acetylcholinesterase inhibitors. In total, 11 natural and synthetic alkaloids have been evaluated. Both experimental measurements and theoretical molecular docking results reveal that both natural berberine and its synthetic derivative dihydroberberine are potential inhibitors of acetylcholinesterase.

A ratiometric fluorescent probe for sensitive determination of the important glycopeptide antibiotic vancomycin.

A novel sensitive and selective probe for the important antibiotic vancomycin (Van) has been synthesized by integrating a coumarin and a fluorescein as dual fluorescence reporters and a Van binding peptide D-Ala-D-Ala. Only weak green fluorescence was initially observed, which was mostly attributed to fluorescence self-quenching induced by fluorophore stacking. Upon the binding of Van with the D-Ala-D-Ala peptide, the fluorescence turned on, probably due the disaggregation of fluorophores. The intensity ratio of the dual emission bands I519/I446 exhibited an excellent linear relationship with the concentration of Van increasing from 0-20 µM in synthetic urine. The lowest detection limit was calculated to be 92.8 nM in urine, which made the probe applicable in clinically relevant concentration ranges. The synthetic probe has also shown the potential for Van detection in human serum. More interestingly, this probe has been successfully applied for in vivo imaging of Van in zebrafish. Graphical Abstract.

An unexpected Griess reaction on the important anti-malarial drug primaquine and its application for drug determination.

Primaquine (PMQ), a well-known anti-malarial drug, is of increasing importance as people moving toward global malaria eradication. PMQ has serious side effects that it often causes acute hemolytic toxicity in people with glucose-6-phosphate dehydrogenase (G6PD) deficiency. The development of simple and reliable approaches for quantitative dose monitoring is thus becoming important during malarial treatment with PMQ. Herein, an unexpected Griess reaction on PMQ was systematically studied. The reaction happened between substituted aniline and a primaquine molecule in the presence of nitrite. Both experimental measurements and theoretic calculation showed that UV-vis absorption of the azo products varied because of different electron contributing effects of substituents. Based on the optimized conditions, a novel colorimetric method has been developed for PMQ determination with excellent sensitivity and selectivity. The detection limits for PMQ in water and synthetic urine samples were down to nanomolar range. More importantly, this method has been successfully used to quantify PMQ from human serum samples within clinically relevant concentration ranges.

A novel strategy for colorimetric detection of hydroxyl radicals based on a modified Griess test.

Hydroxyl radical (•OH) is the most reactive oxygen species involved in many environmental and biological processes. The development of simple and reliable methods to quantitatively determine hydroxyl radicals is desired. Herein, a colorimetric strategy based on a modified Griess test has been presented. The detection started with the nitrite release from nitroimidazoles (nIm) upon its specific reaction with •OH radicals and subsequently nitrite quantification by Griess reagent. The result showed that this nitroimidazole modified Griess test (nIm-Griess) was successfully adapted for the measurement of •OH radicals generated by Fenton reaction, water radiolysis, as well as the activation of two antimalarials artemisinin (Art) and dihydroartemisinin (DHA).

Computed tomography and magnetic resonance imaging observations of rhabdomyosarcoma in the head and neck.

Head and neck (HN) rhabdomyosarcoma (RMS) is an aggressive malignancy, which is rarely encountered and is commonly misdiagnosed as another type of tumor. The aim of the present study was to investigate the computed tomography (CT) and magnetic resonance imaging (MRI) features of HNRMS and analyze the correlations between the imaging observations and the pathological subtypes. A total of 10 HNRMS patients (three males and seven females; median age, 16 years) were reviewed retrospectively by only CT (n=1), only MRI (n=2), as well as CT and MRI (n=7). In addition, the clinical data, imaging observations and pathological results were recorded and analyzed. The origins of the 10 HNRMSs (eight embryonal and two alveolar subtypes) included the ethmoid sinus (n=4), maxillary sinus (n=1), orbit (n=3), nasopharynx (n=1) and frontotemporal subcutaneous area (n=1). On the CT and MRI images, the soft-tissue masses exhibited ill-defined borders (n=9), bony destruction (n=10), multi-cavity growth (n=7) and cervical lymph node metastasis (n=2), whereas calcification and hemorrhaging were not identified. On CT, eight of the HNRMSs appeared slightly hypodense (2/8) or isodense (6/8) with homogeneous enhancement (4/4). On T1-weighted images (WI), nine tumors exhibited isointensity (9/9) and on T2WI, six tumors demonstrated homogeneous hyperintensity with homogeneous enhancement on contrast-enhanced (CE)-T1WI. In addition, three embryonal RMSs, which originated from the ethmoid sinus, exhibited heterogeneous hyperintensity on T2WI and nodule-shaped enhancement patterns on CE-T1WI. The results of the present study indicated that MRI may accurately demonstrate the location and extent of HNRMS and that the imaging features of HNRMS may be similar to those of other tumors. However, a tumor exhibiting heterogeneous hyperintensity on T2WI and a nodule-shaped enhancement pattern on CE-T1WI in the ethmoid sinus may present specific MRI features, which clearly indicates the botryoid subtype of embryonal RMS.