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Sympathetic Regulation of Aquaporin Water Channels in Rat Kidney
Lee, Jong-Un,Yoo, Kwang-Jay,Oh, Yoon-Wha,Lim, Dong-Yoon The Korean Society of Pharmacology 2003 The Korean Journal of Physiology & Pharmacology Vol.7 No.3
Whether there exists a sympathetic neural regulation on the aquaporin (AQP) channels in the kidney was examined. Male Sprague-Dawley rats were used. They were renal nerve denervated by stripping the nervous and connective tissues passing along the renal artery and vein, and painting these vessels with 10% phenol solution through a midline abdominal incision. Three days later, the expression of AQP1-4 proteins in the denervated kidneys was determined. The content of norepinephrine was found significantly decreased following the denervation. Accordingly, the expression of AQP2 proteins was markedly decreased. The expression of AQP3 and AQP4 was also slightly but significantly decreased, while that of AQP1 was not. Neither the basal nor the AVP-stimulated accumulation of cAMP was significantly affected in the denervated kidney. It is suggested that the sympathetic nervous system has a tonic stimulatory effect on AQP channels in the kidney.
Grain-Refined AZ92 Alloy with Superior Strength and Ductility
Lee, Jong Un,Kim, Sang-Hoon,Jo, Wan-Kuen,Hong, Won-Hwa,Kim, Woong,Bae, Jun Ho,Park, Sung Hyuk Springer-Verlag 2018 METALS AND MATERIALS International Vol.24 No.4
<P>Grain-refined AZ92 (GR-AZ92) alloy with superior tensile properties is developed by adding 1 wt% Zn and a very small amount of SiC (0.17 wt%) to commercial AZ91 alloy for enhancing the solid-solution strengthening effect and refining the crystal grains, respectively. The homogenized GR-AZ92 alloy with an average grain size of 91 mu m exhibits a tensile yield strength (TYS) of 125 MPa, ultimate tensile strength (UTS) of 281 MPa, and elongation of 12.1%, which are significantly higher than those of AZ91 alloy with a grain size of 420 mu m (TYS of 94 MPa, UTS of 192 MPa, and elongation of 7.0%). The peak-aging time of GR-AZ92 alloy (8 h) is significantly shorter than that of AZ91 alloy (32 h) owing to a larger amount of grain boundaries in the former, which serve as nucleation sites of Mg17Al12 precipitates. A short-aging treatment for less than 1 h of the GR-AZ92 alloy causes an effective improvement in its strength without a significant reduction in its ductility. The 30-min-aged GR-AZ92 alloy has an excellent combination of strength and ductility, with a TYS of 142 MPa, UTS of 304 MPa, and elongation of 8.0%.</P>
Endocrine disrupting potential of PAHs and their alkylated analogues associated with oil spills
Lee, Sangwoo,Hong, Seongjin,Liu, Xiaoshan,Kim, Cheolmin,Jung, Dawoon,Yim, Un Hyuk,Shim, Won Joon,Khim, Jong Seong,Giesy, John P.,Choi, Kyungho The Royal Society of Chemistry 2017 Environmental science Vol.19 No.9
<▼1><P>Polycyclic aromatic hydrocarbons (PAHs) and alkylated PAHs are known to be major toxic contaminants in spills of petroleum hydrocarbons (oil).</P></▼1><▼2><P>Polycyclic aromatic hydrocarbons (PAHs) and alkylated PAHs are known to be major toxic contaminants in spills of petroleum hydrocarbons (oil). Spilled oil undergoes weathering and over time, PAHs go through a series of compositional changes. PAHs can disrupt endocrine functions, and the type of functions affected and associated potencies vary with the type and alkylation status of PAH. In this study, the potential of five major PAHs of crude oil, <I>i.e.</I>, naphthalene, fluorene, dibenzothiophene, phenanthrene, and chrysene, and their alkylated analogues (<I>n</I> = 25), to disrupt endocrine functions was evaluated by use of MVLN-<I>luc</I> and H295R cell lines. In the MVLN-<I>luc</I> bioassay, seven estrogen receptor (ER) agonists were detected among 30 tested PAHs. The greatest ER-mediated potency was observed for 1-methylchrysene (101.4%), followed by phenanthrene and its alkylated analogues (range of %-E2max from 1.6% to 47.3%). In the H295R bioassay, significantly greater syntheses of steroid hormones were observed for 20 PAHs. For major PAHs and their alkylated analogues, disruption of steroidogenesis appeared to be more significant than ER-mediated effects. The number and locations of alkyl-moieties alone could not explain differences in the types or the potencies of toxicities. This observation shows that disruption of endocrine functions by some constituents of oil spills could be underestimated if only parent compounds are considered in assessments of hazard and risk.</P></▼2>