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ABSTRACT 8-Amino-5-chloro-7-phenylpyrido[3,4-d]pyridazine-1,4(2H,3H)dione (L-012) was recently synthesized as a new chemiluminescence (CL) probe; the light intensity and the sensitivity of L-012 are higher than those of other CL probes such as luminol. Previously, our group developed four lophine-based CL enhancers of the horseradish peroxidase (HRP)-catalyzed CL oxidation of luminol, namely 2-(4-hydroxyphenyl)-4,5-diphenylimidazole (HDI), 2-(4-hydroxyphenyl)-4,5-di(2-pyridyl)imidazole (HPI), 4-(4,5-diphenyl-1H-imidazol-2-yl)phenylboronic acid (DPA), and 4-[4,5-di(2-pyridyl)-1H-imidazol-2-yl]phenylboronic acid (DPPA), and showed that DPPA was suitable for the photographic detection of HRP. In this study, we replaced luminol with L-012 and evaluated these as L-012-dependent CL enhancers. In addition, to detect HRP and/or H2O2 with higher sensitivity, each detection condition for the L-012-HRP-H2O2 enhanced CL was optimized. All the derivatives enhanced the L-012-dependent CL as well as luminol CL; HPI generated the highest enhanced luminescence. Under optimized conditions for HRP detection, the detection limit of HRP was 0.08 fmol. By contrast, the detection limit of HRP with the enhanced L-012-dependent CL using 4-iodophenol, which is a common enhancer of luminol CL, was 1.1 fmol. With regard to H2O2 detection, the detection limits for enhanced CL with HPI and 4-iodophenol were 0.29 and 1.5 pmol, respectively. Therefore, it is demonstrated that HPI is the most superior L-012-dependent CL enhancer. Copyright © 2013 John Wiley & Sons, Ltd. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Abstract: The epitaxial growth of β-FeSi2 films produced on flat and patterned Si(001) substrates under various substrate temperatures (T s) with deposition rates of Fe (V Fe) was investigated by transmission electron microscopy (TEM). In the film deposited on the flat Si(001) substrate, precipitates of flat-bottom shaped β-FeSi2 and those of round-bottom shaped α-FeSi2 were formed at T s =500 °C and V Fe =0.02 nm/s. The β-FeSi2 adopted the epitaxy to (001)Si plane, while α-FeSi2 selected the epitaxy to {111}Si planes inside the Si matrix. At T s =350 °C and V Fe =0.01 nm/s, a continuous β-FeSi2 layer were formed epitaxially on the Si(001) substrate without forming α-FeSi2. It was found that the lower temperature and the higher Fe-concentration suppress the formation of α-FeSi2 and promote the formation of β-FeSi2. In addition, the morphology of β-FeSi2 changed from fine isolated precipitates (islands) to a continuous layer with increasing the deposition rate and the substrate temperature. In the film deposited on the patterned Si(001) substrate at T s =500 °C and V Fe =0.02 nm/s, on the other hand, both β- and α-FeSi2 precipitates were formed on the top-hills and the valleys of the patterned substrate, while only α-FeSi2 precipitates were formed on the sidewalls. These results demonstrate that not only the growth conditions but also geometric situations affect strongly the epitaxial growth of FeSi2 precipitates. [Copyright &y& Elsevier]

The quenching effects of non-water-soluble (NWS) and water-soluble (WS) rosemary extracts against active oxygen species were investigated by a chemiluminescent assay. The EC50 values of the NWS extract for superoxide anion, singlet oxygen, hydroxy radical, hypochlorite ion and linolenic acid peroxide were 0.23 ± 0.02, 0.89 ± 0.06, 0.067 ± 0.005, 0.098 ± 0.009 and 0.020 ± 0.004 mg/ml (n=3), respectively. The quenching effects of the NWS extract on superoxide anion, singlet oxygen, hydroxy radical and hypochlorite ion were significantly higher than those of the commercially-available hexane extracts of rosemary at 1.0 mg/ml (p<0.05). The WS extract also showed higher quenching effects (except for singlet oxygen) and its EC50 values were 0.30 ± 0.02 for superoxide, 0.0048 ± 0.0005 for hydroxy radical, 0.58 ± 0.05 for hypochlorite ion and 0.13 ± 0.03 mg/ml for linolenic acid peroxide. The two extracts prepared might be available as antioxidants for foodstuffs. [Copyright &y& Elsevier]

Gamma-aminobutyric acid (GABA), which has attracted much attention as a bioactive ingredient, is used in functional foods. Recently, electronic cigarette (e-cigarette) products for inhaling vaporized GABA have become commercially available. In this study, we developed a high-performance liquid chromatography-fluorescence method for detecting GABA derivatized with 4-(N,N-dimethylaminosulfonyl)-7-fluoro-2,1,3-benzoxadiazole (DBD-F) in cigarette smoke extract (CSE). The vaporized GABA captured in CSE was derivatized with DBD-F under moderate conditions (80°C, 30 min). After chromatographic separation, the DBD-GABA derivative was detected at 437 and 558 nm. The calibration curve of GABA ranging from 10 to 20,000 ng/mL showed good linearity (more than 0.999). The limit of detection at a signal-to-noise ratio of 3 was 1.1 ng/mL. The method was applied to the detection of GABA in e-liquid and CSE for two kinds of e-cigarette products, and the estimated collection efficiency of GABA was approximately 25%. Furthermore, the detection of minor components, such as glutamine, glutamic acid, and arginine, in the e-liquid proved that the GABA used in the e-cigarette was prepared by microbial fermentation., (© 2024 The Author(s). Luminescence published by John Wiley & Sons Ltd.)

This work introduces an extremely easy method for preparing luminescent carbon dots (CDs) at ambient temperature using 1,2-naphthoquinone sulphonate and ethylenediamine as precursors via self-exothermic reaction without energy input. The as-obtained CDs have a high quantum yield (34.1 %), a production yield of 21.2 %, and a small size diameter (3.44 nm). Various techniques (NMR, TEM, EDX-mapping, XPS, XRD, FT-IR, fluorescence, and UV-visible spectroscopy) were used to characterize the prepared CDs. The CDs exhibited an excitation-independent emission with λ ex of 275 nm, demonstrating their homogeneity and high purity. The anticancer drug vincristine (VCR) quantitively quenched the fluorescent signal of the synthesized CDs, allowing their application as the first fluorescent nano-sensor to determine VCR. The quenching effect was linear within the range of 0.2-5.0 μg mL -1 , enabling the determination of VCR in vials, plasma, and for content uniformity testing with a detection limit of 0.06 μg mL -1 . Moreover, the synthesized CDs were employed as a bio-sensing platform to detect VCR in cancer cells owing to their good selectivity, excellent biocompatibility, minimal cytotoxicity, and high stability. The fabrication of CDs with excellent properties at room temperature under mild conditions paves the way for new advancements in the room temperature synthesis of CDs and offers a highly efficient alternative to traditional synthesis approaches., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Background: L-p-Boronophehylalanine (BPA) is used in boron neutron capture therapy (BNCT), which is a novel selective cancer radiotherapy technique. It is important to measure BPA levels in human blood for effective radiotherapy; a prompt gamma-ray spectrometer, ICP-AES, and ICP-MS have been used for this purpose. However, these methods require sophisticated and expensive apparatuses as well as experienced analysts. Herein, we propose an HPLC-FL method for the determination of BPA after precolumn derivatization. A new fluorogenic reagent for aryl boronic acid derivatives, namely, 4-iodobenzonitrile, was employed for the fluorogenic derivatization of BPA based on the Suzuki coupling reaction., Results: After the fluorogenic derivatization, a fluorescent cyanobiphenyl derivative is formed with maximum fluorescence at 335 nm after excitation at 290 nm. The developed method showed good linearity (r 2 =0.997) over the concentration range of 0.5-1000 nmol/L, and the detection limit (S/N = 3) was 0.26 nmol/L. The proposed method is more sensitive than previously reported methods for the determination of BPA, including the ICP-MS. Finally, the proposed method was successively applied to the measurement of BPA in human whole blood samples with a good recovery rate (≥95.7 %) using only 10 μL of blood sample. The proposed method offers a simple and efficient solution for monitoring BPA levels in BNCT-treated patients., Significance: 4-Iodobenzonitrile was investigated as a new fluorogenic reagent for BPA based on Suzuki coupling. A new HPLC-FL method for BPA in whole blood samples with ultrasensitivity was developed. The developed method is superior in sensitivity to all previously reported methods for BPA. The method requires only a very small sample volume, making it suitable for micro-blood analysis of BPA via fingerstick sampling., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Palladium-catalyzed coupling reactions are versatile and powerful tools for the construction of carbon-carbon bonds in organic synthesis. Although these reactions have favorable features that proceed selectively in mild reaction conditions using aqueous organic solvents, no attention has been given to their application in the field of biomedical analysis. Therefore, we focused on these reactions and evaluated the scope and limitations of their analytical performance. In this review, we describe the pros and cons and future trends of fluorescence derivatization of pharmaceuticals and biomolecules based on palladium-catalyzed coupling reactions such as Suzuki-Miyaura coupling, Mizoroki-Heck coupling, and Sonogashira coupling reactions for HPLC analysis., (© 2024 John Wiley & Sons Ltd.)

Currently, e-cigarette products to inhale caffeine (Caf) are commercially available and widely used. Guarana extract (GE) is used as the caffeine source in some e-cigarette products. In this study, an LC-MS/MS analysis of components in the smoke from e-cigarettes with GE was performed. The concentration ranges of Caf and the minor components theophylline (TP), theobromine (TB), and paraxanthine (PX) in e-liquid and cigarette smoke extract (CSE) of five e-cigarette products were determined. The concentration ranges of e-liquid and CSE were 2.17-8.62 mg/mL and 0.17-1.17 µg/puff for Caf, 0.09-37.58 µg/mL and 0.03-11.88 ng/puff for TB, 50.28-185.26 ng/mL and 0.00-0.05 ng/puff for TP, and 0.44-4.09 µg/mL and 0.03-0.20 ng/puff for PX, respectively. By comparing the peak area ratios of e-liquid and CSE, we clarified that the heat degradation of Caf to its related components in GE products was accelerated. Epicatechin, which is another typical component in GE, was determined for CSE, but not for e-liquid., (© 2024. The Author(s), under exclusive licence to The Japan Society for Analytical Chemistry.)

Biotin, or vitamin B7, is essential for metabolic reactions. It must be obtained from external sources such as food and biotin/vitamin supplements because it is not biosynthesized by mammals. Therefore, there is a need to monitor its levels in supplements. However, biotin detection methods, which include chromatographic, immune, enzymatic, and microbial assays, are tedious, time-consuming, and expensive. Thus, we synthesized a product called biotin-naphthoquinone, which produces chemiluminescence upon its redox cycle reaction with dithiothreitol and luminol; then it was used as a chemiluminescence sensor for biotin-avidin interaction. When a quinone biotinylated compound binds avidin, the chemiluminescence decreases noticeably due to the proximity between quinone and avidin, and when free biotin is added in a competitive assay, the chemiluminescence returns. The chemiluminescence is regained as the free biotin displaces biotinylated quinone in its complex with avidin, freeing biotin-naphthoquinone. Many experiments, including the use of a biotin-free quinone, proved the competitive nature of the assay. The competitive assay method used in this study was linear in the range of 1.0-100 µM with a detection limit of 0.58 µM. The competitive chemiluminescence assay could detect biotin in vitamin B7 tablets with good recovery of 91.3 to 110% and respectable precision (RSD < 8.7%).

Carbon monoxide (CO) is a toxic, hazardous gas that has a colorless and odorless nature. On the other hand, CO possesses some physiological roles as a signaling molecule that regulates neurotransmitters in addition to its hazardous effects. Because of the dual nature of CO, there is a need to develop a sensitive, selective, and rapid method for its detection. Herein, we designed and synthesized a turn-on fluorescence probe, 2-(2'-nitrophenyl)-4(3 H )-quinazolinone (NPQ), for the detection of CO. NPQ provided a turn-on fluorescence response to CO and the fluorescence intensity at 500 nm was increased with increasing the concentration of CO. This fluorescence enhancement could be attributed to the conversion of the nitro group of NPQ to an amino group by the reducing ability of CO. The fluorescence assay for CO using NPQ as a reagent was confirmed to have a good linear relationship in the range of 1.0 to 50 µM with an excellent correlation coefficient (r) of 0.997 and good sensitivity down to a limit of detection at 0.73 µM (20 ppb) defined as mean blank+3SD. Finally, we successfully applied NPQ to the preparation of a test paper that can detect CO generated from charcoal combustion.

The most used kind of immunoassay is enzyme-linked immunosorbent assay (ELISA); however, enzymes suffer from steric effects, low stability, and high cost. Our research group has been developing quinone-linked immunosorbent assay (QuLISA) as a new promising approach for stable and cost-efficient immunoassay. However, the developed QuLISA suffered from low water-solubility of synthesized quinone labels and their moderate sensitivity. Herein, we developed a new approach for signal multiplication of QuLISA utilizing the water-soluble quinone anthracycline, doxorubicin, coupled with dextran for signal multiplication. A new compound, Biotin-DexDox, was prepared in which doxorubicin was assembled on oxidized dextran 40, and then it was biotinylated. The redox-cycle-based chemiluminescence and the colorimetric reaction of Biotin-DexDox were optimized and evaluated, and they showed very good sensitivity down to 0.25 and 0.23 nM, respectively. Then, Biotin-DexDox was employed for the detection of biotinylated antibodies utilizing avidin as a binder and a colorimetric assay of the formed complex through its contained doxorubicin redox reaction with NaBH 4 and imidazolium salt yielding strong absorbance at 510 nm. The method could detect the plate-fixed antibody down to 0.55 nM. Hence, the application of Biotin-DexDox in QuLISA was successfully demonstrated and showed a significant improvement in its sensitivity and applicability to aqueous assays.

Quinones are frequently used as derivatization reagents in HPLC analysis to improve detection sensitivity. In the present study, a simple, sensitive, and selective chemiluminescence (CL) derivatization strategy for biogenic amines, prior to their HPLC-CL analysis, was developed. The novel CL derivatization strategy was established based on using anthraquinone-2-carbonyl chloride as derivatizing agent for amines and then using the unique property of the quinones' moiety to generate reactive oxygen species (ROS) in response to UV irradiation. Typical amines such as tryptamine and phenethylamine were derivatized with anthraquinone-2-carbonyl chloride and then injected into an HPLC system equipped with an online photoreactor. The anthraquinone-tagged amines are separated and then UV-irradiated when they pass through a photoreactor to generate ROS from the quinone moiety of the derivative. Tryptamine and phenethylamine can be determined by measuring the chemiluminescence intensity produced by the reaction of the generated ROS with luminol. The chemiluminescence disappears when the photoreactor is turned off, suggesting that ROS are no longer generated from the quinone moiety in the absence of UV irradiation. This result indicates that the generation of ROS could be controlled by turning the photoreactor on and off. Under the optimized conditions, the limits of detection for tryptamine and phenethylamine were 124 and 84 nM, respectively. The developed method is successfully applied to determine the concentrations of tryptamine and phenethylamine in wine samples.

A sensitive and stable signal multiplied quinone-linked immunosorbent assay (Multi-QuLISA) was developed. In Multi-QuLISA, an oligomerized quinone linked to biotin, namely biotin-8mer-naphthoquinone (Bio8mer-NQ), is used as a signal-generating label. Bio8mer-NQ is formed from a dendrigraft poly-l-lysine generation 1 (DPLL G1), a controlled branched oligomer composed of eight lysine moieties with nine free amino groups as a backbone. One of the nine amino groups of DPLL G1 is attached to biotin moiety, while the other eight are attached to 1,2-naphthoquinone-4-sulfonate (NQS). Bio8mer-NQ labels a biotinylated detection antibody using avidin as a co-binder. Then, multi-quinones in Bio8mer-NQ undergo a redox cycle with dithiothreitol and luminol, generating strong chemiluminescence. Standard ELISA uses a label enzyme that suffers from vulnerability in different conditions and poor stability. Bio8mer-NQ showed better stability than the enzyme (biotin-HRP) under different drastic pH and temperature conditions, hydrolytic enzymes, etc. Furthermore, Bio8mer-NQ was used as both chemiluminescence and colorimetric label based on the redox cycle of quinone, and it had LODs of 1.5 and 6.5 nM, respectively. The method could detect biotinylated immunocomplex in an in-house designed immunoassay down to 0.2 nM, which is about 25 times more sensitive than biotin HRP. Eventually, Bio8mer-NQ was applied successfully in Multi-QuLISA for detecting β-casein with a sensitivity of 3.2 ng/mL, while the conventional ELISA had an LOD of 35 ng/mL. Overall, Bio8mer-NQ is a stable compound that could be used as an excellent replacement for the enzyme in immunoassay and can be used in both colorimetric and chemiluminescence assays with good sensitivity., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Purpose: Electronic cigarettes (e-cigarettes) are used widely, and e-cigarettes containing caffeine (Caf) have recently become commercially available. However, no risk evaluation of these Caf-containing products has been performed to date. Such an evaluation requires a sensitive analytical method for quantifying Caf in smoke from e-cigarettes. The aim of this study was to establish a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for quantifying vaporized Caf from commercially available e-cigarettes, and to determine minor components related to Caf in cigarette smoke extract (CSE)., Methods: A sampling system for Caf using a suction pump was designed and sampling conditions were optimized., Results: The optimized LC-MS/MS conditions allowed the sensitive determination of Caf in smoke with a limit of detection of 0.03 ng/mL at a signal-to-noise ratio of 3. The method was applied to CSEs from five e-cigarette products and the concentration of Caf ranged from 0.894 ± 0.090 to 3.32 ± 0.14 μg/mL smoke (n = 3). Additionally, minor components related to Caf, such as theobromine, theophylline, and paraxanthine, were detected in CSE and in e-liquid at very low concentrations, indicating that they were impurities in e-liquid and vaporized along with Caf., Conclusion: This is the first report to determine the concentration of vaporized Caf using an LC-MS/MS method and to clarify several minor components in smoke from e-cigarettes., (© 2022. The Author(s), under exclusive licence to Japanese Association of Forensic Toxicology.)

Ubiquinone (UQ) is considered one of the important biologically active molecules in the human body. Ubiquinone determination in human plasma is important for the investigation of its bioavailability, and also its plasma level is considered an indicator of many illnesses. We have previously developed sensitive and selective chemiluminescence (CL) method for the determination of UQ in human plasma based on its redox cycle with dithiothreitol (DTT) and luminol. However, this method requires an additional pump to deliver DTT as a post-column reagent and has the problems of high DTT consumption and broadening of the UQ peak due to online mixing with DTT. Herein, an HPLC (high-performance liquid chromatography) system equipped with two types of online reduction systems (electrolytic flow cell or platinum catalyst-packed reduction column) that play the role of DTT was constructed to reduce reagent consumption and simplify the system. The newly proposed two methods were carefully optimized and validated, and the analytical performance for UQ determination was compared with that of the conventional DTT method. Among the tested systems, the electrolytic reduction system showed ten times higher sensitivity than the DTT method, with a limit of detection of 3.1 nM. In addition, it showed a better chromatographic performance and the best peak shape with a number of theoretical plates exceeding 6500. Consequently, it was applied to the determination of UQ in healthy human plasma, and it showed good recovery (≥97.9%) and reliable precision (≤6.8%) without any interference from plasma components.

Myristicin [5-allyl-1‑methoxy-2,3-(methylenedioxy)benzene] is the major constituent of the seasoning nutmeg oil and powder. Sometimes myristicin is abused via its ingestion at high doses to cause hallucination. In these high doses, myristicin could cause severe adverse health effects, including convulsion, delirium, and palpitation. Hence there is a strong need for a sensitive method for its analysis, such as fluorescence determination. Myristicin has a very weak fluorescence and also lacks derivatizable groups like the carboxylic, hydroxyl, or amino group in its structure, which makes its fluorescence derivatization challenging. In this research, we developed a fluorescence labeling method for myristicin based on the Mizoroki-Heck coupling reaction of its terminal alkene with a fluorescent aryl iodide derivative, 4-(4,5-diphenyl-1H-imidazol-2-yl)iodobenzene (DIB-I). Then, we developed an HPLC fluorescence detection method for the determination of myristicin utilizing this labeling reaction. The developed method showed a good linear response for myristicin (r = 0.995) in the range of 0.01-10 µmol/L with excellent sensitivity down to the detection limit of 2.9 nmol/L (9.6 fmol/injection). Finally, the developed method could be successfully applied to determine myristicin content in nutmeg powder, oil samples, and human plasma with simple extraction methods and good recoveries ranging from 89.3 to 106%., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022. Published by Elsevier B.V.)

A new pulse UV irradiation-induced chemiluminescence (CL) determination method was developed for l-tyrosine using the luminol derivative L-012. The proposed method depends on the formation of reactive oxygen species (ROS) upon pulse UV irradiation of l-tyrosine; then, these ROS react with L-012 producing strong CL. The proposed method showed excellent sensitivity and ultraselectivity toward l-tyrosine. The mechanism of the developed CL method was studied using ROS scavengers, HPLC, and mass spectrometry. The method was linear for l-tyrosine in the range of 0.03-50 μM. Minor changes in the l-tyrosine structure, including hydroxylation, dehydroxylation, phosphorylation, or decarboxylation, were found to lead to a strong decrease in CL. Using the excellent selectivity of the proposed method for l-tyrosine, we have developed a CL assay for measuring alkaline phosphatase activity in the range of 0.02-15 U/L with the limit of detection (LOD) of 4 mU/L using the nonchemiluminescent O -phospho-l-tyrosine as a substrate. Furthermore, the CL reaction was applied for tyrosinase activity assay as this enzyme can convert l-tyrosine to the nonchemiluminescent l-dopa. The decrease in CL is correlated with the tyrosinase activity in the range of 0.025-0.75 U/mL with an LOD of 1.5 mU/mL. Moreover, the tyrosinase activity assay was successfully applied for the determination of IC 50 of the tyrosinase inhibitors kojic acid and benzoic acid. Therefore, our novel pulse UV irradiation CL method for the determination of l-tyrosine was not only suitable for the determination of this vital amino acid but also extended to the successful determination of its producing and metabolizing enzymes and their inhibitors.

A new fluorescence derivatization technique for the determination of the thyroid hormones, 3,3',5-triiodo-L-thyronine (T 3 , triiodothyronine) and 3,3',5,5'-tetraiodo-L-thyronine (T 4 , L-thyroxine), in human serum was developed based on the Sonogashira coupling reaction. This derivatization reaction was recently utilized by our research group as a promising solution for the derivatization of ortho-substituted aryl halides that suffer from steric hindrance. T 3 and T 4 possess amino groups that could be derivatized by many reagents; however, these reagents are not useful in the case of biological analysis as they could non-selectively react with many biogenic amines and amino acids. Thus, herein we aimed at labeling the iodo-phenyl group of T 3 and T 4 as a selective fluorescence labeling approach suitable for biological analysis. The fluorescent alkyne, 2-(4-ethynylphenyl)-4,5-diphenyl-1H-imidazole (DIB-ET), can label the ortho-substituted aryl halides T 3 and T 4 in the presence of palladium and copper as catalysts, overcoming the steric hindrance of ortho-substitution. Furthermore, the application of the proposed method for the selective analysis of T 3 and T 4 in biological samples was successfully performed even in the presence of numerous biological components. The formed fluorescent derivatives produced from the reaction of DIB-ET and T 3 and T 4 could be determined by an HPLC system with fluorescence detection. The proposed method was successfully applied for the selective and sensitive determination of T 3 and T 4 in human serum with detection limits (S/N = 3) of 4.0 and 6.1 ng/mL and the recovery rate in the ranges of 84.3-92.1% and 81.3-84.9%, respectively. Therefore, the proposed method could be used as a new simple tool for the simultaneous determination of T 3 and T 4 in biological samples., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022. Published by Elsevier B.V.)

Copper (II) is one of the most important metal ions for the human body that act as a catalytic cofactor for many metalloenzymes and proteins, and its homeostasis disruption could lead to many neurological diseases. The reported probes for Cu (II) determination are mostly based on fluorescence quenching mechanism, which provides low precision and reliability. In the present work, a turn-on fluorescence probe, (Z)-1-[2-oxo-2-[2-[1-oxoaceanthrylen-2 (1H)-ylidene]hydrazinyl]ethyl]-pyridinium (OAHP), for highly selective detection of Cu 2+ was developed. Hydrazide moiety of OAHP quenches probe fluorescence; however, upon its reaction with Cu, oxidative cleavage of the hydrazide moiety and intramolecular cyclization occurs, forming oxadiazole derivative with strong fluorescent properties. In this context, OAHP displayed significant fluorescence enhancement with increasing levels of Cu 2+ . OAHP could detect Cu 2+ selectively with a detection limit of 18 nM (1.1 ppb). This is the first report for a probe that uses the ability of Cu 2+ to induce oxidative decomposition of hydrazide with intramolecular cyclization, and it showed exceptional selective performance and exquisite sensitivity. Next, the method was applied successfully for monitoring Cu 2+ in tap water samples with good accuracy (found% of 95.8-101.5%) and precisions (RSD<10%). Finally, OAHP was successfully applied for imaging Cu 2+ in living cells, and this result indicates the potential of OAHP for selective detection of Cu 2+ in complicated matrices., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Eugenols (Eugs) such as eugenol (Eug), methyleugenol (MeEug), and linalool (Lin) in basil product are the main bioactive components of basil products and have a terminal double-bond. A sensitive HPLC-fluorescence method for Eugs derivatized with 4-(4,5-diphenyl-1H-imidazol-2-yl)iodobenzene (DIBI) was developed. Good separation of DIB-Eugs was achieved within 20 min on an Atlantis T3 column (50 × 2.1 mm i.d., 3 µm) with a mobile phase of methanol-water. The calibration curves obtained with Eug standards showed good linearities in the range of 0.1-50 µM (r ≥ 0.999). The limits of detection at a signal-to-noise ratio (S/N) = 3 for Eug, MeEug, and Lin were 1.0, 6.0, and 4.8 nM, respectively. The limits of quantitation (S/N = 10) of the Eugs were lower than 19.9 nM. The accuracies for the Eugs were within 96.8-104.6%. The intra- and inter-day precisions as relative standard deviations for the Eugs were less than 1.2 and 9.6% (n = 3). The recoveries of Eug, MeEug, and Lin were 99.0 ± 0.1, 98.0 ± 0.2, and 96.0 ± 0.4% (n = 3), respectively. The DIB-Eugs were confirmed to be stable for 2 h (>90%) at room temperature and 24 h (>95%) at 4 °C. These parameters of the proposed method were useful for the simultaneous determination of Eugs in basil products. Therefore, the developed method may be a powerful tool for the quality evaluation of dried commercially available basil products.

We have developed an HPLC-UV method for the determination of pyrroloquinoline quinone (PQQ), which utilizes a redox-based colorimetric reaction. In the proposed colorimetric reaction, the redox reaction between PQQ and dithiothreitol generates superoxide anion radicals that can convert 2-(4-iodophenyl)-3-(4-nitrophenyl)-5-phenyl-2H-tetrazolium chloride (INT) to formazan dye. After PQQ separation on an octadecyl silica column, it was mixed online with dithiothreitol and INT, and the formed formazan dye was monitored by absorbance at 490 nm. The detection limit (S/N = 3) of the proposed method was 7.6 nM (152 fmol/injection). The proposed method could selectively detect PQQ in food products without any clean-up procedures.

Although benzofuran-2-boronic acid hardly emits fluorescence, it can be rapidly converted to a highly fluorescent benzofuran dimer after mixing with a palladium catalyst and amine. We found that a fluorescence enhancement accompanying dimerization was quantitatively promoted upon increasing the concentration of amine. In the present study, we developed a simple fluorescence assay for amines based on the promotive effect. As the result of a fluorescence measurement of the reaction mixture of 19 kinds of typical amines, it was found that tertiary amines including triethylamine (TEA) provided a significant fluorescence enhancement. Finally, the fluorogenic reaction could be applied to develop a high-throughput fluorescent microplate assay for TEA with the limit of detection (blank + 3SD) of 0.091 μM.

Aldehydes are toxic carbonyl compounds that are identified in various matrices surrounding us. For instance, aldehydes could be formed during the cooking and frying of foods which affects the food quality and safety. Derivatization is a must for the determination of aldehydes as they lack intrinsic chromophoric groups. 2,4-Dinitrophenyl hydrazine (DNPH) is the most used derivatizing reagent for aldehydes and the formed hydrazones could be determined by either HPLC-UV or LC-MS. However, UV detection is non-sensitive, and the MS equipment is expensive and not widely available. Thus, herein we report a smart chemiluminescence (CL) detection method for the DNPH aldehydes derivatives. These derivatives are supposed to possess photosensitization ability due to the presence of strong chromophoric structures; nitrobenzene and phenyl hydrazone. Upon their UV irradiation, singlet oxygen is found to be produced which then converts the DNPH-aldehyde derivative into hydroperoxide. Next, the hydroperoxide reacts with luminol in an alkaline medium producing a strong CL. An HPLC system with online UV irradiation and online reaction with luminol followed by CL detection was constructed and used for the determination of aldehydes after their derivatization with DNPH. The developed method showed excellent sensitivity with detection limits down to 1.5-18.5 nM. The achieved sensitivity is superior to that obtained by HPLC-UV and LC-MS detection methods for DNPH-aldehydes derivatives. Additionally, our approach is an chemiluminogenic where the DNPH reagent itself does not produce CL which is an excellent advantage. The method was applied successfully for the determination of aldehydes in canola oil samples using simple liquid-liquid extraction showing good recovery (87.0-106.0%), accuracy (87.2-106.6), and precision (RSD≤10.2%). After analysis of fresh and heated oil samples, it was demonstrated that heating of oil, even for short time, strongly elevated the level of their aldehydes' content. At last, it was found that the results of the analysis of aldehydes in oil samples using the proposed method perfectly matched those obtained by a reference LC-MS method., (Copyright © 2021 Elsevier B.V. All rights reserved.)

We herein report a case of aortitis induced by granulocyte colony-stimulating factor (G-CSF) that coincided with lung injury, splenomegaly, and cutaneous manifestations during treatment for recurrent extraosseous mucinous chondrosarcoma. Computed tomography revealed large-vessel vasculitis, splenomegaly, and pulmonary interstitial changes. Treatment with prednisolone was successful. Because sarcoma is a rare disease, this case is valuable for showing clinicians that G-CSF preparations could cause aortitis regardless of the patient's underlying diseases or therapeutic pharmacological backgrounds.

Background and Aim: Non-alcoholic steatohepatitis (NASH) is characterized by hepatic steatosis, inflammation, and hepatocellular injury with varying degrees of fibrosis. There are currently no established treatment approaches for NASH other than lifestyle interventions. Periostin, a matricellular protein required for tissue remodeling and fibrosis, plays an important role in hepatic steatosis and fibrosis and could be a potential target for NASH treatment. Advances in molecular biology and biochemical engineering have led to the development of antisense oligonucleotides (ASOs) that can inhibit target genes with no significant toxic effects. Herein, we investigated the therapeutic effects of periostin-targeting ASO (PNASO) in NASH., Methods: C57BL/6J mice were fed a choline-deficient, l-amino acid-defined, high-fat diet (CDAHFD) to induce NASH with or without intraperitoneal injection of mouse PNASO. To explore the role of periostin in hepatocellular steatosis, Hc3716 cells, an immortalized human hepatocyte line, were treated with recombinant periostin in vitro., Results: The induced periostin expression in the liver of CDAHFD-fed mice was significantly suppressed by PNASO. The deletion of hepatic periostin by PNASO significantly ameliorated hepatic steatosis while restoring the expression levels of peroxisome proliferator-activated receptor-alpha (PPAR-α) and its target genes. PNASO also inhibited hepatic fibrosis, reflected by the reduction of alpha-smooth muscle actin, collagen type I, and other fibrotic markers. In vitro experiments demonstrated that treatment with recombinant periostin increased cellular lipid accumulation in Hc3716 cells accompanied with the downregulation of PPAR-α., Conclusions: Periostin-targeting ASO is a potential therapeutic approach for the efficient treatment of hepatic steatosis and fibrosis in NASH., (© 2020 Journal of Gastroenterology and Hepatology Foundation and John Wiley & Sons Australia, Ltd.)

Purpose: Deoxycholic acid (DCA), a secondary bile acid, is reportedly increased in the serum of patients with nonalcoholic steatohepatitis and animals with experimentally induced hepatocellular carcinoma (HCC), but its contribution to malignant behaviors of HCC has not been precisely clarified. This study aimed to examine the effect of DCA on hepatic stellate cells (HSCs), a major component of nonparenchymal cells in the liver, and its subsequent indirect effect on HCC cells., Methods: LX2 cells, a human HSC line, were treated with DCA in vitro. Then, HuH7 cells, a human hepatoma cell line, were incubated in conditioned media of DCA-treated LX2 to investigate the subsequent effect focusing on malignant behaviors., Results: DCA resulted in cellular senescence in LX2 with the decreased cell proliferation via cell cycle arrest at G0/1 phase, together with the induction of senescence-associated secretory phenotype (SASP) factors. To investigate the influence of SASP factors secreted by HSCs in response to DCA, HCC cells were treated with conditioned media that promoted cell migration and invasion via induction of epithelial mesenchymal transition. These changes were attenuated in the presence of neutralizing antibody against IL8 or TGFβ. Pathological analysis of surgical specimens from HCC patients revealed that senescent HSCs were detected in the stroma surrounding HCC., Conclusion: Our data suggest an important role of HSC senescence caused by DCA for the malignant biological behaviors of HCC via induction of SASP factors, particularly IL8 and TGFβ.

We herein report on two male patients (age, 22 and 44 years) who were referred to our department with swelling of the upper right arm after attending other hospitals. Right subclavian vein thrombosis was demonstrated by ultrasonography and they were then further evaluated by contrast-enhanced computed tomography (CT). Successful treatment involved venous thrombectomy in one patient and anticoagulant therapy in the other. Paget-Schhroetter syndrome was confirmed using standard vascular ultrasonography. Despite the accuracy of this method for diagnosing Paget-Schroetter syndrome, some cases are difficult to confirm. We reviewed 29 previously published case reports of Paget-Schroetter syndrome and analyzed the patient baseline characteristics, time to diagnosis, and the diagnostic methods used.

A selective and highly sensitive high performance liquid chromatography (HPLC) with fluorescence derivatization method was developed for determination of ethinyl estradiol (EE); one of endocrine-disrupting compounds (EDCs). The fluorescence derivatization procedure was based on Sonogashira coupling reaction using 4-(4, 5-diphenyl-1H-imidazole-2-yl) iodobenzene (DIB-I), a fluorescence labeling reagent, to derivatize EE in presence of copper and palladium ions. The formed fluorescent product was separated on Cosmosil 5C 18 MS-II by an isocratic elution with a mobile phase composed of acetonitrile: 5.0 mM Tris-HNO 3 buffer, pH 7.4 (60:40, v/v %). The detection wavelengths were set at 310 and 400 nm as excitation and emission wavelengths, respectively. Various parameters affecting derivatization reaction were optimized. Further, the proposed method was validated and a good linearity with low detection limit (S/N=3) 7.4 ng L -1 was obtained in water sample after a simple solid-phase disk extraction (C 18 SPE disk) method. The proposed method was successfully applied for detection of EE in river water samples in order to monitor EE concentration and to distinguish its effect on the ecosystem and human health., Competing Interests: Declaration of Competing Interest The authors declare no conflict of interest., (Copyright © 2020. Published by Elsevier B.V.)

The long-wavelength fluorogenic derivatization method for aryl halides was developed based on stilbene formation by the Heck coupling reaction between aryl halides and vinylbenzenes in the presence of palladium(II) acetate as a catalyst. Fluorescent maximum wavelengths of the derivative obtained by the proposed reaction were 365 - 450 nm, which were 50 - 100 nm longer than those of the biphenyl derivatives formed with our previously developed fluorogenic derivatization method. Also, by the investigation using vinylbenzenes containing electron-donating or -withdrawing functional groups, it was found that an internal charge transfer system could contribute to extend the emission wavelength of the derivative. Furthermore, the proposed reaction was applied to develop a pre-column derivatization HPLC with fluorescence detection method for aryl bromides using 4-vinylanisole. p-Substituted aryl bromide derivatives (i.e., p-bromobenzonitrile, p-bromoanisole, bromobenzene, p-bromobenzoic acid ethyl ester, p-bromotoluene) were successfully detected within 40 min with the detection limit of 0.007 - 0.264 μM. Despite the short reaction time of 10 min, the reaction yields for p-bromoanisole and bromobenzene were good at 101 and 87%, respectively.

Chemiluminescence-enzyme immunoassays make it possible to measure trace components with high sensitivity and selectivity due to the high specificity of the antigen-antibody reaction and the high sensitivity of chemiluminescence assays. However, using an enzyme-labeled antibody suffers from many problems such as low reproducibility due to the instability of the enzyme and inhibition of antigen-antibody reaction due to its steric effect. Therefore, herein we report an innovative non-enzymatic chemiluminescence immunoassays labeling reagent through using quinone as a signal-generating tag coupled with biotin as a binder, to overcome enzymatic labeling problems. Biotinylated-1,4-naphthoquinone (biotin-NQ) was synthesized and characterized and it could produce long-lasting chemiluminescence upon mixing with dithiothreitol and luminol based on the redox cycle of quinone. Biotin-NQ showed exceptional stability towards different stress factors that may be encountered during performing the immunoassay such as high temperatures, highly acidic and alkaline conditions, and repeated freeze-thaw cycles. On the other hand, all these conditions lead to decreased labeling enzyme reactivity due to possible denaturation of its protein structure. Finally, the measurement of the biotin-labeled antibody was successfully performed using biotin-NQ and avidin. As a result, the antibody could be detected down to 25.7 nM which is 2.5 times sensitive than biotin-HRP chemiluminescence-enzyme immunoassays. Moreover, our method was applied successfully for determination of avidin using immobilized biotinylated antibody and biotin-NQ, which simulates immunoassays. Avidin could be detected down to 23.4 nM with excellent linearity (r = 0.996). Accordingly, our developed reagent, biotin-NQ, could be used as a universal highly stable, cost-effective, and steric free non-enzymatic label for immunoassays., Competing Interests: Declaration of competing interest All the authors declare that there is no conflict of interest., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Antioxidants have gained marked attention owing to their ability to prevent the oxidation of biological components and to protect the body from reactive oxygen species, thereby maintaining human health. Thus, antioxidant-rich dietary supplements and natural foods can be effective against oxidative stress and can even act as chemopreventive agents. Therefore, a simple and rapid assay for evaluation of antioxidant capacity and assessment of their distribution profile in natural sources is vital. Herein, we report a rapid, innovative chemiluminescence (CL) platform for evaluation and visualization of antioxidant capacity. We found that intense and long-lasting CL was formed upon the redox reaction of quinones, e.g., menadione, with antioxidants, e.g., l-ascorbic acid, in the presence of luminol. The produced CL intensities were proportional to the antioxidants' concentrations with a detection limit of 0.18 μM for the model antioxidant, l-ascorbic acid. As the formed CL was long-lasting, it could be easily captured and detected with a charge-coupled device (CCD) camera. To evaluate the quantification ability of the CCD camera, we developed a smart and fast microplate-based assay based on photographing the generated CL with a cooled CCD camera. The photographed CL intensities were linearly proportional with the antioxidant concentrations, and then the method was applied for photographing multiple food sample extracts. Ultimately, we utilized our method for the distribution profiling of antioxidant capacity in food cut sections. Samples were dipped in luminol and then in quinone, followed by CCD camera photography, without the need for any pulverization/extraction procedure, giving precise antioxidant distribution information.

Glyoxylic acid (GA) is the intermediate metabolite in various mammalian metabolic pathways. GA showed high reactivity towards formation of advanced glycation end-products (AGEs); the main cause of pathogenesis and complications of many diseases. The presented study aimed to detect GA in healthy and cardiovascular patients' (CV) sera; however analysis of GA in biological fluid is a challenge and requires chemical derivatization. Hence, a new, highly sensitive, time saving and reproducible pre-column fluorescence derivatization procedure coupled with high performance liquid chromatography (HPLC) method was developed. The derivatization method was based on reaction of 2-aminobenzenthiol (2-ABT), a fluorogenic reagent, with GA in acidic medium to form highly fluorescent thiazine derivative (290 and 390 nm for excitation and emission wavelengths respectively). The fluorescent derivative was separated within 6 min on a reversed-phase ODS column using an isocratic elution with a mixture of methanol-water (70:30, v/v%). The proposed method parameters were optimized and the method was validated. A good linearity in the concentration range (0.05-5.0 µM) was obtained with detection limit (LOD) of 10 nM (200 fmol/injection), which is more sensitive than several previous methods. Moreover, the recovery results were within the range of 85.0-95.5 % and the intra- and inter-day precision results were ≤3.5%. It should be emphasized that this method is the first one for monitoring of GA in CV patients; to investigate its role for diagnosis and monitoring the severity and complications of this disease in clinical laboratory., Competing Interests: Declaration of Competing Interest The authors declare no conflicts of interest., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Currently, LC-MS has various applications in different areas such as metabolomics, pharmacokinetics, and pathological studies. Yet, matrix effects resulting from co-existing constituents remain a major problem for LC-MS [or LC-tandem mass spectrometry (LC-MS/MS)]. Moreover, technical problems and instrumental drifts may lead to ion abundance variance. Thus, an internal standard (IS) is required to guarantee the accuracy and precision of the method. Because of their limited number, isotope-coded derivatization (ICD) has been recently introduced to overcome this problem. For ICD, a stable heavy isotope-coded moiety is used for labeling the standard or the control sample and the formed products can act as ISs. A light form of the reagent is used for labeling the sample. Then, both are mixed and analyzed by LC-MS(/MS). This strategy permits the identification of different unknown analytes including potential metabolites and disease biomarkers. All these attributes lead to persistent growth in the applications of ICD LC-MS(/MS) in various biomedical branches. In this article we review the ICD methods published in the last eight years for biomedical applications as well as briefly summarize other applications for environmental and food analyses as some of their used ICD reagents were further applied for analyzing biological specimens or have the potential for that., (© 2019 John Wiley & Sons, Ltd.)

Background: Previous findings on hepatic bile acid compositions in nonalcoholic fatty liver disease (NAFLD) have been inconsistent and complicated. The aim of this study was to investigate the effects of steatosis on hepatic bile acid composition in a hypertensive NAFLD model without obesity and diabetes mellitus and compare hepatic bile acid composition between hypertensive rats with and without steatosis., Methods: Two groups of hypertensive rats were studied: spontaneously hypertensive rats (SHR) fed with a normal diet (SHR-N) or a choline-deficient diet (SHR-CD). Two groups of normotensive rats were studied: Wistar Kyoto rats (WKY) fed a normal diet (WKY-N) or a choline-deficient diet (WKY-CD). Hepatic bile acid analysis was performed using liquid chromatography-electrospray ionization-tandem mass spectrometry., Results: Regarding bile acid composition, the hyodeoxycholic acid (HDCA) species in the SHR-CD group showed the largest change in bile acid composition, significantly decreasing to 21.9% of that found in the SHR-N group. In the WKY-CD group, no reduction of HDCA species was observed., Conclusions: We demonstrated that the decrease in HDCA species was the main alteration in a hypertensive NAFLD model. It was suggested that the decrease in HDCA species in the SHR-CD group was caused by dysbiosis., (© 2019 Japanese Society of Hepato-Biliary-Pancreatic Surgery.)

Background: Pancreaticobiliary maljunction and intrahepatic gallstones are at a high risk for biliary malignancy. Lysophosphatidylcholine (LPC) is increased in the bile of these patients, and we have previously reported that LPC-induced cytotoxicity causes senescence-associated secretory phenotype (SASP) in cholangiocytes. We aimed to determine the protective effect of phosphatidylcholine (PC) on LPC-induced cholangiocyte cytotoxicity., Methods: MMNK-1, a human immortalized cholangiocyte cell line was treated with LPC with or without PC. To assess the biological effects of SASP components on cholangiocarcinoma, HuH28 and HuCCT1 (human cholangiocarcinoma cell lines) were cultured in the conditioned media where MMNK-1 cells treated with LPC., Results: The presence of PC reduced reactive oxygen species generation and oxidative DNA damage in MMNK-1 treated with LPC. Moreover, SA-β-gal activity was markedly downregulated by PC. The secretion of SASP components, including interleukin (IL)-8, IL-6, and C-C motif chemokine ligand 2 was also substantially reduced in the presence of PC. Cellular proliferation and migration were enhanced in HuCCT1 and HuH28 cells when cultured in the conditioned media, and these observations were suppressed by simultaneous addition of PC., Conclusion: PC protects cholangiocytes against LPC-induced cytotoxicity and cellular senescence, suggesting its potential as a target for inhibiting LPC-related carcinogenesis and its promotion., (© 2019 Japanese Society of Hepato-Biliary-Pancreatic Surgery.)

The apelin receptor (APJ), a receptor for apelin and elabela/apela, induces vasodilation and vasoconstriction in blood vessels. However, the prolonged effects of increased APJ-mediated signalling, involving vasoconstriction, in smooth muscle cells have not been fully characterized. Here, we investigated the vasoactive effects of APJ gain of function under the control of the smooth muscle actin (SMA) gene promoter in mice. Transgenic overexpression of APJ (SMA-APJ) conferred sensitivity to blood pressure and vascular contraction induced by apelin administration in vivo. Interestingly, ex vivo experiments showed that apelin markedly increased the vasoconstriction of isolated aorta induced by noradrenaline (NA), an agonist for α- and β-adrenergic receptors, or phenylephrine, a specific agonist for α1-adrenergic receptor (α1-AR). In addition, intracellular calcium influx was augmented by apelin with NA in HEK293T cells expressing APJ and α1A-AR. To examine the cooperative action of APJ and α1A-AR in the regulation of vasoconstriction, we developed α1A-AR deficient mice using a genome-editing technique, and then established SMA-APJ/α1A-AR-KO mice. In the latter mouse line, aortic vasoconstriction induced by a specific agonist for α1A-AR, A-61603, were significantly less than in SMA-APJ mice. These results suggest that the APJ-enhanced response requires α1A-AR to contract vessels coordinately., (© The Author(s) 2019. Published by Oxford University Press on behalf of the Japanese Biochemical Society. All rights reserved.)

Aldehydes are very reactive carbonyl compounds that are widespread naturally. Aldehydes can be produced in vivo by oxidative reactions and are able to disturb biological functions through binding and modifying biomolecules. Thus, it is necessary to determine their levels in biological samples to estimate their possible adverse effect on human health in addition to their consideration as a biomarker for oxidative stress-related diseases. Furthermore, aldehydes have been found in foodstuffs as by-products of food processing or deterioration and their amounts in food samples were used as an indicator of its quality. Aldehydes also are widely distributed in the environment sourced from the industrial and motor vehicular exhausts and human exposure to them could bring many adverse health effects. From these viewpoints, an effective analytical method for the determination of aldehydes should be essential in various fields including biological, clinical, environmental, and food sciences. Among analytical methodologies, chromatographic determination methods should be suitable tools for the simultaneous determination of wide variety of aldehydes. Derivatization reactions are frequently applied for aldehydes to improve their detection sensitivity as most of them do not possess detectable moiety. Also, derivatization can control their retention behavior on HPLC columns. Moreover, sample pretreatment procedures for aldehydes to modify their high volatility, reactivity, polarity, and inherent instability is vital for their pre-concentration and avoiding matrix effects. In this review, chromatographic determination methods for aldehydes are summarized mainly according to the recent reports with the analytical techniques including the effective extraction and chemical derivatization. Besides, the applications for the chromatographic determination of aldehydes are summarized and significant findings obtained by the application studies are described., (Copyright © 2019 Elsevier B.V. All rights reserved.)