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European Journal of Sport Science Jun 2024Citrulline malate (CM) is purported to be an ergogenic aid during various types of exercise performance. However, the effects of CM on repeated sprint performance (RSP)... (Randomized Controlled Trial)
Randomized Controlled Trial
Citrulline malate (CM) is purported to be an ergogenic aid during various types of exercise performance. However, the effects of CM on repeated sprint performance (RSP) are under-explored. In a placebo-controlled, double-blind, counterbalanced cross-over design, male university-level team sport athletes (n = 13) performed two familiarization trials, after which CM or placebo (PLA) (8 × 1 g tablets each day) were taken on the 2 days prior to, and with breakfast on the morning of, each main experimental trial. The main experimental trials employed a RSP protocol consisting of 10 repetitions of 40 m maximal shuttle run test (MST) with a 30 s interval between the start of each sprint. Sprint times and heart rate were recorded throughout the MST, and blood lactate concentrations were measured before, immediately after, and 5 min after completing the MST. CM resulted in better RSP compared to PLA, as indicated by a lower sprint performance decrement (S: CM, 4.68% ± 1.82% vs. PLA, 6.10% ± 1.83%; p = 0.03; ES = 0.77), which was possibly influenced by the fastest sprint time being faster in CM (CM, 8.16 ± 0.34 s vs. PLA, 8.29 ± 0.39 s; p = 0.011; ES = 0.34). There were no differences between CM and PLA in average sprint time (p = 0.54), slowest sprint time (p = 0.48), blood lactate concentrations (p = 0.73) or heart rate (p = 0.18), nor was there a condition × time interaction effect across the 10 sprints (p = 0.166). Three days of CM supplementation (8 g daily) attenuated the sprint performance decrement during short-duration high-intensity exercise in the form of running RSP in male university-level team sport athletes.
Topics: Humans; Male; Running; Athletic Performance; Cross-Over Studies; Double-Blind Method; Young Adult; Citrulline; Dietary Supplements; Heart Rate; Lactic Acid; Malates; Athletes; Team Sports; Performance-Enhancing Substances; Adult
PubMed: 38874989
DOI: 10.1002/ejsc.12090 -
Proceedings of the National Academy of... Jun 2024The fat mass and obesity-associated fatso (FTO) protein is a member of the Alkb family of dioxygenases and catalyzes oxidative demethylation of N-methyladenosine (mA),...
The fat mass and obesity-associated fatso (FTO) protein is a member of the Alkb family of dioxygenases and catalyzes oxidative demethylation of N-methyladenosine (mA), N-methyladenosine (mA), 3-methylthymine (mT), and 3-methyluracil (mU) in single-stranded nucleic acids. It is well established that the catalytic activity of FTO proceeds via two coupled reactions. The first reaction involves decarboxylation of alpha-ketoglutarate (αKG) and formation of an oxyferryl species. In the second reaction, the oxyferryl intermediate oxidizes the methylated nucleic acid to reestablish Fe(II) and the canonical base. However, it remains unclear how binding of the nucleic acid activates the αKG decarboxylation reaction and why FTO demethylates different methyl modifications at different rates. Here, we investigate the interaction of FTO with 5-mer DNA oligos incorporating the mA, mA, or mT modifications using solution NMR, molecular dynamics (MD) simulations, and enzymatic assays. We show that binding of the nucleic acid to FTO activates a two-state conformational equilibrium in the αKG cosubstrate that modulates the O accessibility of the Fe(II) catalyst. Notably, the substrates that provide better stabilization to the αKG conformation in which Fe(II) is exposed to O are demethylated more efficiently by FTO. These results indicate that i) binding of the methylated nucleic acid is required to expose the catalytic metal to O and activate the αKG decarboxylation reaction, and ii) the measured turnover of the demethylation reaction (which is an ensemble average over the entire sample) depends on the ability of the methylated base to favor the Fe(II) state accessible to O.
Topics: Alpha-Ketoglutarate-Dependent Dioxygenase FTO; Ketoglutaric Acids; Iron; Humans; Substrate Specificity; Adenosine; Protein Conformation; Uracil; Molecular Dynamics Simulation; Thymine
PubMed: 38865275
DOI: 10.1073/pnas.2404457121 -
Luminescence : the Journal of... Jun 2024In this study, a chemiluminescence (CL) method was developed to determine diphenoxylate in tablets and human plasma. This is the first CL method proposed to determine...
In this study, a chemiluminescence (CL) method was developed to determine diphenoxylate in tablets and human plasma. This is the first CL method proposed to determine diphenoxylate. Creating three-dimensional data caused the parallel factor analysis algorithm (PARAFAC) to be used for the first time in CL methods. The method is based on the fact that diphenoxylate enhances the weak CL produced in the reaction of Ru(phen) and acidic Ce(IV), and the concentration of Ce(IV) solution has a different effect on the CL response of diphenoxylate and the blank plasma. The calibration curve was linear from 4.0 × 10 to 1.6 × 10 mol L (R = 0.9954), and the detection limit was 1.3 × 10 mol L (S/N = 3). The sampling rate was about 30 samples per hour, and the % RSD for 10 repeated measurements of 4 × 10 mol L diphenoxylate was 5.4%. The interference effects of some ions, amino acids, and common additives were also investigated. The CL method was successfully used to determine diphenoxylate in tablets, and the results were statistically confirmed by the reference method. The proposed CL method and the PARAFAC algorithm were successfully used to determine the concentration of diphenoxylate in human blood plasma samples.
Topics: Humans; Tablets; Luminescent Measurements; Luminescence; Limit of Detection; Algorithms; Oxalates; Factor Analysis, Statistical
PubMed: 38859619
DOI: 10.1002/bio.4805 -
Journal of Chromatography. A Aug 2024The histamine H1 receptor (H1R) plays a pivotal role in allergy initiation and undergoes the necessity of devising a high-throughput screening approach centered on H1R...
The histamine H1 receptor (H1R) plays a pivotal role in allergy initiation and undergoes the necessity of devising a high-throughput screening approach centered on H1R to screen novel ligands effectively. This study suggests a method employing styrene maleic acid (SMA) extraction and His-tag covalent bonding to immobilize H1R membrane proteins, minimizing the interference of nonspecific proteins interference while preserving native protein structure and maximizing target exposure. This approach was utilized to develop a novel material for high-throughput ligand screening and implemented in cell membrane chromatography (CMC). An H1R-His-SMALPs/CMC model was established and its chromatographic performance (selectivity, specificity and lifespan) validated, demonstrating a significant enhancement in lifespan compared to previous CMC models. Subsequently, this model facilitated high-throughput screening of H1R ligands in the compound library and preliminary activity verification of potential H1R antagonists. Identification of a novel H1R antagonist laid the foundation for further development in this area.
Topics: Ligands; Maleates; High-Throughput Screening Assays; Receptors, Histamine H1; Humans; Histidine; Animals; Immobilized Proteins; CHO Cells; Membrane Proteins; Histamine H1 Antagonists; Polystyrenes; Cricetulus; Oligopeptides
PubMed: 38857565
DOI: 10.1016/j.chroma.2024.465057 -
Methods in Molecular Biology (Clifton,... 2024Structural studies require the production of target proteins in large quantities and with a high degree of purity. For membrane proteins, the bottleneck in determining...
Structural studies require the production of target proteins in large quantities and with a high degree of purity. For membrane proteins, the bottleneck in determining their structure is the extraction of the target protein from the cell membranes. A detergent that improperly mimics the hydrophobic environment of the protein of interest can also significantly alter its structure. Recently, using lipodiscs with styrene-maleic acid (SMA), copolymers became a promising strategy for the purification of membrane proteins. Here, we describe in detail the one-step affinity purification of potassium ion channels solubilized in SMA and sample preparation for future structural studies.
Topics: Maleates; Potassium Channels; Polystyrenes; Chromatography, Affinity; Styrene; Polymers; Detergents; Humans
PubMed: 38856895
DOI: 10.1007/978-1-0716-3818-7_4 -
Acta Crystallographica Section B,... Jun 2024A new Zn coordination polymer (CP) based on 2,3-pyrazine dicarboxylic acid (Hpzdc) and 4,4'-bipyridine (bpy) (ZCP) was synthesized using a facile slow evaporation...
A new Zn coordination polymer (CP) based on 2,3-pyrazine dicarboxylic acid (Hpzdc) and 4,4'-bipyridine (bpy) (ZCP) was synthesized using a facile slow evaporation method. Single-crystal X-ray diffraction revealed that ZCP is a two-dimensional porous CP, [Zn(pzdc)(bpy)(HO)], with van der Waals forces as the dominant interaction within its layers forming a 6 network. Employing energetic ultrasound irradiation, nanoscale ZCP (nZCP) was successfully synthesized and Eu ions were incorporated within its host lattice (Eu@nZCP). The resulting platform exhibits superior fluorescence characteristics and demonstrates notable optical durability. Therefore, it was used as a dual detection fluorescent sensing platform for the detection of mercury and L-cysteine (L-Cys) in aqueous media through a turn-off/on strategy. In the turn-off process, the fluorescence emission of Eu@nZCP progressively quenches by the addition of Hg via a photo-induced electron transfer (PET) mechanism. The fluorescence of Eu@nZCP is quenched to establish a low fluorescence background through the incorporation of Hg. This devised turn-on fluorescent system is suitable for the recognition of L-Cys (based on the strong affinity of L-Cys to the Hg ion) through a quencher detachment mechanism. This method attained a relatively wide linear range, spanning from 0.001 to 25 µM, with the low detection limit of 5 nM for the sensing of Hg. Also, the corresponding limit of detection (LOD) for L-Cys is 8 nM in a relatively wide linear range, spanning from 0.001 to 40 µM.
PubMed: 38856649
DOI: 10.1107/S2052520624003019 -
Dalton Transactions (Cambridge, England... Jun 2024A hydrogen-bonded three-dimensional porous metal-organic framework [Mg(HPCD)(HO)]·2HO (denoted as Mg-MOF·2HO; HPCD =...
A hydrogen-bonded three-dimensional porous metal-organic framework [Mg(HPCD)(HO)]·2HO (denoted as Mg-MOF·2HO; HPCD = 9-(2-(ethoxy(hydroxy)phosphonyl)ethyl)-9-carbazole-3,6-dicarboxylic acid) was synthesized by the reactions of HPCD and Mg(II) under solvothermal conditions. The free carboxylate group was maintained in the pore surface by adjusting the acidic reaction conditions. The highly stable Mg-MOF exhibits excellent performance for lead(II) sensing and removal from aqueous solutions.
PubMed: 38856195
DOI: 10.1039/d4dt01014k -
International Journal of Nanomedicine 2024Acne vulgaris is a chronic inflammatory skin disorder centered on hair follicles, making hair follicle-targeted delivery of anti-acne drugs a promising option for acne...
PURPOSE
Acne vulgaris is a chronic inflammatory skin disorder centered on hair follicles, making hair follicle-targeted delivery of anti-acne drugs a promising option for acne treatment. However, current researches have only focused on the delivering to healthy hair follicles, which are intrinsically different from pathologically clogged hair follicles in acne vulgaris.
PATIENTS AND METHODS
Azelaic acid (AZA) micro/nanocrystals with different particle sizes were prepared by wet media milling or high-pressure homogenization. An experiment on AZA micro/nanocrystals delivering to healthy hair follicles was carried out, with and without the use of physical enhancement techniques. More importantly, it innovatively designed an experiment, which could reveal the ability of AZA micro/nanocrystals to penetrate the constructed clogged hair follicles. The anti-inflammatory and antibacterial effects of AZA micro/nanocrystals were evaluated in vitro using a RAW264.7 cell model stimulated by lipopolysaccharide and a Cutibacterium acnes model. Finally, both the anti-acne effects and skin safety of AZA micro/nanocrystals and commercial products were compared in vivo.
RESULTS
In comparison to commercial products, 200 nm and 500 nm AZA micro/nanocrystals exhibited an increased capacity to target hair follicles. In the combination group of AZA micro/nanocrystals and ultrasound, the ability to penetrate hair follicles was further remarkably enhanced ( value up to 9.6). However, toward the clogged hair follicles, AZA micro/nanocrystals cannot easily penetrate into by themselves. Only with the help of 1% salicylic acid, AZA micro/nanocrystals had a great potential to penetrate clogged hair follicle. It was also shown that AZA micro/nanocrystals had anti-inflammatory and antibacterial effects by inhibiting pro-inflammatory factors and Cutibacterium acnes. Compared with commercial products, the combination of AZA micro/nanocrystals and ultrasound exhibited an obvious advantage in both skin safety and in vivo anti-acne therapeutic efficacy.
CONCLUSION
Hair follicle-targeted delivery of AZA micro/nanocrystals provided a satisfactory alternative in promoting the treatment of acne vulgaris.
Topics: Acne Vulgaris; Animals; Mice; Dicarboxylic Acids; Hair Follicle; RAW 264.7 Cells; Nanoparticles; Anti-Bacterial Agents; Humans; Particle Size; Anti-Inflammatory Agents; Drug Delivery Systems; Skin
PubMed: 38855733
DOI: 10.2147/IJN.S459788 -
Journal of Pharmaceutical and... Sep 2024A long-term stability study using high performance liquid chromatography (HPLC) revealed an unidentified impurity in the bromhexine hydrochloride injection, which was...
A long-term stability study using high performance liquid chromatography (HPLC) revealed an unidentified impurity in the bromhexine hydrochloride injection, which was employed as a mucolytic agent. Investigations into stress degradation and elemental impurities revealed one of the elemental impurities Fe in this injection as the primary generator of these impurities. This impurity, named N-carboxymethyl bromhexine, was a product formed during drug-excipient interaction between bromhexine and tartaric acid with Fe. The structure of the impurity was identified through ultra-high-performance liquid chromatography with diode array detector (UHPLC-DAD), liquid chromatograph mass spectrometer (LC-MS). Further, the formation mechanism of the impurity was discussed. Overall, this study elucidates the cause, origin, and mechanism of an unknown impurity in bromhexine hydrochloride injection, providing a basis for quality control for bromhexine hydrochloride injections and drug products containing both amine and tartaric acid.
Topics: Bromhexine; Drug Contamination; Chromatography, High Pressure Liquid; Excipients; Tartrates; Mass Spectrometry; Drug Stability; Quality Control
PubMed: 38850847
DOI: 10.1016/j.jpba.2024.116256 -
Bioorganic Chemistry Aug 2024The notable characteristics of recently emerged Antibody-Drug Conjugates (ADCs) encompass the targeting of Human Epidermal growth factor Receptor 2 (HER2) through...
The notable characteristics of recently emerged Antibody-Drug Conjugates (ADCs) encompass the targeting of Human Epidermal growth factor Receptor 2 (HER2) through monoclonal antibodies (mAbs) and a high ratio of drug to antibody (DAR). The achievements of Kadcyla® (T-DM1) and Enhertu® (T-Dxd) have demonstrated that HER2-targeting antibodies, such as trastuzumab, have shown to be competitive in terms of efficacy and price for development. Furthermore, with the arrival of T-Dxd and Trodelvy®, high-DAR (7-8) ADCs, which differ from the moderate DAR (3-4) ADCs that were formerly regarded as conventional, are being acknowledged for their worth. Following this trend of drug development, we endeavored to develop a high-DAR ADC using a straightforward approach involving the utilization of DM1, a highly potent substance, in combination with the widely recognized trastuzumab. To achieve a high DAR, DM1 was conjugated to reduced cysteine through the simple design and synthesis of various dimaleimide linkers with differing lengths. Using LC and MS analysis, we have demonstrated that our synthesis methodology is uncomplicated and efficacious, yielding trastuzumab-based ADCs that exhibit a remarkable degree of uniformity. These ADCs have been experimentally substantiated to exert an inhibitory effect on cancer cells in vitro, thus affirming their value as noteworthy additions to the realm of ADCs.
Topics: Humans; Immunoconjugates; Receptor, ErbB-2; Ado-Trastuzumab Emtansine; Trastuzumab; Molecular Structure; Cell Proliferation; Drug Screening Assays, Antitumor; Maleimides; Dose-Response Relationship, Drug; Antineoplastic Agents; Structure-Activity Relationship; Maytansine; Cell Line, Tumor; Antineoplastic Agents, Immunological
PubMed: 38850783
DOI: 10.1016/j.bioorg.2024.107504