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Mass Spectrometric Analysis
Published in Adorjan Aszalos, Modern Analysis of Antibiotics, 2020
Another general approach is the direct liquid inlet in which a fraction of the solvent enters a Cl source [113,114], The solvent acts as the reagent gas to produce CI mass spectra. Most solvents can be tolerated, including water buffered with ammonium formate or acetate [113–116]. The direct liquid inlet system is limited to solvent flow rates of less than 100 μl/min [117]; the entire eluant from a microbore liquid chromatographic column can be accommodated. A problem causing the capillary inlet tube to plug has apparently been rectified with recent modifications [118,119]. This technique has been used to obtain positive and negative ion CI mass spectra of very polar compounds [119], even though doubt has been expressed concerning its application to nonvolatile species [117]. This type of interface is commercially available.
Reactivities of Amino Acids and Proteins with Iodine
Published in Erwin Regoeczi, Iodine-Labeled Plasma Proteins, 2019
Separation of I–, iodotyrosines, and thyroid hormones can be undertaken on the cation- exchange resin, Dowex® 50W-X4.502 The adsorbed hydrolysate (from 1 mg protein for a 0. 9 x 20 cm column) is eluted by using a variable gradient multichamber apparatus. Eight different solutions (ammonium formate, NH4OH, and their mixtures) are used for elution, each containing 30% (v/v) ethanol. Indirect evidence suggests that the method is also useful for the isolation of iodohistidines. The ethanol is required for the separation of thyronines and is dispensable when they are absent from a hydrolysate.503 This procedure offers, from an analytical point of view, no advantages over the techniques already discussed, but it seems useful for preparative purposes.
Phosphatidylinositol and inositolphosphatide metabolism in hypertrophied rat heart
Published in H. Saito, Y. Yamori, M. Minami, S.H. Parvez, New Advances in SHR Research –, 2020
Hideaki Kawaguchi, Akira Kitabatake
Cellular response to norepinephrine. For determination of the cellular response of PLC activity to NE, myocytes (3×106) were prelabeled with [3H] myoinositol 50 mCi for 24 h in 10 ml phosphate buffer with 0.3% fetal calf serum in 10 cm dishes. The cells were then washed with PB three times in 50 ml Falcon centrifuge tubes and subcultured (3 × 105 cells/dish) in 1 ml of PB containing 1 mM CaCh 35-mm dishes for assays. The preliminary experiments revealed that the incorporation of [3H] myoinositol into cardiac cells from WKY reached 3.5 ± 0.6% at 16 h-incubation and plateaued for 24 to 72 h. Its maximal incorporation rates into SHRSP and WKY were 4.6 ± 1.0% / 10-cm dish and ± 1.0%/10-cm dish, respectively. In this experiments, cells were labeled with [3H] myoinositol for 24 hr at 37°C. The viability of cell after labeling was about 90%. Cells were incubated with the indicated concentrations of NE, 5 mM 2, 3-DPG (Downes et al., 1982), and 10 mM LiCl for the indicated periods in the presence of 1 mM metoprolol (Japan CIBA-GEIGY, Osaka Japan) to preclude the effect of bl-adrenergic receptor stimulation. The assay was terminated with 30 ml N HC1, and then lipids were extracted with ice-cold 3 ml chloroform/methanol (2:1, v/v). The incubation mixture was centrifuged 2,500 rpm for 5 min at 4°C, and then the aqueous phase was applied to an AG 1 × 8 column. Inositol monophosphate, IP2, IP3 and IP4 were separated by elution from AG 1 × 8 columns in formate form (100-200 mesh) by a gradient of ammonium formate (0.2-1.2 M) plus 0.1 M formic acid (Downes et al., 1986; Merritt et al., 1986). To check the migration of these fractions from AGI × 8 to each others, the aliquots (10,000 dpm each from IP3 and IP4) of samples from SHRSP heart cells treated with NE 1 mM were desalted by elution from Dowex chloride column, filtered and separated by high performance-liquid chromatography (HPLC; Whatman Partisil 10 SAX anion-exchange column with a guard column) with a gradient of ammonium formate and phosphate (Howkins, 1986). Figure 1 shows the recoveries in these fractions from AG 1 × 8 column. The recoveries of IP3 and IP4 were 70 ± 3% and 60 ± 5%, respectively. Each fraction was clearly separated. These preliminary experiments revealed that AG 1 × 8 column chromatography was enuogh to separate polyphosphoinositides instead of HPLC. This column chromatography system was used in this study.
Influence of verapamil on the pharmacokinetics of rotundic acid in rats and its potential mechanism
Published in Pharmaceutical Biology, 2021
Haihua Shang, Ze Wang, Hong Ma, Yinghui Sun, Xiaoyan Ci, Yuan Gu, Changxiao Liu, Duanyun Si
Verapamil hydrochloride (purity greater than 99.0%), β-nicotinamide adenine dinucleotide phosphate (NADPH), Lucifer yellow, and rhodamine-123 were obtained from Sigma-Aldrich (St. Louis, MO, USA). Rotundic acid (purity greater than 98.6%) was purchased from Chengdu Pufei De Biotech Co., Ltd. (Sichuan, China). Etofesalamide (Internal Standard, IS) was obtained from the National Institutes for Food and Drug Control (Beijing, China). Rat liver microsomes, rhCYP 1A2, 2C8, 2C9, 2D6 and 3A4 were provided from the Research Institute for Liver Disease (Shanghai) Co., Ltd. (Shanghai, China). Dulbecco’s Modified Eagle Medium (DMEM), penicillin (10,000 U/mL)-streptomycin (10 mg/mL), non-essential amino acids (NEAA), and foetal bovine serum (FBS) were acquired from GIBCO (Grand Island, NY, USA). CellTiter 96 Aqueous One Solution Cell Proliferation Assay (MTS) kit was provided from Promega Corp. (Madison, WI, USA). The HPLC grade acetonitrile and methanol were purchased from Thermo Fisher Scientific (China) Co., Ltd. (Shanghai, China). The analytical grade ammonium formate used in this experiment was procured from Tianjin Guangfu Fine Chemical Research Institute (Tianjin, China). Highly pure deionized water was prepared in-house using the BM-40 water purification system from Zhongsheng Maoyuan Tech. Co., Ltd. (Beijing, China). All other chemicals and reagents were of analytical grade and commercially available.
Phase I and phase II metabolism simulation of antitumor-active 2-hydroxyacridinone with electrochemistry coupled on-line with mass spectrometry
Published in Xenobiotica, 2019
Agnieszka Potęga, Dorota Garwolińska, Anna M. Nowicka, Michał Fau, Agata Kot-Wasik, Zofia Mazerska
An acridinone derivative, a 2-hydroxyacridinone (2-OH-AC) was synthesized in our laboratory according to the method described earlier (Acheson, 1973). The following chemicals were purchased from Sigma-Aldrich (St. Louis, MO): N-acetylcysteine (NAC), dipotassium phosphate (K2HPO4), disodium phosphate (Na2HPO4), formic acid (HCOOH), L-glutathione reduced (GSH), monopotassium phosphate (KH2PO4), monosodium phosphate (NaH2PO4) and semicarbazide hydrochloride. Methanol (gradient grade for liquid chromatography) and β-nicotinamide adenine dinucleotide 2′-phosphate tetrasodium salt (β-NADPH) were obtained from Merck KGaA (Darmstadt, Germany). Ammonium formate (HCOONH4) was ordered from Fisher Scientific (Loughborough, UK). Aluminum oxide (Al2O3) powder in form of 1-µm alumina suspension for polishing of electrodes was delivered by TESTING Sp z o.o. (Katowice, Poland). All other commercially available chemicals and reagents were of the highest possible grade available. Ultrapure water (0.056 μS·cm−1), used in all the experiments, was passed through a Milli-Q water purification system from Merck KGaA (Darmstadt, Germany) or water distillation system from Hydrolab Sp. z o.o. Sp.K. (Straszyn, Poland).
Effects of rosiglitazone/PHBV drug delivery system on postoperative fibrosis in rabbit glaucoma filtration surgery model
Published in Drug Delivery, 2019
Feng Zhang, Ke Liu, Zheng Pan, Mengdan Cao, Dengming Zhou, Hairong Liu, Yuting Huang, Xuanchu Duan
The assays include chloroform (TCM), dimethylformamide (DMF), dimethyl sulfoxide (DMSO) and PHBV, which were purchased from Sigma (USA). Rosiglitazone was obtained from BioVision (USA). Ammonium formate came from Fisher scientific (USA). Acetonitrile was obtained from Merck Millipore (Germany). Filed emission scanning electron microscope SU8010 was obtained from Hitachi (Tokyo, Japan). LC-20A high-performance liquid chromatography (HPLC) were obtained from Shimadzu equipped with an autosampler (Model SIL-20A), a column temperature controller compartment (CTO-10AS) and ultraviolet detector (SPD-M20A). Diamonsil C18 column (5 μ 250 × 4.6 mm) were purchased from Dikma Technologies Inc., China. PH meter came from Denver Instrument, USA. TonoVet were obtain from Icare, Finland. In the vivo experiments, the assays include pentobarbital sodium (30 mg/kg) (Solarbio, Beijing, China), Benoxil (Santen, Japan), Tobramycin Dexamethasone Eye Ointment (Alcon, USA), 0.5% Levofloxacin Eye Drops (Santen, Japan), 4% Paraformaldehyde (Solarbio, Beijing, China), suture line (10-0 nylon; Alcon; USA), 8-0 Vicryl suture (Ethicon; USA), Normal Saline (Second Xiangya Hospital, Changsha, China), Mitomycin C (Sigma, USA), anti-Collagen I antibody (Abcam, UK), anti-α-SMA antibody (Abcam, UK), and anti-connective tissue growth factor (CTGF) antibody (Abcam, UK).