A new luciferase reporter gene assay for the detection of androgenic and antiandrogenic effects based on a human prostate specific antigen promoter and PC3/AR human prostate cancer cells.

We developed a new mammalian cell-based luciferase reporter gene assay for androgenic and antiandrogenic activities of chemicals and environmental samples. Environmental samples usually have a complex matrix that may contain the constituents acting as androgen receptor (AR) agonists, AR antagonists or aryl hydrocarbon receptor (AhR) agonists. AhR agonists are known to elicit the antiandrogenic effect through cross-talk between AR and AhR signal transduction pathways. In this study, PC3/AR human prostate carcinoma cells were transiently transfected with a prostate-specific antigen (PSA) promoter-driven luciferase expression plasmid. The cells were treated with a test compound or an environmental sample for 24 h at 37 degrees C and then measured for luciferase activity. The luciferase activity was induced by dihydrotestosterone (DHT) in a concentration-dependent manner in a concentration range from 10 fM to 1 nM. R1881, a synthetic androgen receptor agonist, induced luciferase activity and its inductive effects was additive to that of DHT. The luciferase activity was not induced by cortisol, a glucocorticoid, progesterone, a progestin, and 17beta-estradiol, an estrogen in a concentration range of up to 1 microM. DHT-induced luciferase activity was reduced by bicalutamide and cyproterone acetate, AR antagonists, and also by benzo[a]pyrene, an aryl hydrocarbon receptor agonist, through AhR-mediated pathways. All of these findings indicate that the present assay system correctly responds to AR agonists, AR antagonists and AhR agonist and, therefore, it is a powerful tool for the sensitive and selective screening of chemicals and environmental samples for their androgenic and antiandrogenic activities. We developed the first assay system, in which the expression of luciferase was driven by the promoter of a prostate-specific antigen gene, a typical human androgen-regulated gene.     

The effect of ionising radiation on poly(methyl methacrylate) used in intraocular lenses

Gamma radiation is increasingly being used to sterilise intraocular lenses (IOLs) made from poly(methyl methacrylate) (PMMA). In this study, samples of PMMA used in the fabrication of IOLs were exposed to irradiation doses typically used for their sterilisation. The effect of this treatment on the polymer was analysed by size-exclusion chromatography (SEC), UV-visible and infrared spectroscopy and scanning electron microscopy (SEM). The PMMA was found to have undergone chain scission, decarboxylation and colour change following the irradiation.     

High-performance liquid chromatography of coenzyme Q-related compounds and its application to biological materials

A convenient and precise method for the separation and determination of coenzyme Q (CoQ)-related compounds (CoQ homologues, plastoquinone-9, ubichromenol-9, etc.) was developed using high-performance liquid chromatography (HPLC). All compounds tested were separated using a reverse-phase column with a suitable mobile phase and detected at a wavelength of 275 nm. CoQ extracts in plasma and erythrocytes were purified by thin-layer chromatography prior to HPLC analysis, but such purification was not necessary when determining CoQ in urine and tissues. Hydroquinone forms of CoQ existing in animal tissues were oxidized to the corresponding quinone forms with potassium hexacyanoferrate(III). This HPLC method was applied satisfactorily to the determination of the contents of CoQ homologues in human and animal samples. CoQ10 was the only homologue detected in human samples, and CoQ8, CoQ9 and CoQ10 were native homologues of CoQ in rat tissues. Ubichromenol-9 and plastoquinone-9 were not detected in these samples.     

Hair analysis of nicotine and cotinine for evaluating tobacco smoke exposure by liquid chromatography-mass spectrometry

A simple liquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS) method for the determination of nicotine and cotinine in human hair was established. In the procedure, a hair sample (10 mg) was washed with dichloromethane and digested in 2.5 M sodium hydroxide. The digest was extracted with dichloromethane and then 25 mM hydrochloric acid in methanol was added to the extract, to prevent loss of analytes. The solution was evaporated and redissolved in the mobile phase, methanol/10 mM ammonium acetate (30/70, v/v). A 20 microL aliquot of redissolved solution was subjected to analysis. Nicotine and cotinine in human hair were quantified by using deuterated analytes as internal standards. The quantification limits were 8 microg/L for nicotine and 0.9 microg/L for cotinine. The proposed method was applied to measure the concentrations of nicotine and cotinine in hair of smokers and non-smokers to evaluate their self-reported smoking and exposure to environmental tobacco smoke. In both cases, the method provided good selectivity, accuracy and precision.     

New catalytic cycle for couplings of aldehydes with organochromium reagents

[reaction: see text] A new catalytic cycle has been developed to effect all three subgroups of Cr-mediated couplings, i.e., (1) Ni/Cr-mediated alkenylation, alkynylation, and arylation, (2) Co/Cr-mediated 2-haloallylation, alkylation, and propargylation, and (3) Cr-mediated allylation. In the presence of chiral sulfonamide ligands, good asymmetric inductions can be achieved for some of the Ni/Cr-mediated alkenylation, Co/Cr-mediated 2-haloallylation and propargylation, and Cr-mediated allylation.     

Hydrogen Effect on Coke Removal and Catalytic Performance in Pre-Carburization and Methane Dehydro-Aromatization Reaction on Mo/HZSM-5

1. Introduction As an effective utilization of methane, the methane dehydro-aromatization was focused in the last decade [1-28]. Over the Mo/HZSM-5 bi- functional catalyst at high reaction temperature, methane can be converted into light aromatics (ben- zene and naphthalene) and hydrogen. Mo active species can activate the C—H bond of methane; and HZSM-5 supplies the acid sites for the oligomeriza- tion and cyclization of hydrocarbons to form aromat- ics, and suppresses the deeper condens…     

Surprisingly efficient catalytic Cr-mediated coupling reactions

[reaction: see text] With use of 1 mol % of Cr catalyst 5, surprisingly efficient Cr-mediated couplings of aldehydes with various types of nucleophiles have been realized. The catalyst set of Cr catalyst 5 and Ni catalyst 4 is used for alkenylation, alkynylation, and arylation, whereas the catalyst set of Cr catalyst 5 and CoPc (cobalt phthalocyanine) is used for 2-haloallylation, alkylation, and propargylation. Only the Cr catalyst 5 is required for allylation. The reaction rates in DME and THF have been found significantly faster than that in MeCN.     

Mediated amperometric biosensor for hypoxanthine based on a hydroxymethylferrocene-modified carbon paste electrode

An amperometric enzyme electrode for the determination of hypoxanthine in fish meat is described. The hypoxanthine sensor was prepared from xanthine oxidase immobilized by covalent binding to cellulose triacetate and a carbon paste electrode containing hydroxymethylferrocene. The xanthine oxidase membrane was retained behind a dialysis membrane at a carbon paste electrode. The sensor showed a current response to hypoxanthine due to the bioelectrocatalytic oxidation of hypoxanthine, in which hydroxymethyiferrocene served as an electron-transfer mediator. The limit of detection is 6 × 10^?7 M, the relative standard deviation is 2.8% (n=28) and the response is linear up to 7 × 10^?4 M. The sensor responded rapidly to a low hypoxanthine concentration (7 × 10^?4 M), the steady-state current response being achieved in less than 1 min, and was stable for more than 30 days at 5 ° C. Results for tuna samples showed good agreement with the value determined by the conventional method.