Combined Effects of Exposure to Noise and Vibration on Human Postural Equilibrium under Simulated Driving Conditions

There is little information about drivers’body balance responses to combined exposure of noise and vibration.To fill the gap,this study aims to investigate the combined effects of exposure to noise and whole-body vibration(WBV)on the body balance under simulated driving conditions.For this purpose,30 male participants were exposed to noise level at 85 dB(A)and two vibration levels(0.87 and 1.3 m/s^(2))in five sessions.The design of the study was repeated-measures,and it attempted to assess the effects of 40 minutes of exposure to noise and/or WBV.Moreover,the participants’fatigue was measured with the Borg scale(CR 10).The findings revealed there was a significant change in body sway after WBV and combined noise and WBV exposure(p<0.05).However,no significant difference was found in exposure to noise alone(p>0.05).The effect sizes of exposure to noise,WBV(1.3 m/s^(2)),and combined noise and WBV(1.3 m/s^(2))on body balance were 0.035,0.425,and 0.635,respectively.Also,single exposure to WBV caused more fatigue than single exposure to noise(p<0.05).Combined noise and WBV exposure descriptively caused more fatigue in comparison with the influence of WBV alone.The study concluded that the combined effects of exposure to noise and vibration are more than the sum of them.So,some synergistic effects may be observed in human body balance.It is essential to increase drivers’awareness and revise current health care interventions about new possible effects of combined exposures.

Mediating Role of Glucose-Lipid Metabolism in the Association between the Increased Risk of Coronary Heart Disease and Exposure to Organophosphate Esters,Phthalates,and Polycyclic Aromatic Hydrocarbons

There is a lack of human evidence concerning the cardiovascular effects of combined exposure to endocrine disruptors.This case-control study sought to investigate coronary heart disease(CHD)associations with exposure to organophosphate flame retardants(OFRs),phthalates(PAEs),and polycyclic aromatic hydrocarbons(PAHs)among 148 adults with coronary-angiography-diagnosed CHD and 320 healthy adults from southern China.The mediating role of glucose-lipid metabolism was also explored.Bayesian kernel machine regression suggested that when exposure status was fixed to the 75th percentile with the median value as the reference,exposure to OFRs,PAEs,and PAHs was associated with an 84%(95%CI:36%−134%),132%(12%−252%),and 214%(89%−331%)increased risk of developing CHD,respectively.Weighted quantile sum regression indicated urinary bis(2-butoxyethyl)phosphate(BBOEP),dibutyl phosphate(DBP),monoisononyl phthalate(miNP),and metabolites of phenanthrene may be major contributors to the overall effect of mixtures.In further analyses on identified chemical risk factors,mediation analyses suggested exposure to phenanthrene may increase the risk of CHD via elevating total cholesterol and blood glucose,while exposure to DiNP mainly associates with serum lipids.Besides,we observed a slight mediation effect of oxidative DNA damage between urinary BBOEP and risk of CHD.These results provide potential direction for further experimental studies.Longitudinal evidence is needed to clarify the causation of the results.

Combined effects of fluoride and arsenic exposure on proliferation,differentiation and beta-catenin expression in rat osteoblasts

<正>Objective To investigate the combined effects of fluoride(Na F)and arsenate(Na As O2)exposure on proliferation,differentiation and bata-catenin expression in SD rat osteoblasts.Methods Osteoblasts were isolated from calvarias of twelve SD rats born in 1~3 days and cul-

Enhanced hepatotoxicity induced by repeated exposure to polychlorinated biphenyls and 2,3,7,8-tetrachlorodibenzo-p-dioxin in combination in male rats

2,3,7,8-Tetrachlorodibenzo-p-dioxin （TCDD） and polychlorinated biphenyls （PCBs） are among persistent polyhalogenated aromatic hydrocarbons that exist as complex mixtures in the environment worldwide. The present study was attempted to investigate the hepatotoxicity following repeated exposure to TCDD and PCBs in combination in male rats, and to reveal the involvement of potential mechanisms. Male Sprague-Dawley rats were exposed to TCDD （10 Ixg/kg） and Aroclor 1254 （10 mg/kg, a representative mixture of PCBs） alone or in combination by intragastric administration. After 12-day exposure, all treatments produced significant hepatotoxicity as characterized by changes of plasma biochemistry and histopathological changes. These effects were more prominent in the combined group. Furthermore, all treatments induced hepatic cytochrome P450 1A1 （CYP1A1） expression, and the maximal level of CYP1A1 expression was observed in the combined group, as in the case of the most severe hepatotoxicity evoked by the combined exposure. These findings indicated that the hepatotoxicity induced by TCDD and Aroclor 1254 might be ascribed to the high expression of hepatic CYP1A1. The present study demonstrates the enhanced hepatotoxicity after exposure to TCDD and PCBs in combination in rats.

Hypoxic and temporal variation in the endocrine disrupting toxicity of perfluorobutanesulfonate in marine medaka(Oryzias melastigma)

Perfluorobutanesulfonate(PFBS)is an emerging pollutant capable of potently disrupting the sex and thyroid endocrine systems of teleosts.However,the hypoxic and temporal variation in PFBS endocrine disrupting toxicity remain largely unknown.In the present study,adult marine medaka were exposed to environmentally realistic concentrations of PFBS(0 and 10μg/L)under normoxia or hypoxia conditions for 7 days,aiming to explore the interactive behavior between PFBS and hypoxia.In addition,PFBS singular exposure was extended till 21days under normoxia to elucidate the time-course progression in PFBS toxicity.The results showed that hypoxia inhibited the growth and caused the suspension of egg spawn regardless of PFBS exposure.With regard to the sex endocrine system,7-day PFBS exposure led to an acute stimulation of transcriptional profiles in females,which,subsequently,recovered after the 21-day exposure.The potency of hypoxia to disturb the sex hormones was much stronger than PFBS.A remarkable increase in estradiol concentration was noted in medaka blood after hypoxia exposure.Changes in sex endocrinology of coexposed fish were largely determined by hypoxia,which drove the formation of an estrogenic environment.PFBS further enhanced the endocrine disrupting effects of hypoxia.However,the hepatic synthesis of vitellogenin and choriogenin,two commonly used sensitive biomarkers of estrogenic activity,failed to initiate in response to the estrogen stimulus.Compared to sex endocrine system,disturbances in thyroidal axis by PFBS or hypoxia were relatively mild.Overall,the present findings will advance our toxicological understanding about PFBS pollutant under the interference of hypoxia.

Leaf metabolic influence of glyphosate and nanotubes on the Arabidopsis thaliana phyllosphere

Chemical exposure can indirectly affect leaf microbiota communities,but the mechanism driving this phenomenon remains largely unknown.Results revealed that the co-exposure of glyphosate and multi-carbon nanotubes(CNTs)caused a synergistic inhibitory effect on the growth and metabolism of Arabidopsis thaliana shoots.However,only a slight inhibitory effect was induced by nanotubes or glyphosate alone at the tested concentrations.Several intermediate metabolites of nitrogen metabolism and fatty acid synthesis pathways were upregulated under the combined treatment,which increased the amount of energy required to alleviate the disruption caused by the combined treatment.Additionally,compared with the two individual treatments,the glyphosate/nanotube combination treatment induced greater fluctuations in the phyllosphere bacterial community members with low abundance(relative abundance(RA)<1%)at both the family and genus levels,and among these bacteria some plant growth promotion and nutrient supplement related bacteria were markable increased.Strikingly,strong correlations between phyllosphere bacterial diversity and metabolites suggested a potential role of leaf metabolism,particularly nitrogen and carbohydrate metabolism,in restricting the range of leaf microbial taxa.These correlations between phyllosphere bacterial diversity and leaf metabolism will improve our understanding of plant-microbe interactions and the extent of their drivers of variation and the underlying causes of variability in bacterial community composition.