Puerarin activates endothelial nitric oxide synthase through estrogen receptor-dependent PI3-kinase and calcium-dependent AMP-activated protein kinase

The cardioprotective properties of puerarin, a natural product, have been attributed to the endothelial nitric oxide synthase (eNOS)-mediated production of nitric oxide (NO) in EA.hy926 endothelial cells. However, the mechanism by which puerarin activates eNOS remains unclear. In this study, we sought to identify the intracellular pathways underlying eNOS activation by puerarin. Puerarin induced the activating phosphorylation of eNOS on Ser1177 and the production of NO in EA.hy926 cells. Puerarin-induced eNOS phosphorylation required estrogen receptor (ER)-mediated phosphatidylinositol 3-kinase (PI3K)/Akt signaling and was reversed by AMP-activated protein kinase (AMPK) and calcium/calmodulin-dependent kinase II (CaMKII) inhibition. Importantly, puerarin inhibited the adhesion of tumor necrosis factor (TNF)-α-stimulated monocytes to endothelial cells and suppressed the TNF-α induced expression of intercellular cell adhesion molecule-1. Puerarin also inhibited the TNF-α-induced nuclear factor-κB activation, which was attenuated by pretreatment with N^G-nitro-l-arginine methyl ester, a NOS inhibitor. These results indicate that puerarin stimulates eNOS phosphorylation and NO production via activation of an estrogen receptor-mediated PI3K/Akt- and CaMKII/AMPK-dependent pathway. Puerarin may be useful for the treatment or prevention of endothelial dysfunction associated with diabetes and cardiovascular disease.     

Tris(2-butoxyethyl)phosphate and triethyl phosphate alter embryonic development,hepatic mRNA expression,thyroid hormone levels,and circulating bile acid concentrations in chicken embryos

The organophosphate flame retardants tris(2-butoxyethyl) phosphate (TBOEP) and triethyl phosphate (TEP) are used in a wide range of applications to suppress or delay the ignition and spread of fire. Both compounds have been detected in the environment and TBOEP was recently measured in free-living avian species. In this study, TBOEP and TEP were injected into the air cell of chicken embryos at concentrations ranging from 0 to 45,400 ng/g and 0 to 241,500 ng/g egg, respectively. Pipping success, development, hepatic mRNA expression of 9 target genes, thyroid hormone levels, and circulating bile acid concentrations were determined. Exposure to the highest doses of TBOEP and TEP resulted in negligible detection of the parent compounds in embryonic contents at pipping indicating their complete metabolic degradation. TBOEP exposure had limited effects on chicken embryos, with the exception of hepatic CYP3A37 mRNA induction. TEP exposure decreased pipping success to 68%, altered growth, increased liver somatic index (LSI) and plasma bile acids, and modulated genes associated with xenobiotic and lipid metabolism and the thyroid hormone pathway. Plasma thyroxine levels were decreased at all TEP doses, including an environmentally-relevant concentration (8 ng/g), and gallbladder hypotrophy was evident at ≥ 43,200 ng/g. Tarsus length and circulating thyroxine concentration emerged as potential phenotypic anchors for the modulation of transthyretin mRNA. The increase in plasma bile acids and LSI, gallbladder hypotrophy, and discoloration of liver tissue represented potential phenotypic outcomes associated with modulation of hepatic genes involved with xenobiotic and lipid metabolism.     

Cyslabdan, a new potentiator of imipenem activity against methicillin-resistant Staphylococcus aureus, produced by Streptomyces sp. K04-0144. I. Taxonomy, fermentation, isolation and structural elucidation

Cyslabdan, a new potentiator of imipenem activity against methicillin-resistant Staphylococcus aureus, was isolated from the culture broth of Streptomyces sp. K04-0144 by Diaion HP-20 and ODS column chromatographies and preparative HPLC. The structure of cyslabdan was elucidated by spectroscopic analyses including NMR. The compound has a labdane-type diterpene skeleton connecting with an N-acetylcysteine via thioether linkage.     

Pharmacokinetics and pharmacodynamics of intravenous trasemide in mutant Nagase analbuminemic rats

The importance of plasma protein binding of intravenous furosemide in circulating blood for its urinary excretion and hence its diuretic effects in mutant Nagase analbuminemic rats (NARs, an animal model for human familial analbuminemia) was reported. Based on the furosemide report, the diuretic effects of another loop diuretic, torasemide, could be expected in NARs if plasma protein binding of torasemide is considerable in the rats. This was proven by this study. After intravenous administration of torasemide, 10 mg/kg, to NARs, the plasma protein binding of torasemide was 23.3% in the rats due to binding to alpha- and beta-globulins (this value, 23.3%, was greater than only 12% for furosemide), and hence the percentages of intravenous dose of torasemide excreted in 8-h urine as unchanged drug was 14.9% in the rat (this value was considerably greater than only 7% for furosemide). After intravenous administration of torasemide to NARs, the AUC (301 versus 2680 microg/min/ml) was significantly smaller [due to significantly faster both Cl(r) (4.81 versus 0.386 ml/min/kg) and Cl(nr) (28.3 versus 3.33 ml/min/kg)], terminal half-life (18.3 versus 73.5 min) and mean residence time (6.97 versus 61.8 min) were significantly shorter (due to faster Cl, 33.2 versus 3.74 ml/min/kg), and amount of 8-h urinary excretion of unchanged torasemide (446 versus 323 microg, due to increase in intrinsic renal excretion) was significantly greater than those in control rats. The 8-h urine output and 8-h urinary excretions of sodium and chloride were comparable between two groups of rats although the 8-h urinary excretion of torasemide was significantly greater in NARs. This could be explained by the following. The amount of urinary excretion of torasemide was significantly greater in NARs than that in control rats only between 0 and 30 min urine collection. In both groups of rats, the urinary excretion rate of torasemide during 0-30 min reached an upper plateau with respect to urine flow rate as well urinary excretion rates of sodium and chloride. Therefore, the diuretic effects (8-h urine output and 8-h urinary excretions of sodium and chloride) were not significantly different between the two groups of rats.     

Potentiation of cadmium-induced cytotoxicity by sulfur amino acid deprivation through activation of extracellular signal-regulated kinase1/2 (ERK1/2) in conjunction with p38 kinase or c-jun N-terminal kinase (JNK). Complete inhibition of the potentiated toxicity by U0126 an ERK1/2 and p38 kinase inhibitor.

The mechanisms of cadmium-induced toxicity may include oxidative stress, altered redox homeostasis, and injuries to organelles. The current study was designed to study the effect of decreased cellular glutathione (GSH) content by sulfur amino acid deprivation on cadmium toxicity and to identify the signaling pathways responsible for the cytotoxicity. GSH content was increased by cadmium in H4IIE cells prior to cell death, which was prevented by excess GSH or cysteine. Cell viability, however, was not improved by GSH or cysteine complexation of cadmium. Cadmium-induced cytotoxicity was 40-fold potentiated in cells with decreased GSH by sulfur amino acid deprivation. Cadmium in combination with decreased GSH markedly increased apoptotic cell death. Mitogen-activated protein kinases including extracellular signal-regulated kinase 1/2, p38 kinase and c-Jun N-terminal kinase (JNK) were all activated 1-12 hr after sulfur amino acid deprivation. U0126 (1,4-diamino-2,3-dicyano-1,4-bis[2-aminophenylthio]butadiene), which inhibited activation of extracellular signal-regulated kinase1/2 and p38 kinase in cells under sulfur amino acid deprivation, completely prevented potentiation in Cd-induced cytotoxicity and apoptosis. Potentiation of cadmium toxicity by sulfur amino acid deprivation was prevented in part by either PD98059 or SB203580, or in cells stably expressing dominant negative mutant of JNK1, and to greater extents by PD98059 in combination with either SB203580 or JNK1(-) transfection. These results demonstrated that decreased cellular GSH content potentiated cytotoxicity induced by cadmium at the level of human exposure, and that the potentiation of cytotoxicity resulted from activation of extracellular signal-regulated kinase1/2 in conjunction with p38 kinase or JNK.     

A new acylglycosyl sterol from quisqualis fructus

A new acylglycosyl sterol (4) was isolated from the MeOH extract of Quisqualis Fructus together with four known compounds. On the basis of spectroscopic data, their structures were elucidated as clerosterol (1), betulinic acid (2), methylursolate (3), 3-O-[6'-O-(8Z-octadecenoyl)-beta-D-glucopyranosyl]-clerosterol (4) and alpha-xylofuranosyluracil (5).     

South Korean alcohol free associations: negative expectancy not predicting drinks per occasion

Introduction and Aims. Cultural and biological particulars existing in East Asian countries are likely to mediate differences in the alcohol consumption experience. Despite this no research to date has directly explored the alcohol free association or expectancy of any East Asian nations. The current research aims to provide a set of South Korean alcohol expectancies. Design and Methods. Two hundred and thirty‐seven South Koreans participated in an alcohol free association test and completed a demographic survey. Results. The results both confirmed and contradicted areas of past alcohol expectancy research. There appears to be differences in associates with high probability of recall and alcohol expectancy, where negative, negative sedating and sedating expectancy categories were not found to be predictors of South Korean drinker level. Discussion and Conclusion. The results suggest that South Koreans have a more even level of negative expectancy across all drinker categories, possibly due to a combination of linguistic, cultural and biological difference found among this population. The results provide a list of South Korean alcohol free association norms for future alcohol research in the region, with the results also underlining the need for alcohol free association tests among East Asian nations.[Mahoney BJ, Graham D, Cottrell D, Kim K‐Y. South Korean alcohol free associations: Negative expectancy not predicting drinks per occasion. Drug Alcohol Rev 2012;31:469–476]     

Enhanced protection of Ins-1 β cells from apoptosis under hypoxia by delivery of DNA encoding secretion signal peptide-linked exendin-4

In this study, we developed an expression system of exendin-4, a glucagon-like peptide (GLP-1) analog, using a secretion signal peptide (SP) to facilitate exendin-4 secretion. For delivery of the exendin-4 expression system, high-molecular-weight polyethylenimine (25 kDa, PEI25k), low-molecular-weight polyethylenimine (2 kDa, PEI2k), and polyamidoamine (PAMAM) dendrimers were evaluated as gene carriers to Ins-1 β cells. As a result, PEI25k showed the highest transfection efficiency. For the construction of the exendin-4 expression vector, DNA coding the SP sequence was inserted upstream of the exendin-4 cDNA, resulting in the construction of pβ-SP-Ex-4. Transfection assay showed that the secretion level of exendin-4 increased in the pβ-SP-Ex-4 transfected cells, compared with the pβ-Ex-4 transfected cells. To identify the β-cell protection effect of pβ-SP-Ex-4 delivery, the Ins-1 β cells were transfected with pβ-SP-Ex-4 or pβ-Ex-4 and incubated under normoxia or hypoxia. An MTT assay showed that the pβ-SP-Ex-4 transfected cells had higher β-cell viability than the pβ-Ex-4 transfected cells under hypoxia. In addition, the pβ-SP-Ex-4 transfected cells exhibited lower caspase-3 activity than the pβ-Ex-4 transfected cells. Therefore, PEI25k/pβ-SP-Ex-4 complex may be useful to protect isolated β cells from apoptosis during transplantation.