Prenatal phthalate exposure and placental size and shape at birth: A birth cohort study.

OBJECTIVE: There is concern over the potential placental effects of prenatal phthalate exposure, and the potential adverse effects of prenatal phthalate exposure require further study; however, few data are available in humans. We investigated the associations between phthalate exposure in each trimester and both placental size and shape at birth. METHODS: We measured the urinary concentrations of phthalate metabolites among 2725 pregnant women in the Ma'anshan Birth Cohort. Before collecting urine samples from each of the three trimesters, the pregnant women were interviewed via questionnaires. Placental information was obtained from hospital records. We estimated the sex-specific associations between urinary phthalate concentrations in each trimester and both placental size and shape at birth using adjusted multiple regression. A linear mixed model was used for the repeated measures analysis with subject-specific random intercepts and slopes for gestational age at sample collection to test the effect of phthalate levels on placental size and shape and to estimate the effect sizes. RESULTS: Overall, placental breadth increased by 0.148cm (95% CI: 0.078, 0.218) with each 1 ln-concentration increase in MBP in the first trimester. The difference between placental length and breadth (length-breadth) decreased by 0.086cm (95% CI: -0.159, -0.012) and 0.149cm (95% CI: -0.221, -0.076) with each 1 ln-concentration increase in MMP and MBP, respectively, in the first trimester. In the second trimester, placental thickness increased by 0.017cm (95% CI: 0.006, 0.027), 0.020cm (95% CI: 0.004, 0.036), 0.028cm (95% CI: 0.007, 0.048), and 0.035cm (95% CI: 0.018, 0.053) with each 1 ln-concentration increase in MMP, MBP, MEOHP, and MEHHP, respectively. In the third trimester, placental thickness increased by 0.037cm (95% CI: 0.019, 0.056) and 0.019cm (95% CI: 0, 0.037) with each 1 ln-concentration increase in MBP and MEHP, respectively. Multiple linear regression for each offspring sex indicated that prenatal phthalate exposure increased placental thickness in both the first and second trimesters in males, whereas the corresponding relationship was close to null in females. Linear mixed models (LMMs) yielded similar results. CONCLUSION: Our results suggest the presence of associations between prenatal phthalate exposure and placental size and shape. Exposure to certain phthalates may cause the placenta to become thicker and more circular. Associations appeared stronger for the subsample representing male offspring than those for the subsample representing female offspring. Given the few studies on this topic, additional research is warranted.

Season-dependent concentrations of urinary phthalate metabolites among Chinese pregnant women: Repeated measures analysis.

In utero exposure to phthalates may have adverse effects on pregnant women and their offsprings. Therefore, the exposure level of these substances among individuals, particularly among sensitive population, is of concern. The objective of the present study is to characterize urinary concentrations of phthalate metabolites at multiple time points during pregnancy in Chinese women. A total of 3455 pregnant women were included from Ma'anshan Birth Cohort in China. Spot urine samples in the morning (8:00-10:00) and questionnaires were obtained at three separate visits (approximately in 10, 26, and 34 gestational weeks). Seven phthalate metabolites from urine samples were analyzed, including monomethyl phthalate (MMP), monoethyl phthalate (MEP), monobutyl phthalate (MBP), mono benzyl phthalate (MBzP), mono-2-ethylhexyl phthalate (MEHP), mono (2-ethyl-5-oxohexyl) phthalate (MEOHP) and mono (2-ethyl-5-hydroxyhexyl) phthalate (MEHHP). Geometric means of concentrations were ranged from 0.05 to 41.0ng/mL for all the metabolites mentioned above. No individual exposure level was above the 95th percentiles for all the seven phthalates. On the three separate visits, 0.5%, 0.9% and 1.2% of the participants had coexposure to above the 75th percentiles for all metabolites. Taken these visits together, a total of 29 urine samples had concentrations above the 95th percentiles, while 3.0%-5.6% of urine levels were above 75th percentiles for at least one specific phthalate metabolite. We observed moderate intraclass correlation coefficients (ICCs) ranging from 0.44 to 0.56 for MBzP, MEHP and MEP, and lower ICCs, from 0.28 to 0.32, for MMP, MBP, MEOHP and MEHHP. Sampling season was associated with concentrations of all phthalate metabolites, showing heavier exposure was more likely to occur during summer. In summary, phthalate exposure is prevalent in Chinese pregnant women. However, throughout pregnancy coexposure to multiple phthalates at the upper percentile of exposure is infrequent. Mild to moderate temporal stability indicates that a single measurement in spot urine collected in the morning (8:00-10:00) seems not enough to describe throughout pregnancy phthalate exposure. Urinary levels vary by sampling seasons, which should be taken into consideration in future analyses.

Cumulative risk assessment of phthalates associated with birth outcomes in pregnant Chinese women: A prospective cohort study.

A prospective cohort study of a Chinese population of mother-neonate pairs (n = 3103) was conducted to investigate the relationship between the cumulative hazard index (HI) of combined diethyl phthalate (DEP), dibutyl phthalate (DBP), dibenzyl phthalate (BBzP) and di(2-ethylhexyl) phthalate (DEHP) exposure and birth outcomes. The estimated HI for phthalates was based on phthalate metabolite concentrations in urine collected between 5th and 14th gestational weeks. The median HI values according to the European Food Safety Authority tolerable daily intake (HITDI) and U.S. Environmental Protection Agency reference dose (HIRfD) were 0.358 and 0.187, respectively. A total of 16.3% and 1.9% of the women exhibited HITDI and HIRfD exceeding the value of one, respectively. In unadjusted models, the categories (low < P25, median P25-P50, high > P75) of HITDI were associated with decreased birth weight (ß = -26.34 g, p = 0.021) and head circumference (ß = -0.09 cm, p = 0.029), whereas those for HIRfD were negatively associated with birth weight (ß = -31.74 g, p = 0.005), birth length (ß = -0.11 cm, p = 0.032), head circumference (ß = -0.13 cm, p = 0.003) and chest circumference (ß = -0.10 cm, p = 0.021) in all neonates. Adjustment for potential confounders revealed that HIRfD was inversely associated with head circumference (ß = -0.10 cm, p = 0.020). Stratification by gender indicated that HIRfD was associated with decreased birth length (ß = -0.17 cm, p = 0.041) in infant boys and HITDI was associated with decreased birth weight (ß = -33.12 g, p = 0.036) and head circumference (ß = -0.13 cm, p = 0.027) in girls. This is the first study on the cumulative risk assessment of phthalate exposures in pregnant Chinese women. We found that the HI values of multiple phthalate co-exposure were sex-specifically related to birth outcomes.

Maternal phthalate exposure during the first trimester and serum thyroid hormones in pregnant women and their newborns.

Animal and human studies have suggested that phthalate alters thyroid hormone concentrations. This study investigated the associations between phthalate exposure during the first trimester and thyroid hormones in pregnant women and their newborns. Pregnant women were enrolled from the prospective Ma'anshan Birth Cohort study in China. A standard questionnaire was completed by the women at the first antenatal visit. Seven phthalate metabolites were measured in one-spot urine at enrolment (10.0 ± 2.1 gestational weeks), as were thyroid hormone levels in maternal and cord sera. Multivariable linear regression showed that 1-standard deviation (SD) increase in natural log (ln)-transformed mono(2-ethylhexyl) phthalate (MEHP) and mono(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP) was associated with 0.163 µg/dL (p = 0.001) and 0.173 µg/dL (p = 0.001) decreases in maternal total thyroxine (TT4). Both MEHP and MEHHP were negatively associated with maternal free thyroxine (FT4; ß: -0.013, p < 0.001 and ß: -0.011, p = 0.001, respectively) and positively associated with maternal thyroid-stimulating hormone (ß: 0.101, p < 0.001; ß: 0.132, p < 0.001, respectively). An inverse association was observed between monobenzyl phthalate and maternal TT4 and FT4. A 1-SD increase in ln-transformed monoethyl phthalate was inversely associated with maternal TT4 (ß: -0.151, p = 0.002). By contrast, the concentrations of phthalate metabolites in urine were not associated with those of thyroid hormone in cord serum. Our analysis suggested that phthalate exposure during the first trimester disrupts maternal thyroid hormone levels.

[Spectrometric study on the effect of denaturant on the conformation of tartary buckwheat protein].

The effect of ethanol and GuHCl solution on the structure of tartary buckwheat protein (TBWSP31) was studied by UV differential absorption and fluorescence emission spectra. The alcohol denaturation of TBWSP31 was a kind of partial denaturation. The hydrophobic core of TBWSP31 remained intact and the conformation of the hydrophilic shell was changed. When TBWSP31 was denatured by GuHCl solution with higher concentration, Tyr and Trp residues were exposed to the polar aqueous solvents from the hydrophobic core, and the microenvironment showed a great change.

Effect of Vaccinium bracteatum Thunb. leaves extract on blood glucose and plasma lipid levels in streptozotocin-induced diabetic mice.

AIM OF THE STUDY: To investigate the hypoglycemic effects of Vaccinium bracteatum Thunb. leaves (VBTL) extract in streptozotocin-induced diabetic mice. MATERIALS AND METHODS: After administration of VBTL extract for 4 weeks, the body weight, organ weight, blood glucose (BG), insulin and plasma lipid levels of streptozotocin-induced diabetic mice were measured. RESULTS: Body weights of diabetic mice treated with VBTL extract were partly recovered. The BG levels of AEG (diabetic mice treated with VBTL aqueous extract) were reduced to 91.52 and 85.82% at week 2 and week 4, respectively (P<0.05), while those of EEG (diabetic mice treated with VBTL ethanolic extract) were reduced slightly (P>0.05). The insulin levels of AEG and EEG were obviously higher (P<0.05) than those of MC (diabetic mice in model control group). Comparing with MC, AEG and EEG had significantly lower (P<0.05) TC or TG levels and similar HDL-cholesterol or LDL-cholesterol levels. In comparison with non-diabetic control mice, AEG had similar plasma lipid levels except higher LDL-cholesterol level, while EEG had higher TC, TG and LDL-cholesterol levels and lower HDL-cholesterol levels. CONCLUSIONS: Both aqueous and ethanolic extract of VBTL possess a potential hypoglycemic effect in streptozotocin-induced diabetic mice.

[The secondary structure of winter-wheat-bran antifreeze protein determined by FTIR and CD spectrum].

The secondary structure of winter wheat bran antifreeze protein was analyzed by FTIR and CD spectra. The characteristic peaks of the secondary structure of the winter wheat bran antifreeze protein were overlapped from the FTIR analysis. The overlapped peaks of amide I and III of the winter wheat bran antifreeze protein were fitted by the Gauss peak to show the characteristic peaks of the alpha-helix, beta-sheet, beta-turn and random coil. The CD spectrum was evaluated by the Chen-Yang principle and analyzed by the least squares method. Furthermore, the difference between the two analyses was discussed. The final results showed that the alpha-helix, beta-sheet, beta-turn and random coil of the winter wheat bran antifreeze protein was 15.05%-15.87%, 36.00%-36.92%, 17.31%-17.75%, and 30.303-30.82%, respectively. The result would be helpful to the study of the antifreeze mechanism of the winter wheat bran antifreeze protein.

Improvement of texture properties and flavor of frozen dough by carrot (Daucus carota) antifreeze protein supplementation.

The effects of concentrated carrot protein (CCP) containing 15.4% (w/w) carrot (Daucus carota) antifreeze protein on texture properties of frozen dough and volatile compounds of crumb were studied. CCP supplementation lowered the freezable water content of the dough, resulting in some beneficial effects including holding loaf volume steadily and making the dough softer and steadier during frozen storage. Furthermore, SPME-GC-MS analysis showed CCP supplementation did not give any negative influences on volatile compounds of crumb and gave a pleasant aroma felt like Michelia alba DC from trans-caryophyllene simultaneously. Combining our previous results that CCP supplementation improves the fermentation capacity of the frozen dough, CCP could be used as a beneficial additive for frozen dough processing.

Accumulation of gamma-aminobutyric acid in rice germ using protease.

The accumulation of gamma-aminobutyric acid (GABA) in the rice germ by using protease was investigated. After the proteolytic hydrolysis of germ protein by trypsin, the amount of GABA reached about 2.26 g per 100 g of germ. This demonstrates that the GABA yield could be significantly increased by protease. Our method is efficient and safe for manufacturing health food enriched with GABA.

Determination of 266 pesticide residues in apple juice by matrix solid-phase dispersion and gas chromatography-mass selective detection.

A macro matrix solid-phase dispersion (MSPD) method was developed to extract 266 pesticides from apple juice samples prior to gas chromatography-mass selective detection (GC-MSD) determination. A 10 g samples was mixed with 20 g diatomaceous earth. The mixture was transferred into a glass column. Pesticide residues were leached with a 160 mL hexane-dichloromethane (1:1) at 5 mL/min. Two hundred and sixty-six pesticides were divided into three groups and detected by GC-MSD under selective ion monitoring. The proposed method takes advantage of both liquid-liquid extraction and conventional MSPD methods. Application was illustrated by the analysis of 236 apple juice samples produced in Shaanxi province China mainland this year.