Soy isoflavone extracts stimulate the growth of nude mouse xenografts bearing estrogen-dependent human breast cancer cells (MCF-7).

We explored the effects of different lifetime exposures to soy isoflavone extracts on the growth of estrogen-dependent human breast cancer cells (MCF-7) implanted into athymic mice of different ovarian statuses. The athymic mice, ovariectomized or not, were implanted with MCF-7 cells. Mice were fed with low, moderate and high doses of soy isoflavone extract, at dietary concentrations of 6.25, 12.5 and 25 g/kg, in different reproductive models, respectively. The expression of ki-67 was detected by immunohistochemistry. pS2 expression in tumors was analyzed by real-time PCR. Estrogen level in the serum was measured by chemiluminescence enzyme immunoassay. Total genistein and daidzein levels in serum and urine were determined by liquid chromatography-electrospray tandem mass spectrometry (LC-ES/MS/MS). In Group A, on week 4, nude mice were exposed to different doses of soy iosflavone extracts. In Group B, the experimental diets were given to the nude mice following ovariectomy and tumor implantation. In both groups, 6.25 and 12.5 g/kg soy isoflavone extracts stimulated the growth of MCF-7 xenografts, increased pS2 expression, proliferation and estrogen level in serum. In both Group B (postmenopausal mouse model) and Group C (premenopausal mouse model), soy isoflavone extracts at doses of 6.25 and 12.5 g/kg showed stimulatory effects on the growth of MCF-7 tumors. In conclusion, administration of soy isoflavone extracts at doses of 6.25 and 12.5 g/kg during adolescence or later in life stimulated tumor growth in both menopausal and postmenopausal mouse models.

Reproductive hormones in relation to polycyclic aromatic hydrocarbon (PAH) metabolites among non-occupational exposure of males.

A limited number of studies have suggested that exposure to PAHs may affect reproductive hormones. Subjects (n=642) in this study were from the affiliated hospitals of Nanjing Medical University. Individual exposures to PAHs were measured as spot urinary concentrations of four PAH metabolites, including 1-naphthol (1-N), 2-naphthol (2-N), 2-hydroxyfluorene (2-OF) and 1-hydroxypyrene (1-OP), which were adjusted by urinary creatinine (CR). Blood samples were collected to measure serum levels of reproductive hormones, including follicle-stimulating hormone (FSH), luteotrophic hormone (LH), estradiol (E2), testosterone (T) and prolactin (PRL). All of the subjects had detectable levels of the four metabolites of PAHs in their urine samples. The median concentrations of 1-N, 2-N, 2-OF and 1-OP were 2.440, 4.176, 2.843 and 1.148 microg/g of CR. There were significant P-values between increased CR-adjusted 1-N tertiles and E2 concentration, 2-OF tertiles and LH, FSH level, 1-OP and E2 level. The multivariate linear regression results also showed significant correlation between the levels of serum LH and 1-OP (the adjusting P-value was 0.048), but no correlations were found between other hormones and the level of PAH metabolites. These observed correlations between levels of hydroxy-PAH and some altered hormones indicated slight endocrine effects on adult men with PAH exposure.

Relationship between urinary metabolites of polycyclic aromatic hydrocarbons and thyroid hormone levels in Chinese non-occupational exposure adult males.

Polycyclic aromatic hydrocarbons (PAH) are ubiquitous global pollutants. Limited studies suggested that PAH may interfere with thyroid function in animals, but little is known about humans. A population of 480 Chinese males was recruited. Using LC-MS/MS, four urinary metabolites of PAH including 1-hydroxynaphthalene (1-N), 2-hydroxynaphthalene (2-N), 1-hydroxypyrene (1-P) and 2-hydroxyfluorene (2-F) were measured in spot urinary samples, which were adjusted by urinary creatinine (CR). Blood samples were collected for measuring serum levels of thyroid hormones including total thyroxine (TT4), free triiodothyronine (FT3), free thyroxine (FT4) and thyroid-stimulating hormone (TSH). The median CR-adjusted urine PAH concentrations of 1-N, 2-N, 1-P, 2-F were 2.306, 4.047, 1.155 and 2.899 microg g(-1) of CR, respectively. Significant p-values for trend were found for men with higher 2-F tertiles and were more likely to possess high-reference TSH levels. In addition, the multivariate linear regression models showed significant positive correlations for TSH levels with increased CR-adjusted 2-F concentration. No significant associations were found between other thyroid hormones levels and PAH metabolite concentrations. These results indicated that PAH exposure might be related to altered male thyroid hormone levels, but further study is needed to confirm these observed findings.

Simultaneous determination of phytoestrogens and key metabolites in breast cancer patients' urine by liquid chromatography-tandem mass spectrometry.

A novel, selective and sensitive liquid chromatography-tandem mass spectrometry method has been developed and validated for the simultaneous determination of phytoestrogens and their key metabolites in human urine in this study. This method includes internal standard (IS) screening, analytical sample preparation procedure establishment, and linear range investigation. The analytical sample was extracted by liquid-liquid extraction from urine sample. The phytoestrogens and related key metabolites were separated with Agilent Zorbax Eclipse XDB-C18 chromatographic column using methanol and water as mobile phase. The Quattro premier MICROMASS mass spectrometer in negative ion selected reaction monitoring (SRM) mode using electrospray ionization was applied to detect the phytoestrogens and key metabolites. To validate the developed liquid chromatography-tandem mass spectrometry method, the intra- and inter-day precisions, specificity, sensitivity, reproducibility, and sample detective concentration range were evaluated. This is the first reported phytoestrogens analysis and validation study that demonstrates the feasibility of using liquid chromatography-electrospray ionization mass spectrometry to simultaneously analyze ten analytes including both phytoestrogens and their key metabolites in urine samples collected for epidemiological studies in human.

The relationship of 3-PBA pyrethroids metabolite and male reproductive hormones among non-occupational exposure males.

Many pesticides possess hormonal activities and have been classified as endocrine disrupting chemicals. Synthetic pyrethroids are one kind of the most common pesticides used in the world. In the present study, we explored the association between serum reproductive hormone levels and urinary creatine (CR) adjusted concentration of 3-phenoxybenzoic acid (3-PBA), a general metabolite of pyrethroids, in Chinese adult men. The study subjects (n=212) were from the affiliated hospitals of Nanjing Medical University. By using GC-MS, urinary 3-PBA level of each subject was measured and adjusted by urinary CR. Blood samples were collected for measuring the serum levels of reproductive hormones, including follicle stimulating hormone (FSH), luteinizing hormone (LH), estradiol (E2), testosterone (T) and prolactin (PRL). All the subjects had detectable levels of 3-PBA in their urine samples. The median concentration of 3-PBA was 0.815 microg g (-1)of CR. The results showed that there was positive associations between the levels of serum LH and 3-PBA (p=0.013) but negative associations between E2 and 3-PBA level (p=0.022), and the adjusting p-value was 0.044 for LH and E2, which suggested that pyrethroids are capable of disrupting the male endocrine function. In adult men, urinary 3-PBA levels were associated with increased LH and reduced E2 levels. On a population level, these reductions show potential public health importance because of widespread exposure to these pesticides.

The relation between urinary metabolite of pyrethroid insecticides and semen quality in humans.

OBJECTIVE: To explore the possible association between internal exposure levels of 3-phenoxybenzoic acid (3-PBA), an urinary metabolite of pyrethroids, and altered semen quality in Chinese men. DESIGN: A retrospective case-control study. SETTING: Center of clinical reproductive medicine. PATIENT(S): Three hundred seventy-six men with nonobstructive infertility. MAIN OUTCOME MEASURE(S): Urinary 3-PBA concentration, semen volume, sperm concentration, sperm number per ejaculum, sperm motility, sperm progression, and motion parameters. RESULT(S): The median 3-PBA concentration was 0.879 microg/g of creatinine. There was suggestive association between increased creatinine-adjusted 3-PBA quartiles and sperm concentration (odd ratios for the first, second, third, and fourth quartiles were 1.00, 1.31, 1.73, and 2.04, respectively), whereas sperm volume, sperm number per ejaculum, and sperm motility were weakly or nonsignificantly associated with 3-PBA quartiles. The sperm progression and motion parameters associated with creatinine-adjusted 3-PBA levels were straight line velocity (VSL) and curvilinear velocity (VCL). CONCLUSION(S): These observed associations between 3-PBA levels and some altered semen quality indicated the reproductive effects of pyrethroid exposure on adult men.

Preventive effects of quercetin against benzo[a]pyrene-induced DNA damages and pulmonary precancerous pathologic changes in mice.

The aim of this study was to investigate the preventive effects of quercetin against benzo[a]pyrene-induced blood lymphocyte DNA damages and pulmonary precancerous pathologic changes in mice, and to reveal the potential mechanism behind these effects. In this study, mice in quercetin-treated groups were given quercetin for 90 days. After one week of treatment, mice in the quercetin-treated groups and the positive control group received a single intraperitoneal dose of benzo[a]pyrene (100 mg/kg body weight). The results of single cell gel electrophoresis assay showed that the average lengths of the comet cell tail and DNA damage in the peripheral blood lymphocytes of mice induced by benzo[a]pyrene decreased significantly as a result of quercetin treatment dose-dependently. Light microscopic examination showed that the degrees of pulmonary precancerous pathologic changes in the quercetin-treated groups decreased significantly compared with those in the positive control group. Meanwhile, the cytochrome P4501A1-linked 7-ethoxyresorufin O-dealkylase activities in lung microsomes of mice decreased as the dose of quercetin increased. The results of this in vivo study revealed that quercetin had a significant preventive effect on benzo[a]pyrene-induced DNA damage, and had a potential chemopreventive effect on the carcinogenesis of lung cancer induced by benzo[a]pyrene. The mechanism of these effects of quercetin could be related to the inhibition of cytochrome P4501A1 activity.

[Determination of quercetin in apples by reversed-phase high performance liquid chromatography].

A method for the determination of quercetin in pulp and peel of apples by reversed-phase high performance liquid chromatography with internal standard was developed. Samples were frozen at -80 degrees C for 24 h, then added 6 mol/L hydrochloride under the protection of antioxidant 2,6-di-tert-butyl-p-cresol. The slurry was hydrolyzed thermostatically at 90 degrees C for 2 h and centrifugated for 10 min. The separation was performed on an ODS column (150 mm x 6.0 mm i.d., 5 microm). Methanol-water (55:45, v/v) (pH adjusted to 3.3 with acetic acid) was used as the mobile phase with a flow rate of 1.0 mL/min. The injection volume was 20 microL. The detection wavelength was 370 nm. The results showed that the quercetin content in pulp and in peel were 3.11-10.78 microg/g and 253.57-744.59 microg/g, respectively. The mean recovery of quercetin in apple pulp was 100.4%. The method is simple, accurate, and reliable.

[Effects of exposure to aluminum on some metal elements contents in hippocampus of rat].

OBJECTIVE: To investigate the effects of exposure to aluminum (Al) on Zn, Fe, Cu and Ca contents in hippocampus of rats. METHODS: AlCl(3).6H(2)O was administered orally through diet (8% of body weight) to SD rats at doses of 0 (A), 11.2 (B), 55.9 (C), 111.9 (D) mg Al(3+)/kg BW for successive 90 days. Then Al, Zn, Fe, Cu and Ca contents in hippocampi of rats were determined by atomic absorption spectrophotometry. RESULTS: After oral exposure to Al, the Al content in hippocampus of rat increased significantly with a remarkable dose-effect relationship (r = 0.731, P < 0.001), The Zn, Fe, Ca and Cu contents in these four groups are as follows: Group A (18.29 +/- 2.48, 24.86 +/- 1.97, 48.69 +/- 22.08, 4.53 +/- 0.99) mg/g, Group B (17.22 +/- 2.06, 27.54 +/- 2.87, 42.79 +/- 14.42, 4.06 +/- 0.41) mg/g, Group C (14.46 +/- 1.90, 20.18 +/- 2.79, 29.95 +/- 7.33, 3.98 +/- 0.25) mg/g, Group D (15.85 +/- 2.54, 20.96 +/- 2.83, 36.14 +/- 12.66, 4.53 +/- 0.58) mg/g. Compared with the control group A, the Zn and Fe contents in group B and group C decreased significantly (P < 0.05), and the Ca content in group C also decreased significantly. CONCLUSION: Oral exposure to Al may result in accumulation of Al in hippocampus of brain and thus affect some essential elements (Zn, Fe, Cu and Ca) contents in the hippocampus at different degrees.