Toxic Effects of Tetrabromobisphenol A on Thyroid Hormones in SD Rats and the Derived-reference Dose / 生物医学与环境科学（英文）

The present study determined the thyroid hormone interference of tetrabromobisphenol A (TBBPA) in Sprague-Dawley (SD) rats, and the derived-reference dose (RfD) of different endpoint effects on mammals based on experimental results and data collection. Based on repeated exposure toxicity tests on mammals and extensive research, the present study used BMDS240 Software to derive a benchmark dose, and analyzed the accuracy and uncertainty, and similarity with other studies. Test results on triiodothyronine (T3), thyroxine (T4), and thyroid stimulating hormone (TSH) demonstrated that all the indicators presented a non-monotonous dose-effect relationship clearly, except TSH in male rats exposed to 0-1000 mg/kg BW per day. Therefore, RfDs were derived from different critical effects. In summary, RfD for mammals in the present study was found to be 0.6 mg/kg per day.

Effects of polybrominated diphenyl ether-153 lactation exposure on the concentrations of intracellular calcium ion and calcium-activated related enzymes levels of adult rats' cerebral cortex / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the effects of polybrominated diphenyl ether-153 (BDE-153) exposure during lactation period on the calcium ion (Ca(2+)) concentration and calcium-activated enzyme levels in cerebral cortical cells among adult rats and to provide a scientific basis for the study on the developmental neurotoxicity of BDE-153.</p><p><b>METHODS</b>Forty newborn male rats were randomly and equally divided into four groups according to their body weights and litters: 1, 5, and 10 mg/kg BDE-153 groups and olive oil solvent control group. On postnatal day 10 (PND 10), the BDE-153 groups were administrated BDE-153 (0.1 ml/10 g body weight) by intraperitoneal injection, while the olive oil solvent control group was given an equal volume of olive oil. Two months later, these rats were decapitated, and the cerebral cortex was separated quickly on an ice-cold dish. The Ca(2+) concentration in cerebral cortical cells was measured by flow cytometry. The activities of calcineurin (CaN) and Ca(2+)-Mg(2+)-ATP enzyme were determined by colorimetric method. The mRNA and protein expression of calpain-1 and calpain-2 was measured by real-time quantitative PCR and Western blot.</p><p><b>RESULTS</b>The mean fluorescence intensities of intracellular Ca(2+) in control group and 1, 5, and 10 mg/kg BDE-153 groups were 10.83, 1.48, 1.93, and 0.62, respectively; the 1, 5, and 10 mg/kg BDE-153 groups had significantly lower intercellular Ca(2+) concentrations than the control group (P < 0.05). The activities of CaN and Ca(2+)-Mg(2+)-ATP enzyme and mRNA and protein expression of calpain-1 showed no significant differences between the 1, 5, and 10 mg/kg BDE-153 groups and control group (P > 0.05). The protein expression of calpain-2 increased as the dose of BDE-153 rose. Compared with the control group (mRNA: 0.81±0.26; protein: 0.15±0.07), the 5 and 10 mg/kg BDE-153 groups had significantly higher mRNA expression of calpain-2 (5 mg/kg BDE-153 group: 1.16±0.52; 10 mg/kg BDE-153 group: 1.32±0.23) and significantly higher protein expression of calpain-2 (5 mg/kg BDE-153 group: 0.31±0.07; 10 mg/kg BDE-153 group: 0.37±0.06) (P < 0.05). The 10 mg/kg BDE-153 group had significantly higher protein expression of calpain-2 than the 1 mg/kg BDE-153 group (0.37±0.06 vs 0.22±0.07, P < 0.05).</p><p><b>CONCLUSION</b>Ca(2+-) mediated calpain-2 activation may be one of the main mechanisms of BDE-153 neurotoxicity.</p>

Endocrine Disrupting Chemicals and Pubertal Development

During the past decades, advancement in pubertal onset especially in girls has been noticed worldwide. Genetic factors and increasing prevalence of adiposity may contribute, however ubiquitous presence of endocrine disrupting chemicals (EDCs) is suspected to be involved in the trend of earlier pubertal onset. Most of known EDCs have estrogenic and/or anti-androgenic actions and few have androgenic or anti-estrogenic effects. Some studies reported earlier age at menarche after exposure to polycholorinated biphenyls (PCBs), polybrominated biphenyls, dicholordiphenyltrichloroethane, phthalate esters, while several other studies found no effect of these compounds on Tanner stages or age at menarche in girls. Limited studies reported an association of delayed puberty in boys and exposure to PCBs or the pesticide endosulfan. However, epidemiological research on the effects of EDCs on sexual maturation is hampered by many pitfalls, such as the mixture of many chemicals with different effects in environment, unidentified critical window of exposure, and limited knowledge about the time lag between exposure and effect. In this paper, we reviewed possible mode of actions of different chemical compounds, and summarized animal/human studies shown the effects of EDCs on the pubertal development.

Concentration of polybrominated diphenyl ethers in umbilical cord serum and the influence on newborns birth outcomes in Shanghai / 中华预防医学杂志

<p><b>OBJECTIVE</b>To explore the concentration of polybrominated diphenyl ethers (PBDEs) in umbilical cord serum and analyze the influence of exposure to PBDEs during fetal stage on newborn birth outcomes in Shanghai.</p><p><b>METHODS</b>Fifty delivery women in a Shanghai hospital were surveyed by questionnaire, and the umbilical cord serum were collected from September 2006 to April 2007. All the delivery women were singleton pregnancies, excluding high blood pressure, diabetes, HIV infection and adverse medical history. Seven congeners (BDE-28, BDE-47, BDE-99, BDE-100, BDE-153, BDE-154 and BDE-183) were measured by gas chromatography-negative chemical ionization-mass spectrometry and the influencing factors were analyzed.</p><p><b>RESULTS</b>Newborns' length, weight, chest circumference, head circumference and body mass index (BMI) were (50.15 ± 0.75) cm, (3.49 ± 0.42) kg, (34.76 ± 1.51) cm, (35.03 ± 1.40) cm, (13.76 ± 1.36) kg/m(2), respectively. The median of Σ(7PBDEs) concentration in umbilical cord serum was 14.06 (1.03 - 379.73) ng/g lipid weight (lw). The detection rate of BDE-28, BDE-47, BDE-99, BDE-100, BDE-153, BDE-154 and BDE-183 were 22% (11/50), 22% (11/50), 98% (49/50), 72% (36/50), 76% (38/50), 90% (45/50) and 14% (7/50), respectively. The median (range) of PBDEs (BDE-28, BDE-47, BDE-99, BDE-100, BDE-153, BDE-154, BDE-183) congeners were < LOD (< LOD-137.20 ng/g lw), < LOD (< LOD-33.17 ng/g lw), 7.54 ng/g lw (< LOD-94.01 ng/g lw), 1.57 ng/g lw (< LOD-46.95 ng/g lw), 0.63 ng/g lw (< LOD-79.08 ng/g lw), 0.63 ng/g lw (< LOD-22.30 ng/g lw) and < LOD (< LOD-21.63 ng/g lw), respectively. The newborns' BMI showed a negative correlation with BDE-99 (r = -0.347, P < 0.05) and BDE-154 (r = -0.292, P < 0.05). BDE-99 in low-length group (≤ 50 cm, 10.59 ng/g lw) was significantly higher (t = 2.32, P = 0.03) than that in high-length group (> 50 cm, 3.60 ng/g lw).</p><p><b>CONCLUSION</b>PBDEs were commonly detected in newborns' umbilical cord serum in this study. Our findings indicated that exposure to PBDEs adversely affected the development of the newborns.</p>

[Degradation of transformer oils by photolysis in order to reduce occupational and environmental hazards]

Polychlorinated biphenyls [PCBs] are toxic, persistent, bio-accumulate and pose a risk of causing adverse effects on human health and to the environment. PCB compounds exert varios impacts on human depending upon age, route of entry, intensity and frequency of exposure. This study was conducted to determine the effect of UV-C, hydrogen peroxide and solvent on the photodegradation of PCBs. The photochemical reactor was of annular geometry [500 ml volume] with a cylindrical low-pressure mercury lamp emitting at 254 nm. The power emitted by the lamp was 6 W. The whole lamp was immersed into a reactor with temperature of 32 +/- 2 C. The PCBs were analyzed by GC/ECD equipment. The degradation of total PCBs in terms of one, two and three lamps was 77.5%, 82.9% and 85.2% respectively. The degradation of total PCBs in terms of not using of H[2]O[2] and using 10% and 20% of H[2]O[2] were 74.5%, 79% and 94.5% respectively. The results of this experiments showed that UVC-photolysis of H[2]O[2] leads to a degradation efficiency of PCBs only in the presence of ethanol

Transient and spatial modeling and simulation of polybrominated diphenyl ethers reaction and transport in air, water and soil

The release of the wastes containing polybrominated diphenyl ethers into the environment is a worldwide major concern. Investigation of spatial and temporal variations of polybrominated diphenyl ethers concentrations due to different factors, especially the transport of these species between air and water as well as between air and soil is the purpose of present research. A model was developed and solved using the methods of finite difference and lines. Simulations were implemented for three dimensions of width, length, and height and also time for the air compartment, whereas for the soil and water compartments, variations were considered only with respect to height and time. Transport between water and soil was disregarded for simplicity at this stage. Vancouver's landfill was considered as a case study. Lower concentrations in air and higher concentrations in water at the interface show that these pollutants tend to diffuse from air to water. Concentrations of all four pollutants decrease near the interface in soil as time passes, but they are predicted to be almost constant at other levels

Impact of PBDE-209 exposure during pregnancy and lactation on immune function of offspring rats / 南方医科大学学报

<p><b>OBJECTIVE</b>To assess the potential hazard of environmental deca-brominated diphenyl ether (PBDE-209) exposure to the immune function of the offspring rats.</p><p><b>METHODS</b>The parental Wistar rats were exposed to PBDE-209 administered intragastrically during pregnancy and lactation, and the development of the immune organs and changes in T lymphocyte subset and their proliferation, NK cell surface markers CD161 and serum immunoglobulins (IgM and IgG) were observed.</p><p><b>RESULTS</b>Significant differences in the weight of the immune organs were noted between the exposure group and control group. In the exposure group, the percentage of T lymphocyte subset CD3(+), CD4(+), CD8(+), CD4(+)CD8(+), the percentage of NK cell surface markers CD16 1 and CD4(+)/CD8(+) ratio were lowered, while the percentage of CD4(-)CD8(-) cells increased. T lymphocyte subset proliferation in the exposure group did not show obviously changes, but compared with the control group, the IgM level in the exposure group was significantly lowered. No significant differences were observed in IgG levels between the exposure and control groups.</p><p><b>CONCLUSION</b>Continuous exposure to high-dose PBDE-209 in female rats during pregnancy and lactation results in possible adverse effect on the immune function of the offspring rats.</p>