Publications by authors named "Liu Hua Fen"

Article Synopsis
  • Fibroblast-derived exosomes are shown to play a role in regulating heart cell electrical activity, particularly through the intermediate-conductance calcium-activated potassium channel (KCa3.1), which is involved in atrial electrical remodeling.
  • The study involved isolating heart cells from rats and using electrical stimulation to create a model of atrial fibrillation, with experiments designed to see how exosomes from fibroblasts influenced KCa3.1 and related mechanisms.
  • Findings indicated that increased exosome secretion during rapid heart pacing enhanced KCa3.1 expression and altered heart cell action potentials, while blocking KCa3.1 reduced action potential duration and potentially the risk of atrial fibrillation.
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Background: In response to a need for accurate and reliable methods for food allergen regulatory compliance, a method for the detection and quantitation of whole egg, whole milk, peanut, and hazelnut in eight food matrices was developed and evaluated in a single-laboratory validation. The matrices include cookies, cookie dough, bread, breakfast cereal, salad dressing, ice cream, and red wine.

Objective: The method was compared with Standard Method Performance Requirements (SMPR) 2016.

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There is currently no cure for food allergies, and sufferers can only rely on the correct labeling of foods to avoid allergens. Hence, it is important that analytical methods are sensitive and accurate enough to screen for the presence of multiple allergens in food products. In this study, we developed an LC-tandem MS method that is able to simultaneously screen or quantify the signature tryptic peptides of multiple allergen commodities.

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Background: Since the mid-2000s synthetic cannabinoids have been abused as recreational drugs, prompting scheduling of these substances in many countries. To circumvent legislation, manufacturers constantly market new compounds; [1-(5-fluoropentyl)indol-3-yl]-(2,2,3,3-tetramethylcyclopropyl)methanone (XLR-11), the fluorinated UR-144 analog, is one of the most recent and widely abused drugs, and its use is now linked with acute kidney injury. Our goal was to investigate XLR-11 metabolism for identification of major urinary targets in analytical methods and to clarify the origin of metabolites when one or more parent synthetic cannabinoids can be the source.

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Since the federal authorities scheduled the first synthetic cannabinoids, JWH-018 and JWH-073, new synthetic cannabinoids were robustly marketed. N-(1-Adamantyl)-1-pentylindazole-3-carboxamide (AKB-48), also known as APINACA, was recently observed in Japanese herbal smoking blends. The National Forensic Laboratory Information System registered 443 reports of AKB-48 cases in the USA from March 2010 to January 2013.

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Objective: To observe the effect on the inhibition of coronary atherosclerosis hardening of the paraoxonase gene (PON-1) which transfected to the rabbit epicardial adipose tissue.

Methods: Rabbit coronary atherosclerosis model was established by high-fat feeding, liposome-encapsulated recombinant plasmid pEGFP-PON-1 50 μ L was injected to the rabbit pericardial cavity, and was harvested 4 weeks after transfection.

Results: The epicardial fat transfected PON-1 gene had effect on the high lipid level.

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Currently, ∆9-tetrahydrocannabinol (THC) is the analyte quantified for oral fluid cannabinoid monitoring. The potential for false-positive oral fluid cannabinoid results from passive exposure to THC-laden cannabis smoke raises concerns for this promising new monitoring technology. Oral fluid 11-nor-9-carboxy-∆9-tetrahydrocannabinol (THCCOOH) is proposed as a marker of cannabis intake since it is not present in cannabis smoke and was not measureable in oral fluid collected from subjects passively exposed to cannabis.

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Introduction: Synthetic cannabinoids are an emerging illicit drug class. The variety of available substances is large and ever-changing, making it difficult for laboratories to remain current. We present a qualitative LC-MS/MS method identifying urinary metabolites of JWH-018, JWH-073, JWH-081, JWH-122, JWH-200, JWH-210, JWH-250, RCS-4, and AM2201 and the parent compounds JWH-018, JWH-073, JWH-081, JWH-122, JWH-210, JWH-250, RCS-4, AM2201, and MAM2201.

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Atrial fibrillation (AF) is the most common sustained dysrhythmia in clinical practice. The bulk of evidence suggests that inflammatory processes, oxidative stress and matrix metalloproteinase are associated with development of AF. However, these agents may be involved in high mobility group box 1 protein (HMGB1).

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Aims: Accurate serum aldosterone determination is critical to the screening and diagnosis of primary aldosteronism, the localisation of aldosterone producing tumours, and the investigation of other disorders of the renin-angiotensin system. Mass spectrometry offers a means to overcome problems with method-dependent bias between competitive immunoassays for aldosterone. The authors have developed a simple, sensitive and precise liquid-liquid extraction aldosterone method for the ABSCIEX API-5000 liquid chromatography and tandem mass spectrometry (LC-MS/MS) system.

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Drugs can be metabolically activated to soft and hard electrophiles, which are readily trapped by glutathione (GSH) and cyanide (CN), respectively. These adducts are often detected and structurally characterized using separate tandem mass spectrometry methods. We describe a new method for simultaneous screening of GSH and CN adducts using precursor ion (PI) and neutral loss (NL) scans-dependent product ion spectral acquisition and data mining tools on an triple quadrupole linear ion trap mass spectrometry.

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A simple, robust, and sensitive liquid chromatography-tandem mass spectrometric (LC-MS/MS) method was developed for the measurement of endogenous adenine in mouse, rat, cynomolgus monkey, and human plasma. A "surrogate analyte" strategy was adopted by employing [(13)C(U)]-adenine as the surrogate analyte. The plasma samples were processed by protein precipitation, and the extracted supernatant samples were subjected directly to LC-MS/MS analysis.

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The involvement of cytochrome P450 2B6 (CYP2B6) to the in vitro and in vivo metabolism of bupropion has been well studied. In these investigations we performed a detailed in vitro phenotyping study to characterize isoforms other than CYP2B6. A total of nine metabolites were identified (M1-M9) in the incubations with cDNA-expressed P450s (rhCYP) and human liver microsomes (HLM).

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Objective: This prospective and randomize-controlled trial was designed to investigate the effects of antiarrhythmic drug use (AADs) on atrial fibrillation (AF) recurrence in atrial fibrillation patients post circumferential pulmonary vein ablation (CAPV).

Methods: Seventy-four consecutive AF patients underwent CAPV (41 paroxysmal and 33 drug refractory AF) were randomly assigned to receive placebo (Group A) or AADs (Group B) for 3 months. Monthly standard electrocardiograms (ECG) and Holter monitoring were performed to assess AF recurrences during 17 - 28 months follow-up.

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