Custom G4 Microarrays Reveal Selective G-Quadruplex Recognition of Small Molecule BMVC: A Large-Scale Assessment of Ligand Binding Selectivity.

G-quadruplexes (G4) are considered new drug targets for human diseases such as cancer. More than 10,000 G4s have been discovered in human chromatin, posing challenges for assessing the selectivity of a G4-interactive ligand. 3,6-bis(1-Methyl-4-vinylpyridinium) carbazole diiodide (BMVC) is the first fluorescent small molecule for G4 detection in vivo. Our previous structural study shows that BMVC binds to the MYC promoter G4 (MycG4) with high specificity. Here, we utilize high-throughput, large-scale custom DNA G4 microarrays to analyze the G4-binding selectivity of BMVC. BMVC preferentially binds to the parallel MycG4 and selectively recognizes flanking sequences of parallel G4s, especially the 3'-flanking thymine. Importantly, the microarray results are confirmed by orthogonal NMR and fluorescence binding analyses. Our study demonstrates the potential of custom G4 microarrays as a platform to broadly and unbiasedly assess the binding selectivity of G4-interactive ligands, and to help understand the properties that govern molecular recognition.

A low-cost and high-efficiency carbazole-based porous organic polymer as a novel sorbent for solid-phase extraction of triazine herbicides in vegetables.

In this study, a porous organic polymer (denoted as Car-DMB) was fabricated by a simple one-step crosslinking polymerization of carbazole and p-dimethoxybenzene for the first time. Then the Car-DMB was served as adsorbent of solid phase extraction to enrich triazine herbicides from white gourd, tomato and soybean milk samples prior to their determination by high performance liquid chromatography. Under the optimal conditions, the response linearity was in the range of 0.3-100.0 ng g-1 for white gourds and tomato samples, and 0.5-100.0 ng mL-1 for soybean milk, with the coefficient of determination higher than 0.996. The detection limits were 0.1-0.2 ng g-1 for white gourd and tomato samples, and 0.15-0.3 ng mL-1 for soybean milk. The adsorption mechanism of the Car-DMB for the triazines was attributed to the strong H-bonding and weak π-π interactions. The efficient extraction for several other compounds demonstrated that Car-DMB holds great potential for diverse analysis applications.

Two-Photon Probe for TNF-α. Assessment of the Transmembrane TNF-α Level in Human Colon Tissue by Two-Photon Microscopy.

We developed Pyr1-infliximab: a two-photon probe for TNF-α. Pyr1-infliximab showed absorption maxima at 280 and 438 nm and an emission maximum at 610 nm in an aqueous buffer and effective two-photon action cross-section values of (520-2830) × 10-50 cm4s/photon in RAW 264.7 cells. After this probe was labeled, it was possible to detect Pyr1-infliximab-transmembrane TNF-α complexes in a live cell and to determine the relative proportion of these complexes in human colon tissues. This proportion among healthy, possibly inflamed, and inflamed tissues of patients with ulcerative colitis was found to be 1.0/4.5/10. This probe may find useful applications for selective detection of transmembrane TNF-α in a live cell or tissue, for quantification of inflammation in human colon tissue or of antidrug antibodies in patients who stop responding to anti-TNF therapy, and for monitoring of the response to this therapy.

Developing new hybrid scaffold for urease inhibition based on carbazole-chalcone conjugates: Synthesis, assessment of therapeutic potential and computational docking analysis.

Although a diverse range of chemical entities offering striking therapeutic potential against urease enzyme has been reported, the key challenges (toxicity and safety) associated with these inhibitors create a large unmet medical need to unveil new, potent and safe inhibitors of urease enzyme. In this pursuit, the present study demonstrates the successful synthesis of carbazole-chalcone hybrids (4a-n) in good yields. The evaluation of the preliminary in vitro biological results showed that selected members of the investigated library of hybrid compounds possess excellent urease inhibitory efficacy. In particular, compounds 4c and 4k were the most potent inhibitors with lowest IC50 values of 8.93 ±â€¯0.21 and 6.88 ±â€¯0.42 µM, respectively. Molecular docking analysis of the most potent inhibitor 4k suggests that the compound is fitted neatly at the active site interface and mediates interaction with both nickel atoms present in the active site. Several other obvious interactions including metal-carbonyl contact, hydrogen bonding and hydrophobic interactions were also observed, playing a crucial part in the stabilization of 4k in the active site of urease.

A Low-Cost Time-Correlated Single Photon Counting Portable DNA Analyzer.

Photon-counting analysis of nucleic acids plays a key role in many diagnostics applications for its accurate and non-invasive nature. However, conventional photon-counting instrumentations are bulky and expensive due to the use of conventional optics and a lack of optimization of electronics. In this paper, we present a portable, low-cost time-correlated single photon-counting (TCSPC) analysis system for DNA detection. Both optical and electronic subsystems are carefully designed to provide effective emission filtering and size reduction, delivering good DNA detection and fluorescence lifetime extraction performance. DNA detection has been verified by fluorescence lifetime measurements of a V-carbazole conjugated fluorophore lifetime bioassay. The time-to-digital module of the proposed TCSPC system achieves a full width at half maximum (FWHM) timing resolution from 121 to 145 ps and a differential non-linearity (DNL) between -8.5% and +9.7% of the least significant bit (LSB) within the 500 ns full-scale range (FSR). With a detection limit of 6.25 nM and a dynamic range of 6.8 ns, the proposed TCSPC system demonstrates the enabling technology for rapid, point-of-care DNA diagnostics.

Low-Cost Carbazole-Based Hole-Transport Material for Highly Efficient Perovskite Solar Cells.

A low-cost carbazole-based small-molecule material, 1,3,6,8-tetra(N,N-p-dimethoxyphenylamino)-9-ethylcarbazole, was designed and synthesized through a facile three-step synthetic route. The material was characterized and applied as a hole-transport material (HTM) for low-temperature-processed planar perovskite solar cells (PSCs). Devices based on this new HTM exhibit a high power-conversion efficiency of 17.8 % that is comparable to that of PSCs based on the costly 2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene (Spiro-OMeTAD) (18.6 %) .

Sterility and Stability of Diluted Carprofen in a Multidose Vial in the Laboratory Animal Setting.

Using compounded multidose vials (cMDV) is a common practice in the laboratory animal setting, where medications often are diluted to provide appropriate doses to rodents. However, bacterial contamination of MDV has been well established in both the human and veterinary medical literature. For this study, we created 14 cMDV by diluting carprofen into sterile water (dilution, 1:10) and stored 6 cMDV each at 5 and 24 °C. The stoppers of the cMDV were not cleaned with alcohol, and all were punctured twice daily for 28 d. The sterility of the diluted carprofen was evaluated by assessing bacterial growth on days 0, 7, 14, 21, and 28 and by testing for bacterial endotoxin on days 0 and 28. We used liquid chromatography-tandem mass spectrometry to assess the stability of 2 cMDV, with each cMDV being divided into the 2 storage-temperature subsets for days 0, 7, 14, 21, and 28. Neither bacterial contamination nor endotoxin was detected, and drug stability was stable over the 28 d. We suggest that with pragmatic techniques, such as secondary containment and consistent use of new needles, the contents of cMDV can remain sterile and stable for 28 d.

Pd-Metalated Conjugated Nanoporous Polycarbazoles for Additive-Free Cyanation of Aryl Halides: Boosting Catalytic Efficiency through Spatial Modulation.

Transition-metal-catalyzed cyanation of aryl halides is a common route to benzonitriles, which are integral to many industrial procedures. However, traditional homogeneous catalysts for such processes are expensive and suffer poor recyclability, so a heterogeneous analogue is highly desired. A novel spatial modulation approach has been developed to fabricate a heterogeneous Pd-metalated nanoporous polymer, which catalyzes the cyanation of aryl halides without need for ligands. The catalyst displays high activity in the synthesis of benzonitriles, including high product yields, excellent stability and recycling, and broad functional-group tolerance.

Continuous flow photocatalysis enhanced using an aluminum mirror: rapid and selective synthesis of 2'-deoxy and 2',3'-dideoxynucleosides.

A unique photochemical flow reactor featuring quartz tubing, an aluminum mirror and temperature control has been developed for the photo-induced electron-transfer deoxygenation reaction to produce 2'-deoxy and 2',3'-dideoxynucleosides. The continuous flow format significantly increased the efficiency and selectivity of the reaction.

The fate of 4-hydroxycarbazole metabolite: metabolism and carcinogenicity assessment of a ß-adrenergic receptor modulator containing carbazole structure.

LY377604 has a potential to form 4-hydroxycarbazole, which was reported in the literature as a mutagen. This safety concern led to our investigation of the metabolism and carcinogenicity of LY377604. In in vitro studies with LY377604, 4-hydroxycarbazole was detected in the presence of liver microsomes prepared from different species. When incubated with liver slices, only the conjugate of 4-hydroxycarbazole was detected. Subsequent in vivo radio-labelled studies were conducted to characterise the formation of 4-hydroxycarbazole from LY377604. Free 4-hydroxycarbazole was not detected in vivo, but the O-glucuronide conjugate was identified as a minor metabolite in urine samples, representing 0.2% and 0.9% of the radioactive dose in rats and monkeys. The low level of circulating 4-hydroxycarbazole glucuronide conjugate was also detected in plasma. LY377604 was negative in all genetic toxicology assays and was not associated with tumour induction in a 6-month carcinogenicity study using RasH2+/- mouse model. The exposure to free 4-hydroxycarbazole was not measurable after one dose and was about 0.1%-0.2% of the parent exposure at the end of the 6-month study. These data suggested that 4-hydroxycarbazole was formed as a minor metabolite in vivo, but it was primarily conjugated and excreted in urine as the glucuronide conjugate. The absence of tumours in the carcinogenicity study combined with the exposure data suggested that the low level of free 4-hydroxycarbazole did not represent a carcinogenic risk.

Assessment of solubilization characteristics of different surfactants for carvedilol phosphate as a function of pH.

The effect of surfactants on the solubility of a new phosphate salt of carvedilol was investigated at different biorelevent pH to evaluate their solubilization capacity. Solutions of different classes of surfactants viz., anionic-sodium dodecyl sulfate (SDS) and sodium taurocholate (STC), cationic-cetyltrimethylammonium bromide (CTAB) and non-ionic-Tween 80 (T80) were prepared in the concentration range of 5-35 mmol dm(-3) in buffer solutions of pH 1.2, 3.0, 4.5, 5.8, 6.8 and 7.2. The solubility data were used to calculate the solubilization characteristics viz. molar solubilization capacity, water micelle partition coefficient, free energy of solubilization and binding constant. Solubility enhancement in basic pH was in following order: CTAB>T80>SDS>STC. CTAB and T80 showed remarkable solubility enhancement in acidic pH as well. Among the anionic surfactants, solubility in acidic medium was retarded except at pH 1.2 in case of SDS. Cationic and non-ionic surfactants were found to be suitable for enhancing the solubility of CP which can be employed for maintaining the in vitro sink condition in the basic dissolution medium. While anionic surfactants showed solubility retardant behavior which may be exploited in increasing the drug entrapment efficiency of a colloidal drug delivery system formulated by emulsification technique.

Design and evaluation of naphthol- and carbazole-containing fluorescent sigma ligands as potential probes for receptor binding studies.

Some 3,3-dimethyl-1-(3-naphthylpropyl)piperidine and 1-cyclohexyl-4-(3-naphthylpropyl)piperazine derivatives, structurally containing naphthol as a fluorescent moiety, were prepared for being potentially used as fluorescent sigma ligands. Structurally related analogs were also prepared, where the naphthalene nucleus was replaced by the fluorescent carbazole moiety and chain length was varied. For all compounds the in vitro affinities toward sigma receptors and Delta8-Delta7 sterol isomerase site were measured, and the fluorescent properties were determined. Compound 19 gave the best results both for sigma receptor affinities (sigma1, Ki = 6.78 nM and sigma2, Ki = 26.4 nM) and fluorescence features; thus, it was chosen for in vitro saturation binding analysis at sigma receptors. The good results obtained in such assay suggested that the fluorescent compound 19 could be used instead of a radioligand in "green" binding assays.

Frovatriptan Vernalis.

Vanguard (now Vernalis) has developed frovatriptan, a selective 5-HT1B/1D partial agonist licensed from GlaxoSmithKline as a potential treatment for migraine [188478], [194382], [377863].