Metabolism and physiologically based pharmacokinetic modeling of flumioxazin in pregnant animals

A physiologically based pharmacokinetic (PBPK) model was developed to predict the concentration of flumioxazin, in the blood and fetus of pregnant humans during a theoretical accidental intake (1000 mg/kg). The data on flumioxazin concentration in pregnant rats (30 mg/kg po) was used to develop the PBPK model in pregnant rats using physiological parameters and chemical specific parameters. The rat PBPK model developed was extrapolated to a human model. Liver microsomes of female rats and a mixed gender of humans were used for the in vitro metabolism study. To determine the % of flumioxazin absorbed after administration at a dose of 1000 mg/kg assuming maximum accidental intake, the biliary excretion study of [phenyl-U-¹⁴C]flumioxazin was conducted in bile duct-cannulated female rats (Crl:CD (SD)) to collect and analyze the bile, urine, feces, gastrointestinal tract, and residual carcass. The % of flumioxazin absorbed at a dose of 1000 mg/kg in rats was low (12.3%) by summing up ¹⁴C of the urine, bile, and residual carcass. The pregnant human model that was developed demonstrated that the maximum flumioxazin concentration in the blood and fetus of a pregnant human at a dose of 1000 mg/kg po was 0.86 μg/mL and 0.68 μg/mL, respectively, which is much lower than K_m (202.4 μg/mL). Because the metabolism was not saturated and the absorption rate was low at a dose of 1000 mg/kg, the calculated flumioxazin concentration in pregnant humans was thought to be relatively low, considering the flumioxazin concentration in pregnant rats at a dose of 30 mg/kg. For the safety assessment of flumioxazin, these results would be useful for further in vitro toxicology experiments.     

Urinary 1-hydroxypyrene as a comprehensive carcinogenic biomarker of exposure to polycyclic aromatic hydrocarbons: a cross-sectional study of coke oven workers in China

Purpose

Polycyclic aromatic hydrocarbons (PAHs) are multiple compounds that include many carcinogens. We conducted a cross-sectional study in steel plant workers in Anshan, China, to identify biomarkers that reflect the carcinogenicity of PAHs.

Methods

Subjects were 57 workers and 20 controls. Level of personal exposure to PAHs was measured using GC–MS. In accordance with the assessment methods defined by the United States Environmental Protection Agency (US EPA), 15 PAHs were selected for the analysis. For the measurement of urinary metabolites, urine samples were treated with β-glucuronidase and analyzed using HPLC with a fluorescence detector.

Results

The mean range of personal exposure to 15 PAHs (total PAHs) was 178.85, 47.08–1,329.45 (geometric mean, 5th and 95th percentile) μg/m³. Ten known urinary metabolites (1-hydroxynaphthalene, 2-hydroxynaphthalene, 2-hydroxyfluorene, 1-hydroxyphenanthrene, 3-hydroxyphenanthrene, 9-hydroxyphenanthrene, 1-hydroxypyrene, 3-hydroxybenz[a]anthracene, 6-hydroxychrysene, and 3-hydroxybenzo[a]pyrene) and four unknown peaks were detected. The highest correlation was between total PAHs and urinary 2-hydroxynaphthalene (Spearman r = 0.716, P < 0.01). Among the detected urinary metabolites, 2-hydroxyfluorene, 1-hydroxyphenanthrene, 3-hydroxyphenanthrene, and 1-hydroxypyrene were found to correlate significantly with the “Σ carcinogenic potency of PAHs” (sum of seven carcinogenic PAHs calculated from the levels of personal PAHs and relative potency factors), and with the greatest correlation found for 1-hydroxypyrene (Spearman r = 0.630, P < 0.01).

Conclusions

The analysis of personal exposure to 15 PAHs and 10 urinary metabolites, and calculation of Σ carcinogenic potency, indicated that urinary 1-hydroxypyrene was the most comprehensive carcinogenic biomarker of exposure to PAHs.     

Monochloroacetic acid inhibits liver gluconeogenesis by inactivating glyceraldehyde-3-phosphate dehydrogenase

We previously reported that a lethal dose of monochloroacetate (MCA) causes severe hypoglycemia and lactic acidosis. MCA has been thought to inhibit mitochondrial aconitase; however, the exact effect of MCA on hepatic glucose metabolism is not clear. In this study, we investigated the effects of MCA on liver gluconeogenesis using an isolated perfused rat liver system. Gluconeogenesis from 2.5 mM lactate was inhibited by 1 mM MCA and was completely abolished after 2 h of perfusion. Levels of citric acid cycle intermediates such as citrate, isocitrate, and 2-oxoglutarate (2-OG) were significantly reduced by MCA. The finding that the levels of citrate and 2-OG were similarly reduced (to 31 and 36% of control, respectively) indicates that aconitase was not inhibited by MCA. On the contrary, gluconeogenesis from glycerol, which can be converted to glucose without glyceraldehyde-3-phosphate dehydrogenase (GAPDH), was not inhibited by MCA. GAPDH was inactivated by MCA in vitro, but enolase, phosphoglycerate mutase, and phosphoglycerate kinase were not inactivated at the same or higher concentrations of MCA. Furthermore, GAPDH activity in the MCA-perfused liver decreased to 33-42% of control and that in the liver of rats exposed to MCA was reduced to 19% of control. We concluded that MCA inactivates GAPDH, and this is the cause of the inhibition of liver gluconeogenesis.     

Lack of combination hepatocarcinogenicity of harman, norharman and amitrole when given with NaNO2 in the rat

N-nitrosocompounds, which induce cancers in various organs, may be formed endogenously with intake of amino compounds such as secondary amines and sodium nitrite (NaNO(2)) in combination. The present study was performed to investigate whether three amino compounds, 1-methyl-9H-pyrido[3,4-b]indole (harman), 9H-pyrido[3,4-b]indole (norharman) and 2-amino-1,3,4-triazole (amitrole), might be converted in vivo to compounds capable of promoting hepatocarcinogenesis when given with NaNO(2). However, in an 8-week model, no modifying potential was evident in terms of numbers and areas of putative preneoplastic glutathione S-transferase placental form (GST-P)-positive foci in any of the groups receiving paired treatments. These results demonstrate that combinations of harman, norharman and amitrole with NaNO(2) lack promoting effects for liver carcinogenesis in our medium-term bioassay system.     

Topical administration of HSV gD-IL-2 DNA is highly protective against murine herpetic stromal keratitis.

PURPOSE: To evaluate the immunopreventive effect of eyedrops that contain gD-IL-2 DNA (a chimeric gene of the glycoprotein D gene of herpes simplex virus type I (HSV-1) and human interleukin-2 (IL-2) on murine herpetic keratitis. METHODS: A plasmid containing gD-IL-2 (pHDLneo1) was constructed. The eyedrops containing 90 microg/10 microL of the DNA was instilled bilaterally into the conjunctival sacs of BALB/c mice on days 0 and 7. Three weeks after the last administration, neutralizing antibody, delayed-type hypersensitivity (DTH), and 51Cr-release from infected targeted cells by lymphocytes from the cervical lymph nodes and spleen were determined. Immunized mice were challenged with HSV-1, after which the clinical signs of the corneal epithelia and stroma were scored. RESULTS: Specific neutralizing antibody was raised and prominent DTH reaction was elicited from immunized mice. Lymphocytes obtained from the local lymph nodes and spleen vigorously potentiated the cytotoxic activity against the virus-infected cells. Clinically, the development of stromal keratitis was completely inhibited, but prevention or reduction of HSV-1 epithelial lesions was not demonstrated statistically. CONCLUSION: Topical immunization with a DNA vaccine encoding gD-IL-2 totally prevented the development of herpetic stromal keratitis. This procedure is a simple and convenient method for possible clinical application in the future.     

Factors associated with good self-rated health of non-disabled elderly living alone in Japan: a cross-sectional study

Background  

Self-rated health (SRH) is reported as a reliable predictor of disability and mortality in the aged population and has been studied worldwide to enhance the quality of life of the elderly. Nowadays, the elderly living alone, a particular population at great risk of suffering physical and mental health problems, is increasing rapidly in Japan and could potentially make up the majority of the aged population. However, few data are available pertaining to SRH of this population. Given the fact that sufficient healthcare is provided to the disabled elderly whereas there is little support for non-disabled elderly, we designed this population-based survey to investigate SRH of non-disabled elderly living alone and to identify the factors associated with good SRH with the purpose of aiding health promotion for the elderly.     

Functional expression of TWEAK in human colonic adenocarcinoma cells

The TNF-like weak inducer of apoptosis (TWEAK) can induce diverse cellular responses, including cell death, inflammation, migration, and proliferation in various transformed cell lines. We investigated TWEAK sensitivity, TWEAK effects on nuclear factor-kappaB activation, and expression of TWEAK in the HT-29, LS180, SK-CO-1 and SW480 human colonic adenocarcinoma cell lines, all of which express the TWEAK receptor (Fn14). TWEAK alone induced cell death in SW480 cells and induced cell death of HT-29 cells after addition of IFN-gamma, actinomycin D or cycloheximide. TWEAK did not affect cell viability of LS-180 or SK-CO-1 cells. Activation of NF-kappaB was not obviously influenced by TWEAK in any of the cell lines. All four human colonic adenocarcinoma cell lines constitutively expressed TWEAK mRNA, protein and membrane-bound TWEAK antigen, as detected by RT-PCR, Western blotting and flow cytometry. Stimulation by an anticancer drug (camptothecin) augmented cell surface expression of TWEAK and all human colonic adenocarcinoma tissue samples studied (n=59) demonstrated positive staining for TWEAK antigen. Soluble TWEAK was detected in culture medium of these cell lines by ELISA and conditioned medium from SW480 cells incubated with anti-TWEAK antibody significantly inhibited endothelial cell tube formation in Matrigels. Thus, functional expression of TWEAK from human colonic adenocarcinoma cells may contribute to neovascularization.     

Loss of function of p16 gene and prognosis of pulmonary adenocarcinoma

BACKGROUND: Stepwise progression of peripheral-type lung adenocarcinoma was characterized morphologically and was related to prognosis. Expression of the tumor suppressor gene p16 in pulmonary adenocarcinoma decreased, mainly as a result of aberrant methylation of the CpG islands of the promoter region. METHODS: Aberrant methylation status of the p16 promoter region, the expression of its product, and loss of heterozygosity (LOH) on 9p21 were examined in surgically resected lung specimens from 57 patients (28 males and 29 females) with peripheral-type lung adenocarcinoma measuring 相似文献