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Smoking during lactation harmfully affects the amount and constituents of breast milk. Infants who consume breast milk containing miR-210-5p may have a higher risk of brain-related diseases. We investigated whether smoking during lactation decreases β-casein concentrations in milk and whether miR-210-5p expression is involved in smoking-induced β-casein suppression. During lactation, maternal CD1 mice were exposed to cigarette smoke (1.7 mg of tar and 14 mg of nicotine) in a smoke chamber for 1 h twice/day for five consecutive days. Control mice were placed in an air-filled chamber equivalent in size to the smoke chamber, with maternal separation times identical to those of the smoked mice. Maternal exposure to smoke during lactation significantly decreased β-casein expression in the mammary epithelia of smoked mice compared to that of the control mice. Signal transducer and activator transcription 5 (STAT5) and phosphorylated STAT5 (pSTAT5) are transcription factors involved in β-casein expression. In the mammary epithelia of smoked mice, the pSTAT5 and STAT5 levels were significantly lower, and miR-210-5p expression was significantly higher than that of the control mice. The β-casein, pSTAT5, and STAT5 protein levels of miR-210-5p mimic-transfected human mammary epithelial MCF-12A cells were significantly lower than those of control siRNA-transfected cells. These results indicate that smoke exposure led to an increase in miR-210-5p expression in mammary epithelium and a decrease in pSTAT5 and β-casein protein levels through the inhibition of STAT5 expression. Moreover, nicotine treatment decreased β-casein protein levels and increased miR-210-5p expression in non-malignant human mammary epithelial MCF-12A cells in a concentration-dependent manner, demonstrating that nicotine significantly affects the β-casein and miR-210-5p levels of breast milk. These results highlight the adverse effects of smoking on breast milk, providing essential information for healthcare professionals and general citizens., Competing Interests: The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Takeshi Chiba reports financial support was provided by Japanese Society for the Promotion of Science. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)

A novel pretreatment method, which was performed using a two-dimensional high-performance liquid chromatography (2D-HPLC) system, was proposed for the direct analysis of drugs in human serum. A temperature-responsive column was used as a pretreatment column. The stationary phase of the temperature-responsive column exhibits temperature-regulated hydrophilic/hydrophobic characteristics. Controlling the ionic strength of the eluent enables human serum albumin (HSA) to pass through the column without retention. When serum samples containing barbiturates or benzodiazepines were injected into the temperature-responsive column using 10 mM of ammonium acetate (pH 6.5) as the mobile phase and in the temperature range of 10-40 °C, HSA was eluted from the column near the dead time, followed by the individual drugs. When the column temperature was changed, the retention times of the drugs were altered owing to surface property changes within the pretreatment column. These closely eluted compounds were subsequently introduced into the analytical column using a column-switching valve, with a minimal gap time to avoid foreign substance contamination. This new 2D-HPLC method afforded high-quality chromatograms of multiple drugs without unwanted peaks from foreign substances. The present technique could be an attractive choice in selecting the analytical method for drug analysis.

Chiral capillary electrophoresis/tandem mass spectrometry (CE/MS/MS) using a chemically modified capillary containing sulfonated groups was developed for the following 8 amphetamine-type stimulants (ATS): amphetamine, methamphetamine (MA), norephedrine, norpseudoephedrine, ephedrine (EP), pseudoephedrine (pEP), dimethylamphetamine and methylephedrine. The running buffer was 10 mM formic acid containing 20 mM highly sulfated γ-cyclodextrin (pH 2.5) as the chiral selector. All 16 enantiomers were well resolved within 60 min, and precisely identified due to their characteristic mass spectra. Further, the RSDs of the migration times of the analytes were no more than 0.3% without any standardization. (1R,2S)-(-)-EP and (1S,2S)-(+)-pEP, which are important ATS impurities originating in the precursors, were added to a highly concentrated MA solution (1 mg/mL) and analyzed as mock samples for MA impurity analysis. Acceptable repeatability of the migration times of (-)-EP and (+)-pEP (ca. 0.3% RSDs) was still observed without interference from the large amount of MA. The limits of detection (LOD) of (-)-EP and (+)-pEP were approximately 2 μg/mL, therefore, their LOD as the impurity concentrations were calculated at about 0.2%. Seized MA samples were dissolved in water at a high concentration (1 mg/mL) and analyzed by this method. (-)-EP and (+)-pEP were clearly detected as impurities. Although these compounds had similar migration times and mass spectral patterns, the fine repeatability allowed easy identification of the impurities by a simple comparison of the absolute migration times of the specimens and those of authentic standards. This study is the first to report the use of a chemically modified capillary for the impurity profiling on CE/MS/MS., (Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.)

We examined the applicability of chemically modified capillaries on the chiral capillary electrophoresis of essential compounds for methamphetamine (MA) profiling (MA, amphetamine, ephedrine, pseudoephedrine, norephedrine, and norpseudoephedrine) using highly sulfated γ-cyclodextrin as a chiral selector. Four types of chemically modified capillaries, namely, FunCap-CE/Type D (possessing diol groups), Type A (amino groups), Type C (carboxyl groups), and Type S (sulfate groups), were evaluated. Repeatability, speed, and good chiral resolution sufficient for routine MA profiling were achieved with the Type S capillary., (Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.)

Analogs of methcathinone (MC), a psychoactive stimulant, are in circulation all over the world. These analogs have been assumed to be unstable in alkaline solutions, as is MC itself. The aims of this study were: (i) to identify the degradation products of 4-methylmethcathinone (4-MMC), a typical MC analog, in solution at pH 12 and to determine the degradation pathway, (ii) to investigate the effects of antioxidants such as l-ascorbic acid and sodium sulfite on the degradation of 4-MMC, and (iii) to investigate the stability of seven MC analogs (4-MMC, 4-, 3-, or 2-fluoromethcathinone, 4-methoxymethcathinone, N-ethylcathinone, and N,N-dimethylcathinone) in solutions at different pHs.1-(4-Methylphenyl)-1,2-propanedione (MPPD), 4-methylbenzoic acid (MBA), N,4-dimethylbenzamide (DMBA), and N-acetyl-4-MMC (N-Ac-4-MMC) were identified as the degradation products of 4-MMC in pH 12 solution by gas chromatography-mass spectrometry. There are two degradation pathways for 4-MMC as follows: (a) 4-MMC→MPPD→MBA→DMBA and (b) 4-MMC→N-Ac-4-MMC. Oxidants such as dissolved oxygen were presumed to be involved in this degradation based on the suppressive effects generated by the addition of antioxidants. All of the seven MC analogs tested were stable in acidic (pH 4) solution but degraded in neutral-to-basic solutions. Their degradation rates increased with increasing pH, and varied with their chemical structures. These findings will be very useful for not only forensic analysis but also future pharmacokinetic analysis., (Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.)

A trace amount of vegetable oil was picked up with solid-phase microextraction (SPME) fiber and identified using a gas chromatograph-mass spectrometer (GC-MS). Unsaponifiable constituents such as sterols could be detected by an injection of the SPME fiber, with the fiber touching the vegetable oil and then leading directly into the port of the GC-MS. After thermal desorption of unsaponifiable constituents, the remaining triacylglycerols or oil that was freshly added to the fiber were recovered with a little organic solvent, and the profiles of the fatty acids that had been constructing the acylglycerols were determined using a base-catalyzed trans-esterification method which produced fatty acid methyl esters. The simple and rapid techniques that make up this method make it possible to significantly reduce the preparation time and as well as the required sample volume. When urgent discrimination is required with high accuracy, this technique could serve as a useful and powerful tool for identification of vegetable oil.

During an analysis of DNA enzymes by gel electrophoresis, we found that some DNA enzymes can adopt more than one conformation. The DNA enzyme Dz31 that formed more than one conformer contained a stretch of G residues. Further investigations, involving kinetic analysis and measurements of circular dichroism, indicated that this DNA enzyme and its derivatives formed G-quadruplexes. Moreover, we found that some derivative oligomers were capable of forming dimeric G-quadruplexes. We also compared the catalytic activities of Dz31 and its mutant derivatives. The present findings suggest that DNA enzymes with five or more continuous G residues are less favorable than those without G5 in the association step in the enzymatic reaction and, thus, the choice of targets that contain a continuous stretch of C residues downstream of the cleavage site should be avoided. In addition, we found that negative charge-charge repulsion disrupted the dimerization of G-quadruplexes when a phosphate group was added directly to the 5'-terminal G of oligomers with continuous guanosine residues. In the case of 5'-phosphorylated G5CTA, direct attachment of a phosphate group to the continuous G5 sequence inhibited dimerization of G-quadruplexes, at least during electrophoresis on a denaturing gel.