Effects of 105 traditional Chinese medicines on the detection ofβ-agonists in medicine extracts and swine urine based on colloidal gold immunochromatographic assay

Colloidal gold immunochromatographic assay(CGIA)is commonly used for the on-site detection ofβ-agonists that are sometimes used illegally as feed additives in swine diets.However,few studies have evaluated the causes of false-positive results that sometimes occur when applying CGIA in agricultural settings.In this study,we investigated if this false-positive phenomenon is related to the addition of certain traditional Chinese medicines(TCMs)to swine feed.We established and verified an extraction method for TCMs,and then applied CGIA to detectβ-agonists in the extracts of 105 TCMs and in the urine of swine dosed with TCMs,respectively.Liquid chromatography-tandem mass spectrometry was used to validate the results of the urine samples tested positive forβ-agonists using CGIA.The results were also verified using TCMs and colloidal gold test strips produced by different manufacturers.The extracts of Citri Reticulatae Pericarpium Viride,Citri Reticulatae Pericarpium,Magnoliae Officinalis Cortex,Chaenomelis Fructus,and Rhodiolae Crenulatae Radix Et Rhizoma were tested positive forβ-agonists.Meanwhile,the addition of Citri Reticulatae Pericarpium Viride and Citri Reticulatae Pericarpium to swine feed resulted in false-positive results forβ-agonists in swine urine.The results provide a new way to explain false-positive CGIA results and provide valuable information for livestock feeding programs.

气相色谱-质谱法测定肝、肾和肉中β_2-受体激动剂残留量

本文用气相色谱-质谱法同时测定肝、肾和肉中β-受体激动剂中1O种βr受体激动剂残留.样品经粉碎、酶水解、沉淀蛋白质、液-液分配后,经SCX柱净化和TMS衍生化后,用美托洛尔(metoprolol)为内标,GC-MS测定.可同时测定11种βr受体激动剂,检出限为0.002mg/kg.……

Solubilities of Cimaterol and Mabuterol in SF-CO_2

The solubilities of two β-agonists, cimaterol and mabuterol, in supercritical carbon dioxide (SF-CO2) were measured by a recirculating method at temperatures of 40℃ and 60℃ and pressures between 9 MPa to 49 MPa.The compounds exhibit very limited solubilities in the range of 10^-5 to 10^-7 (mole fraction). Cimaterol has a higher solubility than that of mabuterol. The experimental data of solubility were correlated by four density-based models.The correlation accuracy highly depends on the system investigated, which is mainly determined by the density ranges and temperature.

液相色谱-串联四极杆质谱法对动物源基质中β_2-受体激动剂的检测

A method for the simultaneous determination of β2-agonists residues was developed by LC-MS/MS.The results indicated that the calibration curves showed good linear range from 0.1 g/L to 10 g/L for 11 β2-agonists.The spiked recoveries were between 79% and 110%.The method was rapid,accurate,and was suitable for the determination of β2-agonists in animal food.

超高效液相色谱-串联质谱法对饲料中15种β-肾上腺素能激动剂的测定

A UPLC-MS/MS method was established for the determination of fifteen kinds of β-agonists in feed.The analytes were separated on a column of BEH C18 100 mm×2.1 mm(i.d.) employing methanol as mobile phase A and 0.2% formic acid as mobile phase B(VA∶VB=1∶1).The analytes were determined by tandem MS under ESI+ and MRM mode.The linearity of fifteen kinds of β-agonists was range of 1-50 μg/L.The spiked recoveries of fifteen kinds of β-agonists ranged from 60% to 105%.The LOD and LOQ of the method were 0.1 mg/kg and 0.05 mg/kg,respectively.

Determination of 23 β_2-agonists and 5 β-blockers in animal muscle by high performance liquid chromatography-linear ion trap mass spectrometry

A high performance liquid chromatography-linear ion trap mass spectrometry method using isotope dilution technique has been developed for the simultaneous determination of 23 β2-agonists and 5 β-blockers in animal muscle tissues. Pork and chicken muscle samples were acid hydrolyzed and extracted with 5% trichloracetic acid in water, and then cleaned up using MCX solid phase extraction (SPE) cartridge. Methanol and 0.1% formic acid were used as mobile phases for gradient elution. A Waters AtlantisT3 column was used for separation. ESI positive ion scan mode was used with selective reaction monitoring. 9 β2-Agonists labeled by the deuterium isotope were used as internal standards for quantification. The linear ranges of 23 β2-agonists and 5 β-blockers were 5-200 μg/L, the coefficient of correlation was not less than 0.995, and the limit of detection for each compound in the muscle tissue was below 0.2 μg/kg. The recoveries of each compound in the spiked samples at three levels 5, 10, 20 μg/kg were in the range of 47.3%-123.7%, and the relative standard deviations were in the range of 3.2%-25.7%. The developed method is sensitive and specific for the determination of β2-agonists and β-blockers in pork and chicken muscle samples.

猪尿中7种β-肾上腺素能激动剂残留检测的超高效液相色谱-串联质谱法研究

A UPLC-MS/MS method was presented to analyze 7 β-agonists residues in swine urine.The experimental results indicated that the recoveries ranged from 65%-111% and the RSDs were 3.07%-19.13%.The limits of quantification(LOQ) was 0.5 μg/L,and the detection limit(LOD)was 0.2 μg/L.

β_2-adrenoceptor in obstructive airway diseases:Agonism, antagonism or both?

Obstructive airway disease is a complex disease entity including several maladies characterized by bronchoconstriction and abnormal airway inflammation. Reversing bronchoconstriction leads to symptomatic relief and improvement in quality of life, both in reversible(bronchial asthma) and partially reversible(chronic obstructive airway disease) obstructive airway diseases. β2-adrenoceptor expressed in human airway is the main β-receptor subtype, and its activation in airway smooth muscle cells leads to bronchodilatation. Drugs targeting β-adrenoceptors have been around for many years, for which agonists of the receptors are used in bronchodilation while antagonists are used in cardiovascular diseases. This review article summarizes the effect and usage of β2-agonist in obstructive airway disease, addressing the benefits and potential risks of β2-agonist. The article also looks at the safety of β-blocker usage for cardiovascular disease in patients with obstructive airway disease. There is also emerging evidence that non-selective β-blockers with inverse agonism ironically can have longterm beneficial effects in obstructive airway disease that is beyond cardiovascular protection. Further trials are urgently needed in this area as it might lead to a dramatic turnaround in clinical practice for obstructive airway diseases as has already been seen in the usage of β-blockers for heart failure.

Voltammetric Method Using Multi-Walled Carbon Nanotubes Modified Glassy Carbon Electrode for the Determination of Terbutaline Sulfate in Pork Sample

Electrochemical properties of terbutaline sulfate (TBS) at the glassy carbon electrode modified with multi-walled carbon nanotubes (MWNTs) were explored by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The response was evaluated with respect to pH, scan rate and other variables. Some electrochemical parameters, such as the charge number and proton number, were calculated. The results indicated that TBS underwent irreversible oxidation at the modified electrode, which was an adsorption-controlled process with two protons and two electrons. The reductive peak current of TBS significantly increased and the peak potential shifted negatively at the modified electrode, thus resulting in an electrode for TBS. The current was proportional to the concentration of TBS over 1.12 and 141 μM with a detection limit of 0.34 μM (at S/N = 3). The modified electrode showed good sensitivity, selectivity and stability for the determination of TBS in pork sample.

Fast Determination of Clenbuterol and Salbutamol in Feed and Meat Products Based on Miniaturized Capillary Electrophoresis with Amperometric Detection

The fast separation capability of a novel miniaturized capillary electrophoresis with an amperometric detection （μCE-AD） system was demonstrated by determining clenbuterol and salbutamol in real samples. The effects of several factors such as the acidity and concentration of the running buffer, the separation voltage, the applied potential and the injection time on CE-AD were examined and optimized. Under the optimum conditions, the two β-agonists could be baseline separated within 60 s at a separation voltage of 2 kV in a 90 mmol/L H3BO3-Na2B4O7 running buffer （pH 7.4）, which was not interfered by ascorbic acid and uric acid. Highly linear response was obtained for above compounds over three orders of magnitude with detection limits ranging from 1.20×10^-7 to 6.50×10^-8 mol/L （S/N=3）. This method was successfully used in the analysis of feed and meat products with relatively simple extraction procedures.

Distinct roles but cooperative effect of TLR3/9 agonists and PD-1 blockade in converting the immunotolerant microenvironment of irreversible electroporation-ablated tumors

Irreversible electroporation(IRE)is a new cancer ablation technology,but methods to improve IRE-induced therapeutic immunity are only beginning to be investigated.We developed a mouse model bearing large primary(300 mm^(3))and medium distant(100 mm^(3))EG7 lymphomas engineered to express ovalbumin(OVA)as a nominal tumor antigen.We established experimental protocols including IRE alone and IRE combined with Toll-like receptor(TLR)3/9 agonists(poly I:C/CpG)(IRE+pIC/CpG),PD-1 blockade(IRE+PD-1 blockade),or both(IRE+Combo)to investigate therapeutic effects on primary and distant EG7 tumors and conversion-promoting effects on the immunotolerant tumor microenvironment(TME).We demonstrated that IRE alone simulated very weak OVA-specific CD8^(+)T cell responses and did not inhibit primary tumor growth.IRE+pIC/CpG synergistically stimulated more efficient OVA-specific CD8^(+)T cell responses and primary tumor growth inhibition than IRE+PD-1 blockade.IRE+pIC/CpG played a major role in the modulation of immune cell profiles but a minor role in the downregulation of PD-L1 expression in the TME and vice versa for IRE+PD-1 blockade.IRE+Combo cooperatively induced potent OVA-specific CD8^(+)T cell immunity and rescued exhausted intratumoral CD8^(+)T cells,leading to eradication of not only primary tumors but also untreated concomitant distant tumors and lung metastases.IRE+Combo efficiently modulated immune cell profiles,as evidenced by reductions in immunotolerant type-2(M2)macrophages,myeloid-derived suppressor-cells,plasmacytoid dendritic cells,and regulatory T cells and by increases in immunogenic M1 macrophages,CD169^(+)macrophages,type-1 conventional dendritic cells,and CD8^(+)T cells,leading to conversion of immunotolerance in not only primary TMEs but also untreated distant TMEs.IRE+Combo also showed effective therapeutic effects in two breast cancer models.Therefore,our results suggest that IRE+Combo is a promising strategy to improve IRE ablation therapy in cancer.