Differential genotoxic effects of subchronic exposure to ethyl tertiary butyl ether in the livers of <Emphasis Type="Italic">Aldh2</Emphasis> knockout and wild-type mice

Ethyl tertiary butyl ether (ETBE) is used as an additive to gasoline to reduce carbon monoxide emissions in some developed countries. So far, ETBE was not found with positive results in many genotoxic assays. This study is undertaken to investigate the modifying effects of deficiency of aldehyde dehydrogenase 2 (ALDH2) on the toxicity of ETBE in the livers of mice. Eight-week-old wild-type (WT) and Aldh2 knockout (KO) C57BL/6 mice of both sexes were exposed to 0, 500, 1,750, and 5,000 ppm ETBE for 6 h/day with 5 days per weeks for 13 weeks. Histopathology assessments and measurements of genetic effects in the livers were performed. Significantly increased accidences of centrilobular hypertrophy were observed in the livers of WT and KO mice of both sexes in 5,000 ppm group; there was a sex difference in centrilobular hypertrophy between male and female KO mice, with more severe damage in the males. In addition, DNA strand breaks, 8-hydroxyguanine DNA-glycosylase (hOGG1)-modified oxidative base modification, and 8-hydroxydeoxyguanosine as genetic damage endpoints were significantly increased in three exposure groups in KO male mice, while these genotoxic effects were only found in 5,000 ppm group of KO female mice. In WT mice, significant DNA damage was seen in 5,000 ppm group of male mice, but not in females. Thus, sex differences in DNA damage were found not only in KO mice, but also in WT mice. These results suggest that ALDH2 polymorphisms and sex should be taken into considerations in predicting human health effects of ETBE exposure.     

Preliminary trial of syndromic surveillance to early detection of nosocomial infection outbreak

OBJECTIVE: To detect nosocomial outbreaks early we construct syndromic surveillance for inpatients with fever, respiratory symptoms, diarrhea, vomiting, or rash and evaluate it statistically. METHODS AND MATERIALS: In hospital using electronic medical records since August 1999, we studied the number of inpatients with a certain symptoms from 1999 to 2005. To prospectively detect outbreaks after January 1, 2005, we first estimated the baseline using data from August 1, 1999 to the day before any given day. We then predicted the number of patients on the day and judge whether an outbreak has occurred, evaluating this by checking it sensitivity and specificity to detect outbreaks other than those with previous patterns. RESULTS: From August 1999 to December 2005, 115,532 patients had fever, 126,443 respiratory symptoms, 87,923 diarrhea, 32,858 vomiting, and 11,212 In 2005, in prospective detection, 23,617 had fever, 23,698 respiratory symptoms, 14,671 diarrhea, 5,893 vomiting, and 2,486 rash. DISCUSSION: This hospital had a nosocomial Noro virus outbreak on January 27, 2005. Syndromic surveillance identified an outbreak of vomiting at a 0.1% criterion. Our system thus detects nosocomial outbreaks and is of practical use. The next step will be ward-by-ward examination, after which we will experiment with rapid information collection, analysis, reports of results, and investigation by infection control teams.     

Cost-effectiveness analysis of routine mumps immunization in Japan

OBJECTIVE: Mumps immunization is not included in routine immunization in Japan. We measured the cost-effectiveness of routine immunization. METHODS: We surveyed outpatients prospectively from June 15, 2004, for 19 months in an area with a population of 100,000. Almost all of the 11 pediatric clinics and hospitals in this area cooperated. In 2006, we retrospectively surveyed all inpatients hospitalized for more than 24 hours and dying of mumps. RESULTS: We collected data from 189 doctors who rated outpatients and 112 families. The disease burden for outpatients including family nursing was estimated to be 47.1 billion yen nationwide. We estimated the total number of inpatients as 4,596. The disease burden of inpatients including the cost of family nursing was estimated to be 1.35 billion yen. Adding cases of sequelae and death, the total disease burden was estimated to be 52.5 billion yen. The incremental benefit cost ratio for routine immunization is higher than 1 even in the lower bounds of the 95% confidence interval. DISCUSSION AND CONCLUSIONS: The incremental benefit cost ratio shows that the additional benefit due to routine immunization exceeds additional cost, emphasizing the benefits of routine mumps immunization.     

Permethrin may disrupt testosterone biosynthesis via mitochondrial membrane damage of Leydig cells in adult male mouse

Permethrin, a popular synthetic pyrethroid insecticide used to control noxious insects in agriculture, forestry, households, horticulture, and public health throughout the world, poses risks of environmental exposure. Here we evaluate the reproductive toxicity of cis-permethrin in adult male ICR mice that were orally administered cis-permethrin (0, 35, or 70 mg/kg d) for 6 wk. Caudal epididymal sperm count and sperm motility in the treated groups were statistically reduced in a dose-dependent manner. Testicular testosterone production and plasma testosterone concentration were significantly and dose-dependently decreased with an increase in LH, and a significant regression was observed between testosterone levels and cis-permethrin residues in individual mice testes after exposure. However, no significant changes were observed in body weight, reproductive organ absolute and relative weights, sperm morphology, and plasma FSH concentration after cis-permethrin treatment. Moreover, cis-permethrin exposure significantly diminished the testicular mitochondrial mRNA expression levels of peripheral benzodiazepine receptor (PBR), steroidogenic acute regulatory protein (StAR), and cytochrome P450 side-chain cleavage (P450scc) and enzyme and protein expression levels of StAR and P450scc. At the electron microscopic level, mitochondrial membrane damage was found in Leydig cells of the exposed mouse testis. Our results suggest that the insecticide permethrin may cause mitochondrial membrane impairment in Leydig cells and disrupt testosterone biosynthesis by diminishing the delivery of cholesterol into the mitochondria and decreasing the conversion of cholesterol to pregnenolone in the cells, thus reducing subsequent testosterone production.     

Quality of Umbilical Cord Blood CD34<Superscript>+</Superscript> Cells in a Double-Compartment Freezing Bag Cryopreserved without a Rate-Controlled Programmed Freezer

The aim of this study was to evaluate how a simple method of cryopreservation influences the quality of CD34+ cells in umbilical cord blood (UCB). The cells were dispensed into a double-compartment freezing bag, cryopreserved at -85 degrees C without a rate-controlled programmed freezer, and stored in the liquid phase of nitrogen. The viability of the CD34+ cells before freezing and after thawing was assessed by flow cytometry with 7-aminoactinomycin D and by colony-forming assays. Twenty UCB units cryopreserved for a median of 92 days were analyzed. Mean CD34+ cell viabilities before freezing were 99.8% +/- 0.4% and after thawing were 99.5% +/- 0.8% in large chambers, 99.6% +/- 0.5% in small chambers, and 99.4% +/- 0.6% in sample tubes. The mean values from colony-forming assays of the viable CD34+ cells before freezing were 30.7 +/- 6.8 (colony-forming units-granulocyte-macrophage [CFU-GM] per 100 viable CD34+ cells) and 68.5 +/- 14.8 (total CFUs per 100 viable CD34+ cells). The CFU-GM and total CFU values after thawing were, respectively, 32.7 +/- 9.0 and 66.0 +/- 13.4 in large chambers, 32.4 +/- 8.1 and 64.5 +/- 16.1 in small chambers, and 30.9 +/- 5.4 and 64.7 +/- 12.4 in sample tubes. The results of the colony-forming assays before freezing and after thawing were not significantly different. Our findings overall indicated that our simple method for the cryopreservation of UCB cells without a rate-controlled programmed freezer does not impair the clonogenic capacity of UCB progenitor cells. This cryopreservation method could provide cellular products adequate for hematopoietic stem cell transplantation.     

Use of an ultrasound blood-mimicking fluid for Doppler investigations of turbulence in vitro

Turbulence is an important factor in the assessment of stenotic disease and a possible causative mechanism for thromboembolism. Previous Doppler studies of turbulence have typically used whole-blood preparations or suspensions of erythrocytes. Recently, a water-glycerol based blood-mimicking fluid (BMF) has been developed for use in Doppler ultrasound studies. This fluid has desirable ultrasound properties but it has not previously been described during in vitro investigations of turbulence intensity. We report on investigations of grid-generated and constrained-jet turbulence in an in vitro test system. The BMF was found to generate significant levels of turbulence during steady flow at physiological flow rates, producing turbulent patterns in the distal region that were consistent with previous studies. Turbulence intensity increased significantly with flow rate (p < 0.005) for both the constrained jet and the constrained grid. Based on our observations, we conclude that a water-glycerol based BMF provides a suitable working fluid during in vitro investigations of turbulence using Doppler ultrasound.     

Di(2-ethylhexyl)phthalate induces hepatic tumorigenesis through a peroxisome proliferator-activated receptor alpha-independent pathway

Di(2-ethylhexyl)phthalate (DEHP), a commonly used industrial plasticizer, causes liver tumorigenesis presumably via activation of peroxisome proliferator-activated receptor alpha (PPARalpha). The mechanism of DEHP tumorigenesis has not been fully elucidated, and to clarify whether DEHP tumorigenesis is induced via PPARalpha, we compared DEHP-induced tumorigenesis in wild-type and Pparalpha-null mice. Mice of each genotype were divided into three groups, and treated for 22 months with diets containing 0, 0.01 or 0.05% DEHP. Surprisingly, the incidence of liver tumors was higher in Pparalpha-null mice exposed to 0.05% DEHP (25.8%) than in similarly exposed wild-type mice (10.0%). These results suggest the existence of pathways for DEHP-induced hepatic tumorigenesis that are independent of PPARalpha. The levels of 8-OHdG increased dose-dependently in mice of both genotypes, but the degree of increase was higher in Pparalpha-null than in wild-type mice. NFkappaB levels also significantly increased in a dose-dependent manner in Pparalpha-null mice. The protooncogene c-jun-mRNA was induced, and c-fos-mRNA tended to be induced only in Pparalpha-null mice fed a 0.05% DEHP-containing diet. These results suggest that increases in oxidative stress induced by DEHP exposure may lead to the induction of inflammation and/or the expression of protooncogenes, resulting in a high incidence of tumorigenesis in Pparalpha-null mice.     

8-Hydroxydeoxyguanosine levels in human leukocyte and urine according to exposure to organophosphorus pesticides and paraoxonase 1 genotype

Objective In order to investigate a role of paraoxonase 1 (PON1) polymorphism in organophosphorus (OP)-induced 8-hydroxydeoxyguanosine (8-OHdG) levels, urinary metabolites of OP, PON1 genotypes, and 8-OHdG levels in leukocyte and urine were measured in OP indoor insecticide sprayers and controls in summer and winter. Methods The study population contained 18 male sprayers and age-matched 18 male controls. Sprayers were primarily exposed to OP insecticides (mainly fenitrothion, dichlorvos, chlorpyrifos, and diazinon), and partially to pyrethroids (mainly permethrin) and carbamates (mainly propoxur). Urinary metabolites of OP were measured by gas chromatography-mass spectrometry. 8-OHdG levels in leukocyte and urine were measured by ELISA kit. PON1 genotype was identified using allele-specific fluorogenic TaqMan probes. Results The mean concentrations of urinary dimethyl phosphate (DMP) and total dialkyl phosphates (DAP) in summer and those of 8-OHdG in summer and winter were significantly higher in OP sprayers than controls. This resulted in a significant positive correlation between 8-OHdG levels and urinary DMP or DAP, suggesting a correlation between OP metabolites and production of oxidative stress. Of PON1 genotypes, incidences of Q/Q, Q/R, and R/R types were 17, 39, and 44% in OP sprayers and controls, respectively. Although PON1 polymorphism did not contribute to the leukocyte and urinary 8-OHdG levels, the urinary OP metabolite concentrations in summer showed a significant decrease as the number Q allele decreased. Conclusion These results indicate that an increase in OP metabolites is associated with a high level of oxidative stress in OP sprayers, although the contribution of the PON1 polymorphism to the metabolism of OP is still unclear.     

Simultaneous changes in high-fat and high-cholesterol diet-induced steatohepatitis and severe fibrosis and those underlying molecular mechanisms in novel SHRSP5/Dmcr rat

Objectives

The aim of this study was to identify the molecular mechanisms underlying high-fat and high-cholesterol (HFC) diet-induced steatohepatitis and associated liver fibrosis progression in a novel stroke-prone, spontaneously hypertensive 5/Dmcr (SHRSP5/Dmcr) rat model.

Methods

SHRSP5/Dmcr rats were given the control or HFC-diet for 2, 8, and 16 weeks. Plasma and hepatic gene expression of key molecules involved in fatty acid oxidation, inflammation, oxidative stress, and fibrosis were subsequently analyzed.

Results

Rats fed the HFC-diet showed increased plasma tumor necrosis factor-α (TNF-α) and hepatic p50/p65 signals, but reduced hepatic Cu²⁺/Zn²⁺-superoxide dismutase across the treatment period and reduced plasma total adiponectin at 8 weeks. In HFC-diet-fed rats, transforming growth factor-β1 (TGF-β1) was elevated prior to the appearance of obvious liver fibrosis pathology at 2 weeks, followed by elevations in platelet-derived growth factor-B (PDGF-B) and α-smooth muscle actin (α-SMA), corresponding to evident liver fibrosis, at 8 weeks and by α₁ type I collagen production at 16 weeks. The HFC-diet increased hepatic total cholesterol accumulation, although hepatic triglyceride declined by 0.3-fold from 2 to 16 weeks due to reduced hepatic triglyceride synthesis, as suggested by the diacylglycerol acyltransferase 1 and 2 measurements.

Conclusions

TNF-α and p50/p65 molecular signals appeared to be major factors for HFC-diet-induced hepatic inflammation and oxidative stress facilitating liver disease progression. While the up-regulation of TGF-β1 prior to the appearance of any evident liver fibrosis could be an early signal for progressive liver fibrosis, elevated PDGF-B and α-SMA levels signified evident liver fibrosis at 8 weeks, and subsequent increased α₁ type I collagen production and reduced triglyceride synthesis indicated extensive liver fibrosis at 16 weeks in this novel SHRSP5/Dmcr model.

Electronic supplementary material

The online version of this article (doi:10.1007/s12199-012-0273-y) contains supplementary material, which is available to authorized users.