Liver injury induced by thirty- and fifty-nanometer-diameter silica nanoparticles.

Nano-size silica material is a promising reagent for disease diagnosis, cosmetics, and the food industry. For the successful application of nanoparticle materials in bioscience, evaluation of nano-size material toxicity is important. We previously found that nano-size silica particles caused acute liver failure in mice.

Deficient of a clock gene, brain and muscle Arnt-like protein-1 (BMAL1), induces dyslipidemia and ectopic fat formation.

A link between circadian rhythm and metabolism has long been discussed. Circadian rhythm is controlled by positive and negative transcriptional and translational feedback loops composed of several clock genes. Among clock genes, the brain and muscle Arnt-like protein-1 (BMAL1) and circadian locomotor output cycles kaput (CLOCK) play important roles in the regulation of the positive rhythmic transcription.

Aryl hydrocarbon receptor functions as a potent coactivator of E2F1-dependent trascription activity.

The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor that mediates a spectrum of toxic and biological effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin and related compounds. Several reports have shown that the AhR plays an important role in the control of cell-cycle progression, and this function is thought to be partly associated with the tumor promotion activity of dioxin. However, the underling mechanisms are not fully understood.

Comparative study of hydrogen peroxide- and 4-hydroxy-2-nonenal-induced cell death in HT22 cells.

Several studies have indicated that lipid peroxidation often occurs in response to oxidative stress, and that many aldehydic products including 4-hydroxy-2-nonenal (HNE) are formed when lipid hydroperoxides break down. In order to clarify the mechanism of oxidative stress-induced neuronal death in the nervous system, we investigated H(2)O(2)- and HNE-induced cell death pathways in HT22 cells, a mouse hippocampal cell line, under the same experimental conditions. Treatment with H(2)O(2) and HNE decreased the viability of these cells in a time- and concentration-dependent manner.

Characterization of the molecular clock in mouse peritoneal macrophages.

Macrophages play essential roles in the innate immune system. In this study, we show that macrophage functions such as phagocytosis and cytokine/chemokine expressions display a circadian rhythm that is regulated by a molecular clock. Phagocytosis, a crucial early reaction by which macrophages protect their host against foreign particles, exhibited a circadian variation that peaks during the light period and bottoms during the dark period.

Transcriptional regulation of the hypoxia inducible factor-2alpha (HIF-2alpha) gene during adipose differentiation in 3T3-L1 cells.

Adipose differentiation is regulated by coordination of several signaling pathways and transcription factors. We recently showed that Hypoxia inducible factor-2alpha (HIF-2alpha) plays several supporting roles in adipose differentiation and adipocytes functions including regulation of glucose uptake followed by lipid synthesis. HIF-2alpha expression is increased during adipogenesis, indicating that its up-regulation is necessary for execution of adipogenesis and maintenance of mature adipocytes functions.

Evaluation of some halogen biocides using a microbial biofilm system.

A simple method for the formation of microbial biofilms of three species, Pseudomonas fluorescens, Pseudomonas aeruginosa, and Klebsiella pneumoniae, on a small glass slide was established, and its suitability for evaluation of disinfectant efficacy was examined. The biofilms formed were observed in situ by confocal laser scanning microscopy (CLSM). Using the biofilms established, biocidal efficacy of several halogen biocides, such as hypochlorite (HOCl), bromochlorodimethylhydantoin (Br, Cl-DMH), ammonia monochloramine (NH2Cl), a stabilized hypobromite biocide named STABREX, and a mixed solution of NH4Br and HOCl, was evaluated.

Brain and muscle Arnt-like protein-1 (BMAL1), a component of the molecular clock, regulates adipogenesis.

Brain and muscle Arnt-like protein-1 (BMAL1; also known as MOP3 or Arnt3) is a transcription factor known to regulate circadian rhythm. Here, we established its involvement in the control of adipogenesis and lipid metabolism activity in mature adipocytes. During adipose differentiation in 3T3-L1 cells, the level of BMAL1 mRNA began to increase 4 days after induction and was highly expressed in differentiated cells.

Occurrence and production of chloramines in the chlorination of creatinine in aqueous solution.

Occurrence and production of stable chloramines in the chlorination of creatinine, a constituent of perspiration and urine, in aqueous media were studied. Creatinine (5 x 10(-5)M) was treated with free chlorine in aqueous solutions at molar ratios of 0.5-8 (chlorine/creatinine) at pH 7.

EPAS1 promotes adipose differentiation in 3T3-L1 cells.

Adipose differentiation is regulated by several transcription factors, such as the CAAT/enhancer-binding protein family and peroxisome proliferator activator (PPAR) gamma2. Several recent studies have shown that the basic helix-loop-helix-PAS superfamily is also involved in the regulation of adipose differentiation. In this study, we investigated the roles played by EPAS1 (endothelial PAS domain protein 1) in adipogenesis.

Development of a headspace GC/MS analysis for carbonyl compounds (aldehydes and ketones) in household products after derivatization with o-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine.

Carbonyl compounds (aldehydes and ketones) are suspected to be among the chemical compounds responsible for Sick Building Syndrome and Multiple Chemical Sensitivities. A headspace gas chromatography/mass spectrometry (GC/MS) analysis for these compounds was developed using derivatization of the compounds into volatile derivatives with o-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine (PFBOA). For GC/MS detection, two ionization modes including electron impact ionization (EI) and negative chemical ionization (NCI) were compared.

Transcriptional regulation of the AhR gene during adipose differentiation.

The aryl hydrocarbon receptor (AhR) mediates a spectrum of toxicological and biological effects of dioxins. Studies on tissue distribution of the AhR in developing and adult animals demonstrated that the AhR is expressed in a tissue-specific and developmentally specific manner. Also, the expression level of the AhR in culture cells varies more than 50-fold among cell lines.

Overexpression of the aryl hydrocarbon receptor (AhR) accelerates the cell proliferation of A549 cells.

The arylhydrocarbon receptor (AhR) is a ligand-activated transcription factor that mediates a spectrum of toxic and biological effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and related compounds. Although the physiological ligand for the AhR has not yet been identified, several reports have suggested that the AhR may play important roles not only in the regulation of xenobiotic metabolism but also in the maintenance of homeostatic functions [Singh et al. (1996) Arch.

Effects of isocyanuric acid on the monochlorodimedone chlorinating rates with free chlorine and ammonia chloramine in water.

Changes in monochlorodimedone (MCD) chlorinating rates with free chlorine (mixture of HOCl and OCl-) and ammonia monochloramine (NH2Cl) in water at pH 7 by the addition of isocyanuric acid (H3Cy) were determined at room temperature. Decreases in MCD absorbance at 290nm in equimolar (0.04mM) reactions of MCD and free available chlorine solutions containing H3Cy (0.