Levels of volatile organic compounds in homes in Dalian,China

This paper measured selected individual volatile organic compounds (VOCs), including formaldehyde, in residences in Dalian, evaluated the association between the apartment characteristics and VOC concentrations, and explored the associations between chemicals and sick building syndrome (SBS). Higher VOC concentrations were measured indoors than outdoors in summer (August to September) and winter (January to March) in Dalian, and there were no strong correlations between the indoor and outdoor concentrations of most VOCs. This indicates the dominance of indoor sources as compared to outdoor sources. Formaldehyde was the most abundant compound in this study, followed by toluene, benzene, xylene, and styrene. These pollutants increase the occurrence of SBS. Thus, the VOC levels in dwellings in Dalian should be regulated, in view of SBS risks.     

Biological monitoring of pyrethroid exposure of pest control workers in Japan

Synthetic pyrethroids such as cypermethrin, deltamethrin and permethrin, which are usually used in pest control operations, are metabolized to 3-phenoxybenzoic acid (3-PBA) and excreted in urine. Though 3-PBA can be used to assess exposure to pyrethroids, there are few reports describing urinary 3-PBA levels in Japan. This study aimed to investigate the seasonal variation of the exposure levels of pyrethroids and the concentration of urinary 3-PBA among pest control operators (PCOs) in Japan. The study subjects were 78 and 66 PCOs who underwent a health examination in December 2004 and in August 2005, respectively. 3-PBA was determined using gas chromatography-mass spectrometry. The geometric mean concentration of urinary 3-PBA in winter (3.9 microg/g creatinine) was significantly lower than in summer (12.2 microg/g creatinine) (p<0.05). Geometric mean concentrations of urinary 3-PBA in the spraying workers and the not-spraying workers within 2 d before the survey were 5.4 microg/g creatinine and 0.9 microg/g creatinine for winter with a significant difference between the groups (p<0.05), and 12.3 microg/g creatinine and 8.7 microg/g creatinine for summer (p>0.05), respectively. A significant association of 3-PBA levels and pyrethroid spraying was thus observed only in winter. In conclusion, the results of the present study show that the exposure level of pyrethroids among PCOs in Japan assessed by monitoring urinary 3-PBA was higher than that reported in the UK but comparable to that in Germany. Further research should be accumulated to establish an occupational reference value in Japan.     

Differential effects of aging, drinking and exercise on serum cholesterol levels dependent on the PPARA-V227A polymorphism

Peroxisome proliferator-activated receptor alpha (PPARA alpha) plays a pivotal role in lipid metabolism. Our previous study reported that PPARA-V227A was a major polymorphism in Japanese, which was associated with markedly lower serum total cholesterol (TC) levels, which were significantly affected by alcohol drinking compared to subjects with the wild-type (PPARA-WT) allele. However, serum lipids are also associated with aging and exercise frequency. The objective of the present study was to evaluate the relationship between PPARA-V227A and these factors. Genetic analysis of the polymorphism was performed in 1058 Japanese men and 281 women, and the relationship with aging, drinking and exercise on serum lipids was analyzed in 989 men and 245 women after exclusion criteria had been applied. In men, drinking increased high-density lipoprotein cholesterol (HDL-C) levels in both PPARA-WT and A227 carriers, but to a significantly higher degree in the latter. In women, TC and low-density lipoprotein cholesterol (LDL-C) levels in the A227 carriers drinking at least once a week were significantly higher than in PPARA-WT carriers. TC and LDL-C levels in males with PPARA-WT increased with aging regardless of drinking habit, while LDL-C levels in the A227 drinking carriers were significantly lower in 45-yr-old or older subjects than in 35- to 45-yr-olds. In addition, no effect of exercising was observed in the A227 carriers, while increase in the HDL-C of the PPARA-WT carriers was exercise frequency dependent. These results suggest that the influence of drinking, aging or exercise on TC, LDL-C and HDL-C levels in the A227 carriers may be different from those in the PPARA-WT subjects.     

3-Methyl-4-nitrophenol metabolism by uridine diphosphate glucuronosyltransferase and sulfotransferase in liver microsomes of mice, rats, and Japanese quail (Coturnix japonica)

3-Methyl-4-nitrophenol (PNMC) is a component of diesel exhaust particles and one of the major breakdown products of the insecticide fenitrothion. This chemical has a high potential for reproductive toxicity in Japanese quail (Coturnix japonica) and rats. Because PNMC inhaled by the body is metabolized by uridine diphosphate glucuronosyltransferase (UGT) and sulfotransferase, we investigated these enzyme activities in the hepatic microsomes and cytosols of quail (as a model of wild birds) and compared these activities with those of rats and mice as models of ecological and human risk assessment. The maximum velocity of the UGT for PNMC in quail was 12.7 nmol/min/mg, which was one third and one fourth those of rats and mice, respectively. The Michaelis-Menten constant of UGT for PNMC in quail was 0.29 mM, which was 1.3- and 1.8-fold higher than that in mice and rats, respectively, but not significantly different. In accordance with these results, UGT activities for PNMC were lowest in quail, with those in mice and rats being 4.4- and 2.7-fold higher, respectively. Sulfotransferase activity for PNMC was considerably less than that of UGT in all animals, including quail; no significant differences in the activities were found among mice, rats, and quail. These results suggest that glucuronidation may be involved primarily in PNMC elimination from wild birds as well as mammals and that the UGT activity in quail is less than that in the rodents.     

Reproductive toxicity of ethylene glycol monoethyl ether in Aldh2 knockout mice

Ethylene glycol monoethyl ether (EGEE) can cause damage to testes and sperm, and its metabolites are believed to play an important role in its toxicity. Aldehyde dehydrogenase 2 (ALDH2) is involved in the metabolism of this chemical. To investigate whether and how the enzyme affects the toxicity of EGEE, we conducted experiments comparing Aldh2 knockout mice with wild-type mice. Administration of EGEE at 100 and 600 mg/kg/day for one week did not induce any significant change in the weight and body weight ratios of testes, prostate and epididymides in either Aldh2 knockout or wild-type mice. However, motion of sperm from the spermaduct, as analyzed with a Hamilton-Thorne Sperm analyzer, was slightly decreased in the low dose group, and significantly lower in the high dose group; and the percentage of progressive sperm was also reduced in the two EGEE groups. This effect of EGEE treatment was observed in the wild-type, but not in the Aldh2 knockout mice. Sperm motion from the cauda epididymides was not affected. On the other hand, the concentration of ethoxyacetic acid, a metabolite of EGEE, in 24 h pooled urine of EGEE-treated Aldh2 knockout mice was not significantly lower than that of the wild-type mice on most days of urine sampling. These results suggest that inactivation of the ALDH2 enzyme due to gene mutation may be linked to differences in the susceptibility to EGEE-induced sperm toxicity.     

A thin-walled carotid vessel phantom for Doppler ultrasound flow studies

A technique is discussed for producing a robust ultrasound (US)-compatible flow phantom that consists of a thin-walled silicone-elastomer vessel with a lumen of arbitrary geometry, embedded in an agar-based tissue-mimicking material (TMM). The TMM has an acoustic attenuation of 0.56 dB cm(-1) MHz(-1) at 5 MHz, with nearly linear frequency-dependence and acoustic velocity of 1539 +/- 4 m s(-1). The vessel-mimicking material (VMM) has an acoustic attenuation of 3.5 dB cm(-1) MHz(-1) with linear frequency-dependence and an acoustic velocity of 1020 +/- 20 m s(-1). Scattering particles, which are added to the VMM to increase echogenicity and add speckle texture, lead to higher attenuation, depending on particle concentration and frequency. The VMM is stable over time, with a Young's elastic modulus of 1.3 to 1.7 MPa for strains of up to 10%, which mimics human arteries under typical physiological conditions. The phantom is sealed to prevent TMM exposure to air or water, to avoid changes to the acoustic velocity.     

Peroxisome proliferator-activated receptor alpha protects against alcohol-induced liver damage

The mechanisms underlying alcoholic liver disease are not completely understood, but lipid accumulation seems to be central to the cause of this disease. The peroxisome proliferator-activated receptor alpha (PPARalpha) plays an important role in the control of lipid homeostasis, metabolism of bioactive molecules, and modulation of inflammatory responses. To investigate the roles of PPARalpha in alcoholic liver injury, wild-type and PPARalpha-null mice were continuously fed a diet containing 4% ethanol, and liver injury was analyzed. PPARalpha-null mice fed ethanol exhibited marked hepatomegaly, hepatic inflammation, cell toxicity, fibrosis, apoptosis, and mitochondrial swelling. Some of these hepatic abnormalities were consistent with those of patients with alcoholic liver injury and were not found in wild-type mice. Next, the molecular mechanisms of ethanol-induced liver injury in PPARalpha-null mice were investigated, and changes related to ethanol and acetaldehyde metabolism, oxidative stress, inflammation, hepatocyte proliferation, fibrosis, and mitochondrial permeability transition activation occurred specifically in PPARalpha-null mice as compared with wild-type mice. In conclusion, these studies suggest a protective role for PPARalpha in alcoholic liver disease. Humans may be more susceptible to liver toxicity induced by ethanol as PPARalpha expression in human liver is considerably lower compared to that of rodents.