Publications by authors named "Jang H Youn"

Background: Citrus peels are rich in flavonoids with potential sedative-hypnotic effects; however, these effects have not yet been fully explored. We previously demonstrated that, in mice, standardized lime peel supplement (SLPS) induced non-rapid eye movement sleep and shortened sleep latency through GABA receptors activation.

Purpose And Study Design: This study aimed to evaluate the effects of SLPS in adults experiencing sleep disturbances.

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Maintaining extracellular potassium (K) within narrow limits, critical for membrane potential and excitability, is accomplished through the internal redistribution of K between extracellular fluid (ECF) and intracellular fluid (ICF) in concert with the regulation of renal K output to balance K intake. Here we present evidence from high-precision analyses of stable K isotopes in rats maintained on a control diet that the tissues and organs involved in the internal redistribution of K differ in their speed of K exchange with ECF and can be grouped into those that exchange K with ECF either rapidly or more slowly ("fast" and "slow" pools). After 10 days of K restriction, a compartmental analysis indicates that the sizes of the ICF K pools decreased but that this decrease in ICF K pools was not homogeneous, rather occurring only in the slow pool (15% decrease, < 0.

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Polyphenols have been well-established to exert sedative-hypnotic effects in psychopharmacology. Lime (Citrus aurantifolia) peel is rich in biologically active polyphenols; however, the effects of lime peel extract on sleep have not yet been demonstrated. A comparison was conducted in mice, between the sleep-promoting effects of a standardized lime peel supplement (SLPS) and a well-known hypnotic drug, zolpidem, and its hypnotic mechanism was investigated using in vivo and in vitro assays.

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Hypertriglyceridemia is a risk factor for type 2 diabetes and cardiovascular disease (CVD). Plasma triglycerides (TGs) are a key factor for assessing the risk of diabetes or CVD. However, previous lipidomics studies have demonstrated that not all TG molecules behave the same way.

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Soluble epoxide hydrolase (sEH) is an important enzyme for metabolic and cardiovascular health. sEH converts FFA epoxides (EpFAs), many of which are regulators of various cellular processes, to biologically less active diols. In human studies, diol (sEH product) to EpFA (sEH substrate) ratios in plasma or serum have been used as indices of sEH activity.

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Membrane-based organic solvent separations are rapidly emerging as a promising class of technologies for enhancing the energy efficiency of existing separation and purification systems. Polymeric membranes have shown promise in the fractionation or splitting of complex mixtures of organic molecules such as crude oil. Determining the separation performance of a polymer membrane when challenged with a complex mixture has thus far occurred in an ad hoc manner, and methods to predict the performance based on mixture composition and polymer chemistry are unavailable.

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Oxylipins, oxidation products of unsaturated free fatty acids (FFAs), are involved in various cellular signaling systems. Among these oxylipins, FFA epoxides are associated with beneficial effects in metabolic and cardiovascular health. FFA epoxides are metabolized to diols, which are usually biologically less active, by soluble epoxide hydrolase (sEH).

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As the most abundant cation in archaeal, bacterial, and eukaryotic cells, potassium (K) is an essential element for life. While much is known about the machinery of transcellular and paracellular K transport-channels, pumps, co-transporters, and tight-junction proteins-many quantitative aspects of K homeostasis in biological systems remain poorly constrained. Here we present measurements of the stable isotope ratios of potassium (K/K) in three biological systems (algae, fish, and mammals).

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Extracellular potassium (K) homeostasis is achieved by a concerted effort of multiple organs and tissues. A limitation in studies of K homeostasis is inadequate techniques to quantify K fluxes into and out of organs and tissues in vivo. The goal of the present study was to test the feasibility of a novel approach to estimate K distribution and fluxes in vivo using stable K isotopes.

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Soluble epoxide hydrolase (sEH) converts several FFA epoxides to corresponding diols. As many as 15 FFA epoxide-diol ratios are measured to infer sEH activity from their ratios. Using previous data, we assessed if individual epoxide-diol ratios all behave similarly to reflect changes in sEH activity, and whether analyzing these ratios together increases the power to detect changes in in-vivo sEH activity.

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Scope: High sodium and low potassium (HNaLK) intake increases the risk of cardiovascular disease (CVD) and metabolic syndrome. The authors investigate if the dietary minerals interact with the gut microbiota to alter circulating lipid profiles, implicated in CVD and metabolic syndrome.

Methods And Results: Plasma samples from Wistar rats fed a control or HNaLK diet with or without antibiotic treatment (n = 7 each, a total of 28) are subjected to lipidomics analysis.

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Carbon molecular sieve (CMS) membranes are candidates for the separation of organic molecules due to their stability, ability to be scaled at practical form factors, and the avoidance of expensive supports or complex multi-step fabrication processes. A critical challenge is the creation of "mid-range" (e.g.

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Scope: High-sodium and low-potassium (HNaLK) content in Western diets increases the risk of hypertension and cardiovascular disease (CVD). It is investigated if the dietary minerals interact with gut bacteria to modulate circulating levels of biogenic amines, which are implicated in various pathologies, including hypertension and CVD.

Methods And Results: Using a metabolomic approach to target biogenic amines, the effects of gut bacteria depletion and HNaLK intake on circulating levels of biogenic amines in rats are examined.

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Epoxides of free fatty acids (FFAs), especially epoxyeicosatrienoic acids (EETs), are lipid mediators with beneficial effects in metabolic and cardiovascular (CV) health. FFA epoxides are quickly metabolized to biologically less active diols by soluble epoxide hydrolase (sEH). Inhibition of sEH, which increases EET levels, improves glucose homeostasis and CV health and is proposed as an effective strategy for the treatment of diabetes and CV diseases.

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Potassium homeostasis has a very high priority because of its importance for membrane potential. Although extracellular K is only 2% of total body K, our physiology was evolutionarily tuned for a high-K, low-Na diet. We review how multiple systems interface to accomplish fine K balance and the consequences for health and disease.

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Previous rodent studies showed that when injected into the brain, free fatty acids (FFAs) reduced food intake in an oleate-specific manner. The present study was performed to test whether food intake is regulated by circulating FFAs in an oleate-specific manner. Male Wistar rats received an intravenous infusion of olive, safflower, or coconut oil (100mg/h), together with heparin, to raise circulating oleate, linoleate, or palmitate, respectively, and their effects on overnight food intake were evaluated.

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Inflammation is implicated in metabolic abnormalities in obesity and type 2 diabetes. Because θ-defensins have anti-inflammatory activities, we tested whether RTD-1, a θ-defensin, improves metabolic conditions in diet-induced obesity (DIO). DIO was induced by high-fat feeding in obese-prone CD rats from 4 wk of age.

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Fat sensing and metabolic syndrome.

Rev Endocr Metab Disord

December 2014

Overconsumption of dietary fat contributes to the development of obesity and metabolic syndrome. Recent evidence suggests that high dietary fat may promote these metabolic states not only by providing calories but also by inducing impaired control of energy balance. In normal metabolic states, fat interacts with various organs or receptors to generate signals for the regulation of energy balance.

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The short half-life of current positron emission tomography (PET) cardiac tracers limits their widespread clinical use. We previously developed a (18)F-labeled phosphonium cation, [(18)F]FPTP, that demonstrated sharply defined myocardial defects in a corresponding infarcted myocardium. The aim of this study was to compare the image properties of PET scans obtained using [(18)F]FPTP with those obtained using [(13)N]NH3 in rat myocardial infarction models.

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[11C]Acetate, a radiotracer for PET imaging, is a promising radiopharmaceutical for overcoming the limitation of 2-deoxy-2-[18F]fluoro-D-glucose in a number of cancers. Here, the optimized automatic synthesis of [11C]acetate using an in-house-developed module under different conditions has been reported for routine production. [11C]CO2 was produced in a 16.

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Dietary potassium loading results in rapid kaliuresis, natriuresis, and diuresis associated with reduced phosphorylation (p) of the distal tubule Na(+)-Cl(-) cotransporter (NCC). Decreased NCC-p inhibits NCC-mediated Na(+) reabsorption and shifts Na(+) downstream for reabsorption by epithelial Na(+) channels (ENaC), which can drive K(+) secretion. Whether the signal is initiated by ingesting potassium or a rise in plasma K(+) concentration ([K(+)]) is not understood.

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We previously showed that a fall in the plasma free fatty acid (FFA) level increases plasma corticosterone levels in rats by activating the hypothalamic-pituitary-adrenal axis. In the present study, we tested whether this regulation is mediated by specific or all species of FFAs. Nicotinic acid (NA) (30 μmol/h) was infused in rats to decrease plasma FFAs and increase plasma ACTH and corticosterone.

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