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Clenbuterol

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https://www.readbyqxmd.com/read/29136919/flow-batch-analysis-of-clenbuterol-based-on-analyte-extraction-on-molecularly-imprinted-polymers-coupled-to-an-in-system-chromogenic-reaction-application-to-human-urine-and-milk-substitute-samples
#1
Natalia González, Marcos Grünhut, Ivana Šrámková, Adriana G Lista, Burkhard Horstkotte, Petr Solich, Hana Sklenářová, Carolina C Acebal
A fully automated spectrophotometric method based on flow-batch analysis has been developed for the determination of clenbuterol including an on-line solid phase extraction using a molecularly imprinted polymer (MIP) as the sorbent. The molecularly imprinted solid phase extraction (MISPE) procedure allowed analyte extraction from complex matrices at low concentration levels and with high selectivity towards the analyte. The MISPE procedure was performed using a commercial MIP cartridge that was introduced into a guard column holder and integrated in the analyzer system...
February 1, 2018: Talanta
https://www.readbyqxmd.com/read/29104500/clenbuterol-induces-cell-cycle-arrest-in-c2c12-myoblasts-by-delaying-p27-degradation-through-%C3%AE-arrestin-2-signaling
#2
Min Chen, Chuncheng Liu, Meng Wang, Hong Wang, Kuo Zhang, Yu Zheng, Zhengquan Yu, Xiangdong Li, Wei Guo, Ning Li, Qingyong Meng
β2-Adrenoceptor (β2-AR) agonists promote muscle growth. The aim of this study was to elucidate some effects of the selective β2-adrenoceptor agonist clenbuterol (CLB) on myoblast proliferation. We found that CLB induces cell cycle arrest in C2C12 myoblasts. This effect is partly due to the enhanced stability of p27, rather than the increased gene transcription via cAMP response element-binding protein (CREB). Specifically, CLB treatment enhanced the accumulation of p27 in the nucleus while depleting it from the cytosol via a mechanism that requires β2-AR...
2017: International Journal of Biological Sciences
https://www.readbyqxmd.com/read/29030156/applicability-of-an-innovative-steroid-profiling-method-to-determine-synthetic-growth-promoter-abuse-in-cattle
#3
M H Blokland, E F van Tricht, L A van Ginkel, S S Sterk
A robust LC-MS/MS method was developed to quantify a large number of phase I and phase II steroids in urine. The decision limit is for most compounds lower than 1ngml(-1) with a measurement uncertainty smaller than 30%. The method is fully validated and was applied to assess the influence of administered synthetic steroids and beta-agonists on the steroidogenesis. From three animal experiments, clenbuterol, diethylstilbestrol and stanozolol, the steroid profiles in urine of bovine animals were compared before and after treatment...
November 2017: Journal of Steroid Biochemistry and Molecular Biology
https://www.readbyqxmd.com/read/28988472/quantitative-determination-of-bulk-molecular-concentrations-of-%C3%AE-agonists-in-pork-tissue-samples-by-direct-internal-extractive-electrospray-ionization-mass-spectrometry
#4
Jiaquan Xu, Shengrui Xu, Yipo Xiao, Konstantin Chingin, Haiyan Lu, Runhan Yan, Huanwen Chen
Rapid quantitative determination of bulk molecular concentration in solid samples without sample pretreatment is demonstrated using the internal extractive electrospray ionization-mass spectrometry (iEESI-MS) analysis of six β-agonists, including salbutamol (Sal), clenbuterol (Cle), ractopamine (Rac), terbutaline (Ter), tulobuterol (Tul), brombuterol (Bro), in pork tissue samples. Single sample analysis only required 1 min. The linear range of detection was about 0.01-1000 μg/kg (R(2) > 0.9994). The limit-of-detection (LOD) varied from 0...
November 7, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28874749/structural-and-pharmacological-basis-for-the-induction-of-mitochondrial-biogenesis-by-formoterol-but-not-clenbuterol
#5
Robert B Cameron, Craig C Beeson, Rick G Schnellmann
Mitochondrial dysfunction is associated with numerous acute and chronic degenerative diseases. The beta-2 adrenergic receptor (β2AR) agonist formoterol induces mitochondrial biogenesis (MB), but other β2AR agonists, such as clenbuterol, do not. We sought to identify the MB signaling pathway of formoterol and the differences in signaling between these two ligands that result in the differential induction of MB. While formoterol and clenbuterol increased cAMP, only formoterol increased the phosphorylation of Akt and its downstream target eNOS...
September 5, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28874356/impact-of-%C3%AE-adrenergic-signaling-in-pgc-1%C3%AE-mediated-adaptations-in-mouse-skeletal-muscle
#6
Nina Brandt, Lene Nielsen, Bjørg Thiellesen Buch, Anders Gudiksen, Stine Ringholm, Ylva Hellsten, Jens Bangsbo, Henriette Pilegaard
PGC-1α has been suggested to regulate exercise training-induced metabolic adaptations and autophagy in skeletal muscle. The factors regulating PGC-1α are however not fully resolved. The aim was to investigate the impact of β-adrenergic signaling in PGC-1α mediated metabolic adaptations in skeletal muscle with exercise training. Muscle was obtained from muscle specific PGC-1α knockout (MKO) mice and LOX/LOX 1) 3h after a single exercise bout with or without prior injection of propranolol or 3h after a single injection of clenbuterol and 2) after 5 weeks of wheel running exercise training with or without propranolol treatment or after 5 weeks of clenbuterol treatment...
September 5, 2017: American Journal of Physiology. Endocrinology and Metabolism
https://www.readbyqxmd.com/read/28856822/resolution-of-r-and-s-enantiomers-of-clenbuterol-in-pharmaceutical-preparations-and-black-market-products-using-liquid-chromatography-tandem-mass-spectrometry
#7
Benjamín Velasco-Bejarano, Jahir Bautista, Ma Olivia Noguez, Evangelina Camacho, Martha E Rodríguez, Leonardo Rodríguez
Several banned substances are illegally used by athletes in racemic mixtures for performance enhancement. These include clenbuterol, methyl hexaneamine, methamphetamines, and amphetamines. Clenbuterol is present in a large number of doping samples from Olympic and non-Olympic athletes that have adverse analytical findings (AAFs). In some cases, the presence of these substances could be the result of consumption of meat contaminated with clenbuterol. In other cases, the origin is not clear. In this study, 27 products with racemic clenbuterol were evaluated using a new analytical methodology for the resolution of R-(-) and S-(+)-enantiomers of clenbuterol by liquid chromatography-tandem mass spectrometry (LC-MS/MS) using a chiral column in 15 min with good separation...
August 30, 2017: Drug Testing and Analysis
https://www.readbyqxmd.com/read/28764496/microcantilever-array-instrument-based-on-optical-fiber-and-performance-analysis
#8
Guangping Zhang, Lin Wu, Chao Li, Shangquan Wu, Qingchuan Zhang
We developed a microcantilever array biosensor instrument based on optical readout from a microcantilever array in fluid environment. The microcantilever signals were read out sequentially by laser beams emitted from eight optical fibers. The optical fibers were coupled to lasers, while the other ends of the fibers were embedded in eight V-grooves with 250 μm pitch microfabricated from a Si wafer. Aspherical lens was used to keep the distance between lasers. A programmable logic controller was used to make the system work stably...
July 2017: Review of Scientific Instruments
https://www.readbyqxmd.com/read/28719814/enantiomeric-separation-of-seven-%C3%AE-agonists-by-nace-study-of-chiral-selectivity-with-diacetone-d-mannitol-boric-acid-complex
#9
Lili Lv, Lijuan Wang, Jun Li, Yajun Jiao, Shengnan Gao, Jiachang Wang, Hongyuan Yan
A rapid and effective nonaqueous capillary electrophoresis (NACE)-ultraviolet (UV) method was developed for the enantiomeric separation of seven β-agonists. Diacetone-d-mannitol-boric acid complex was used as a new chiral selector. It was in situ synthesized by the reaction of diacetone-d-mannitol and boric acid in methanol medium containing triethylamine. The effects of diacetone-d-mannitol, boric acid, and triethylamine concentrations on the enantioseparation were carefully investigated. Under the optimized conditions, baseline enantioseparation could be obtained for six of the tested β-agonists within 12min...
October 25, 2017: Journal of Pharmaceutical and Biomedical Analysis
https://www.readbyqxmd.com/read/28699480/adulteration-practices-of-psychoactive-illicit-drugs-an-updated-review
#10
Renata Solimini, Maria C Rotolo, Manuela Pellegrini, Adele Minutillo, Roberta Pacifici, Francesco P Busardò, Simona Zaami
BACKGROUND: Powdery drugs such as cocaine and heroin are frequently adulterated or diluted predominantly to obtain more doses and to increase the drug dealer's profits, but also to enhance, to modify or to oppose drug effects. The aim of this report is to provide an overview of the recent scientific literature on medicines as well as on new psychoactive substances, used as cutting agents (i.e. pharmacologically active adulterants) and on the related adverse health effects on consumers, possibly due to the synergistic effect of the adulterants laced with substances of abuse...
2017: Current Pharmaceutical Biotechnology
https://www.readbyqxmd.com/read/28698672/metabolic-effects-of-clenbuterol-and-salbutamol-on-pork-meat-studied-using-internal-extractive-electrospray-ionization-mass-spectrometry
#11
Haiyan Lu, Hua Zhang, Tenggao Zhu, Yipo Xiao, Shaoxian Xie, Haiwei Gu, Meng Cui, Liping Luo
Direct mass spectrometry analysis of metabolic effects of clenbuterol and salbutamol on pork quality at the molecular level is incredibly beneficial for food regulations, public health and the development of new anti-obesity drugs. With internal extractive electrospray ionization mass spectrometry (iEESI-MS), nutrients including creatine, amino acids, L-carnitine, vitamin B6, carnosine and phosphatidylcholines in pork tissue were identified, without sample pretreatment, using collision-induced dissociation (CID) experiments and by comparison with authentic compounds...
July 11, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28637453/electroacupuncture-at-li11-promotes-jejunal-motility-via-the-parasympathetic-pathway
#12
Xuanming Hu, Mengqian Yuan, Yin Yin, Yidan Wang, Yuqin Li, Na Zhang, Xueyi Sun, Zhi Yu, Bin Xu
BACKGROUND: Gastrointestinal motility disorder has been demonstrated to be regulated by acupuncture treatment. The mechanisms underlying the effects of acupuncture stimulation of abdominal and lower limb acupoints on gastrointestinal motility have been thoroughly studied; however, the physiology underlying the effects of acupuncture on the forelimbs to mediate gastrointestinal motility requires further exploration. The aim of this study was to determine whether electroacupuncture (EA) at LI11 promotes jejunal motility, whether the parasympathetic pathway participates in this effect, and if so, which somatic afferent nerve fibres are involved...
June 21, 2017: BMC Complementary and Alternative Medicine
https://www.readbyqxmd.com/read/28634884/a-nanosensor-based-on-carbon-dots-for-recovered-fluorescence-detection-clenbuterol-in-pork-samples
#13
Yalan Liu, Qiujun Lu, Xiaojun Hu, Haiyan Wang, Haitao Li, Youyu Zhang, Shouzhuo Yao
Clenbuterol (CLB), a member of β-agonist family, has now been a serious threat to human health due to its illegal usage in the animal feed. In this paper, we designed a fluorescence resonance energy transfer (FRET) system consisting of carbon dots (C-dots) and gold nanoparticles (AuNPs) for recovered fluorescence detecting of CLB. In the presence of CLB, CLB molecules can interact with AuNPs via Au-N bonds, preventing the interaction of C-dots and AuNPs, which induced the recover of the fluorescent intensity...
June 20, 2017: Journal of Fluorescence
https://www.readbyqxmd.com/read/28633284/determination-of-some-%C3%AE-blockers-and-%C3%AE-2-agonists-in-plasma-and-urine-using-liquid-chromatography-tandem-mass-spectrometry-and-solid-phase-extraction
#14
Alaa A Salem, Ibrahim Wasfi, Salama S Al-Nassib, Mahmoud Allawy Mohsin, Nawal Al-Katheeri
A highly sensitive method for the determinations of acebutolol, clenbuterol, nadolol, oxprenolol, propranolol, terbutaline and timolol β-blockers and β2-agonists in plasma and urine was developed. The method was optimized using electrospray ionization liquid chromatography-tandem mass spectrometry (LC-ESI-MS-MS) and clean screen solid phase extraction cartridges. Matrix effect was reduced by removing co-extractives from the SPE cartridges using methanol prior to drugs' elution. Using blood and serum matrices for calibration and applying the internal standard method has also contributed to the reduction of matrix effect...
September 1, 2017: Journal of Chromatographic Science
https://www.readbyqxmd.com/read/28618339/hplc-ms-ms-method-for-troventol-determination-in-human-plasma-and-its-application-to-biological-samples
#15
Aleksandra Nikitina, Alexander Grigoriev, Alla Sidorova
For the first time, an HPLC-MS/MS method for the determination pmol/l levels of troventol (TRV) and clenbuterol as an internal standard (IS) in human plasma was developed, validated and tested on biological samples. The method included solid phase extraction by Waters Oasis WCX cartridges and chromatographic separation on a YMC-Pack SIL (100mm×2.1mm, 5μm, 12nm) analytical column with acetonitrile-water-formic acid (50:50:0.1, v/v/v) as the mobile phase; the selected ion transitions were m/z 332.2→138.2 and m/z 277...
September 5, 2017: Journal of Pharmaceutical and Biomedical Analysis
https://www.readbyqxmd.com/read/28602280/mechanism-of-surface-plasmon-resonance-sensing-by-indirect-competitive-inhibition-immunoassay-using-au-nanoparticle-labeled-antibody
#16
Dulal C Kabiraz, Kinichi Morita, Kazuhira Sakamoto, Toshikazu Kawaguchi
We investigated the use of a surface plasmon resonance (SPR) biosensor using an antibody (Ab) labeled with Au-nanoparticle (Ab-AuNP conjugate). As clenbuterol is a small molecule, an indirect competitive inhibition immunoassay was used. The SPR immunoassay using Ab-AuNP conjugate had an extremely low limit of the detection (LOD) with a magnitude of 0.05 ppt (0.05pgmL(-1)), which was 40 times lower than that of unlabeled Ab. To identify the key factor in determining the LOD of the indirect competitive inhibition immunoassay, affinity constants of the surface immunoreaction (K1) and of the premixed solution (αK2) were evaluated...
September 1, 2017: Talanta
https://www.readbyqxmd.com/read/28578076/%C3%AE-1-and-%C3%AE-2-adrenergic-receptor-stimulation-differ-in-their-effects-on-pgc-1%C3%AE-and-atrogin-1-mafbx-gene-expression-in-chick-skeletal-muscle
#17
COMPARATIVE STUDY
Saki Shimamoto, Daichi Ijiri, Mana Kawaguchi, Kazuki Nakashima, Osamu Tada, Hiroki Inoue, Akira Ohtsuka
Adrenaline changes expression of the genes encoding peroxisome proliferator-activated receptor-gamma coactivator-1 alpha (PGC-1α), which is known as a regulator of muscle size, and atrogin-1/muscle atrophy F-box (MAFbx), which is a muscle-specific ubiquitin ligase. However, the subtype of β-adrenergic receptor (β-AR) involved in regulating these genes in skeletal muscle is not yet well defined. In this study, the effects of intraperitoneal injection of adrenaline and three β1-3-AR selective agonists on chick skeletal muscle metabolism were examined, to evaluate the functions of β-AR subtypes...
September 2017: Comparative Biochemistry and Physiology. Part A, Molecular & Integrative Physiology
https://www.readbyqxmd.com/read/28544353/chiral-separation-of-12-pairs-of-enantiomers-by-capillary-electrophoresis-using-heptakis-2-3-diacetyl-6-sulfato-%C3%AE-cyclodextrin-as-the-chiral-selector-and-the-elucidation-of-the-chiral-recognition-mechanism-by-computational-methods
#18
Yaqi Yao, Peilu Song, Xiaoli Wen, Miaoduo Deng, Jian Wang, Xingjie Guo
Chiral separation of 12 pairs of basic analyte enantiomers including oxybutynin, bambuterol, tradinterol, clenbuterol, clorprenaline, terbutaline, tulobuterol, citalopram, phencynonate, fexofenadine, salbutamol and penehyclidine was conducted by capillary electrophoresis using a single-isomer anionic β-cyclodextrin derivative, heptakis-(2,3-diacetyl-6-sulfato)-β-cyclodextrin as the chiral selector. Parameters influencing separation were studied, including background electrolyte pH, heptakis-(2,3-diacetyl-6-sulfato)-β-cyclodextrin concentration, buffer concentration and separation voltage...
May 24, 2017: Journal of Separation Science
https://www.readbyqxmd.com/read/28535735/clenbuterol-attenuates-herg-channel-by-promoting-the-mature-channel-degradation
#19
Ling Luo, Peijing Hu, Changqing Miao, Aiqun Ma, Tingzhong Wang
Clenbuterol, a β2-selective adrenergic receptor agonist, is illicitly used in weight loss and performance enhancement and animal production. Increasing evidence demonstrates that clenbuterol induces various kinds of arrhythmias and QTc interval prolongation. However, little is known about the underlying mechanism. Most drugs are associated with QTc prolongation through interfering with human ether-a-go-go-related gene (hERG) K(+) channels. The present study aims to investigate the effects and underlying mechanisms of clenbuterol on the hERG channel...
July 2017: International Journal of Toxicology
https://www.readbyqxmd.com/read/28453289/identification-of-buctopamine-and-mebuctopamine-a-%C3%AE-2-receptor-agonist-and-its-metabolite-in-swine-hair-and-feed-additives
#20
Ying-Heng Chen, Chia-Ying Yang, Chih Wen Cheng, Yi-Ying Lin, Su Lien Kuo, Ling-Wei Hsin
4-[2-(t-Butylamino)-1-hydroxyethyl]phenol (buctopamine, 4), a new β2 receptor agonist (β2-agonist), was found to be an adulterant in feed additives for swine in Taiwan, where using β2-agonists in food-production animals is prohibited. Buctopamine and its metabolite, 4-[2-(t-butylamino)-1-hydroxyethyl]-2-methoxyphenol (mebuctopamine, 2), were detected in swine hair specimens. Authentic compounds 2 and 4 were synthesized with 98.6% and 97.7% purity, respectively, as reference standards for analysis, and both compounds were more hydrophilic than ractopamine and clenbuterol...
May 17, 2017: Journal of Agricultural and Food Chemistry
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