Covalent adduct formation of histone with organophosphorus pesticides in vitro.

It is established that organophosphorus pesticide (OPP) toxicity results from modification of amino acids in active sites of target proteins. OPPs can also modify unrelated target proteins such as histones and such covalent histone modifications can alter DNA-binding properties and lead to aberrant gene expression. In the present study, we report on non-enzymatic covalent modifications of calf thymus histones adducted to selected OPPs and organophosphate flame retardants (OPFRs) in vitro using a bottom-up proteomics method approach. Histones were not found to form detectable adducts with the two tested OPFRs but were avidly modified by a few of the seven OPPs that were tested in vitro. Dimethyl phosphate (or diethyl phosphate) adducts were identified on Tyr, Lys and Ser residues. Most of the dialkyl phosphate adducts were identified on Tyr residues. Methyl and ethyl modified histones were also detected. Eleven amino residues in histones showed non-enzymatic covalent methylation by exposure of dichlorvos and malathion. Our bottom-up proteomics approach showing histone-OPP adduct formation warrants future studies on the underlying mechanism of chronic illness from exposure to OPPs.

Bioaccumulation and Male Reproductive Toxicity of the New Brominated Flame Retardant Tetrabromobisphenol A-Bis(2,3-dibromo-2-methylpropyl ether) in Comparison with Hexabromocyclododecane.

Tetrabromobisphenol A-bis(2,3-dibromo-2-methylpropyl ether) (TBBPA-DBMPE) has come into use as an alternative to hexabromocyclododecane (HBCD), but it is unclear whether TBBPA-DBMPE has less hazard than HBCD. Here, we compared the bioaccumulation and male reproductive toxicity between TBBPA-DBMPE and HBCD in mice following long-term oral exposure after birth. We found that the concentrations of TBBPA-DBMPE in livers significantly increased with time, exhibiting a bioaccumulation potency not substantially different from HBCD. Lactational exposure to 1000 µg/kg/d TBBPA-DBMPE as well as 50 µg/kg/d HBCD inhibited testis development in suckling pups, and extended exposure up to adulthood resulted in significant molecular and cellular alterations in testes, with slighter effects of 50 µg/kg/d TBBPA-DBMPE. When exposure was extended to 8 month age, severe reproductive impairments including reduced sperm count, increased abnormal sperm, and subfertility occurred in all treated animals, although 50 µg/kg/d TBBPA-DBMPE exerted lower effects than 50 µg/kg/d HBCD. Altogether, all data led us to conclude that TBBPA-DBMPE exerted weaker male reproductive toxicity than HBCD at the same doses but exhibited bioaccumulation potential roughly equivalent to HBCD. Our study fills the data gap regarding the bioaccumulation and toxicity of TBBPA-DBMPE and raises concerns about its use as an alternative to HBCD.

Extended exposure to tetrabromobisphenol A-bis(2,3-dibromopropyl ether) leads to subfertility in male mice at the late reproductive age.

Tetrabromobisphenol A-bis(2,3-dibromopropyl ether) (TBBPA-BDBPE), a commonly used brominated flame retardant as a decabromodiphenyl ether substitute, has been detected in various environmental compartments, but its health hazards remain largely unknown. Our recent study showed that low-dose exposure of male mice to TBBPA-BDBPE from postnatal day (PND) 0 to 56 caused remarkable damage to the microtubule skeleton in Sertoli cells and the blood-testis barrier (BTB) but exerted little effect on conventional reproductive endpoints in adulthood. To investigate whether TBBPA-BDBPE may cause severe reproductive impairments at late reproductive age, here, we extended exposure of historically administrated male mice to 8-month age and allowed them to mate with non-treated females for the evaluation of fertility, followed by a general examination for the reproductive system. As expected, we found that 8-month exposure to 50 µg/kg/d as well as 1000 µg/kg/d TBBPA-BDBPE caused severe damage to the reproductive system, including reduced sperm counts, increased sperm abnormality, histological alterations of testes. Moreover, microtubule damage and BTB-related impairment were still observed following 8-month exposure. Noticeably, high-dose TBBPA-BDBPE-treated mice had fewer offspring with a female-biased sex ratio. All results show that long-term exposure to TBBPA-BDBPE caused severe reproductive impairment, including poor fertility at late reproductive age. It is therefore concluded that slight testicular injuries in early life can contribute to reproductive impairment at late reproductive age, highlighting that alterations in certain non-conventional endpoints should be noticed as well as conventional endpoints in future reproductive toxicity studies.

2,2',4,4'-tetrabromodipheny ether (BDE-47) disrupts gonadal development of the Africa clawed frog (Xenopus laevis).

Previous studies have shown that BDE-47, one of the most abundant polybrominated diphenyl ethers (PBDEs) congeners, has a weak estrogenic activity, but it has remained unclear whether BDE-47 disrupts gonadal development and causes male-to-female sex reversal in lower vertebrates, with limited and controversial data. The present study aimed to determine the effects of BDE-47 on gonadal development in Xenopus laevis, a model amphibian species for studying adverse effects of estrogenic chemicals on reproductive development. X. laevis at stage 45/46 were exposed to BDE-47 (0.5, 5, 50 nM) in semi-static system, with 1 nM 17ß-estradiol (E2) as the positive control. When reaching stage 53, tadpoles were examined for gonadal morphology, histology and sex-dimorphic gene expression. The phenotypic sex (gonadal morphology and histology) of each BDE-47-treated tadpole matched its genetic sex, showing no sex-reversal, whereas one half of genetic males treated with E2 displayed ovarian-like features. However, some genetic males (26%) in the 50 nM BDE-47 treatment group were found to contain more germ cells clumping together in the medulla, along with an increasing tendency of the gonad length/kidney length ratio in males, resembling feminizing outcomes of E2. These observations seem to suggest that BDE-47 exerted weak feminizing effects. However, BDE-47 induced increases in expression of both female-biased genes and male-biased genes in two sexes, which disagrees with feminizing outcomes, suggesting complicated effects of BDE-47 on gonadal development. Taken together, all results demonstrate that nanomolar BDE-47 disrupted gonadal development and exerted weak feminizing effects, but not resulted in male-to-female sex reversal in X. laevis.

Profile of organochlorine pesticides in soil cores from some hotspot areas of Beijing, China.

For the valid use of urban land and the safety of public health, an extensive contamination survey of organochlorine pesticides from five soil cores was conducted in the highly urbanized areas of Beijing in China. For topsoils in five soil cores, level of ∑HCHs and ∑DDTs varied from 0.174 to 4,783 ng g(-1) and 0.62 to 57,849 ng g(-1), respectively. The profile in topsoil of cores displayed that levels of pollutants in four soil cores from the urban areas with dense population are higher than that from outskirts. The depth characteristics of pollutants indicated that the level of ∑HCHs and ∑DDTs in BY and WU was close to/below the background value of soil in China (50 ng g(-1)), but those in some soil samples from A, B and ZX core, especially A and B, was above the threshold value for the soil safety (1,000 ng g(-1)). In views of the usage history of the land and profiles of contaminants, the source in A and B probably came from the dumped waste chemical materials in the old chemical factories. The study of soil cores sampled revealed the existence of chemical "time bomb" in urban regions of Beijing. Also, the finding indicated the absolute necessity of assessing the soil quality with the unprecedented land use changes in the big city community.

[Characteristics of patients and their medical cost on 14,398 hospitalized patients suffered form hepatitis B, from a hospital of infectious diseases located in Beijing].

OBJECTIVE: This article was to focus on the study of patient's profile, type and distribution of the disease and the related factors contributing to medical cost on 14 398 cases of hospitalized patients with hepatitis B from a hospital of infectious diseases located in Beijing, in order to provide basic information on optimizing the prevention and treatment strategies. METHODS: Information on hospital admission of patients with hepatitis B was collected and SPSS 16.0 statistics software package was used to analyze the profile, disease patterns distribution, structure of medical costs and main contributors related to medical costs. RESULTS: Through analysis, we found that the proportion of male patients was much bigger than that of female patients, with ratio as 2.9. The average age of patients with hepatitis B was 45.2 years old. The treatment process was time consuming, and the mortality rate was high. Our data showed that the mortality of hospitalized patients was up to 7% and the average age of death was 55 years old. Hepatitis B infection was easy to develop into chronic, cirrhosis and even liver cancer. For treatment cost, the largest cost share was the drugs being used which accounted for 62.4%. In terms of health care costs, it was high and the total cost of hospitalization was related to the following factors:days of hospitalization;complexity of the disease condition and the factors as the severity of the disease complications as surgery, frequencies of rescue, type of disease etc; basic information of the patients as age, occupation, origin. CONCLUSION: Compared with other diseases, the proportion of male patients with hepatitis B was much higher than that of the female. Hepatitis B had a longer duration and difficult, treatment high cost of medical care, poor prognosis, high mortality rate; Cost control, can not simply fixed by single disease, but by complexity of the disease and patient characteristics.

Profiles of organochlorine pesticides in earthworms from urban leisure areas of Beijing, China.

In this study, organochlorine pesticides (HCHs and DDTs) in earthworm and soil contacted closely with it were determined for the purpose of the risk assessment of chemicals in the urban leisure environment. The level of total hexachlorocyclohexanes and (HCHs) and dichlorodiphenyltrichloroethanes (DDTs) in earthworms was 0.6500-44.78 ng g(-1) and 18.97-1.112 x 104 ng g(-1), respectively. Absolutely high levels of DDT and its metabolites in earthworm and correlative soils samples, and the bioaccumulation factor (BAF) of DDTs probably presents certain risk to the higher trophic organisms through its food chain, especially birds.

Levels and chiral signatures of organochlorine pesticides in urban soils of Yinchuan, China.

In this study, residual level and enantiomeric composition of typical organochlorine pesticides (OCPs) were surveyed in urban soils of Yinchuan, China. The median levels of summation Sigma HCHs and summation Sigma DDTs were 0.852 and 2.24 ng/g, respectively, which suggested little risk for ecological environment and human health in the study area. Both chiral alpha-HCH and o,p'-DDT displayed the non-racemic signatures in all samples. The isomer ratios of summation Sigma HCHs and summation Sigma DDTs combined with enantiomer fractions (EFs) of alpha-HCH and o,p'-DDT, suggested that contamination source of HCHs derived from historical HCHs (including technical HCHs and Lindane) and that of DDTs originated from old source with the usage of mixed technical DDTs and dicofol.

[Correlations of high-risk human papillomaviral load to cervical intraepithelial neoplasia grades, expression of Ki-67 and P6ink4a and follow-up].

BACKGROUND & OBJECTIVE: It is well known that high-risk human papillomavirus (HPV) infection is the major cause of cervical cancer. However, the relation between cervical cancer and high-risk HPV load is uncertain, and there are only a small number of reports studying the correlation between high-risk HPV load and tumor markers. This study was to investigate the correlations of high-risk HPV load to the grade of cervical intraepithelial neoplasia (CIN), expression of Ki-67 and p16ink4a in the cervical lesion, and the abnormal cytology after surgery. METHODS: The expression of Ki-67 and p16ink4a in 8 specimens of CINI, 12 specimens of CINII, and 41 specimens of CINIII were detected by immunohistochemistry. All the patients received high-risk HPV load detection using hybrid captureII (HCII) before operation and were followed up afterwards. RESULTS: The high-risk HPV load was positively correlated to the CIN grade and expression of Ki-67 and p16ink4aû with correlation coefficients of 0.288, 0.318, and 0.336, respectively (P<0.05). After a mean follow-up of 18.5 months, 6 patients were found abnormal cytological smears again, whose HPV loads were over 100 RLU/ PC before operation. Five out of the 6 patients had the HPV loads between 100 to 1000 RLU/ PC before operation and the remaining one had the HPV load of over 1000 RLU/PC. However, no statistical differences were observed among the 3 groups of different viral loads (<100 RLU/PC, 100 to <1 000 RLU/PC, > or =1 000 RLU/PC). Age, parity, CIN grades, expression of p16ink4a and Ki-67 had no predictive significance for the abnormal cytology after operation. CONCLUSIONS: The high-risk HPV load has positive correlation to the progression of cervical lesion and increased malignancy of cells. Although the high-risk HPV load have no relation to the abnormal cytology after operation, patients with the viral load of over 100 RLU/PC should be paid more attention.

Contamination of soils with organochlorine pesticides in urban parks in Beijing, China.

Urban parks are an integral component of healthy urban living. Since they are frequently visited, an understanding of the environmental quality of these urban facilities is crucial. Here, a study was conducted on the contamination of soils in the parks of Beijing. Organochlorine pesticides (OCPs), which have the potential to cause endocrine disturbances, were considered study objectives. Hexachlorocyclohexanes (HCHs) were found at concentrations of 0.2490-197.0 ng g(-1) and dichlorodiphenyltrichloroethanes (DDTs) were found at concentrations of 5.942-1039 ng g(-1) in the soils investigated. The preliminary pollution assessment indicated that DDTs have caused high pollution levels in the soils of some parks. Analysis of the sources of contamination showed that HCHs in the soils were derived from an old mixed source of technical HCHs and lindane and that DDTs, which were suspected to have recent application to the soils at some sites, were derived mainly from a mixture of technical DDTs and dicofol containing DDT impurities. An independent sample t-test proved that pesticides containing DDTs had been used in large amounts in the soils of parks before 1983 (p<0.05) and that the levels of DDTs in the soils of parks administered by the Beijing municipal government were significantly higher than the levels in those administered by the district government (p<0.05). However, the main difference in this situation needs to be further studied. This study suggested that open spaces like urban parks were not as sound as was expected and that there was potential for exposure of visitors/workers in the parks to organochlorine pesticides.

[Changes of trace elements in regional lymph nodes of gastric carcinoma].

OBJECTIVE: To explore the relationship between the changes of trace elements and lymphatic metastasis in gastric carcinoma. METHODS: Trace elements including Fe, Mg, Mn, Ca, Cu, Zn, Se were measured in primary gastric carcinoma and regional lymph nodes from 40 patients with gastric carcinoma, and compared among the primary tumor, metastatic, and non-metastatic nodes. RESULTS: There were no significant differences in the contents of Fe, Mg, Mn and Ca among primary gastric tumors, regional lymph nodes with or without metastasis (P=0.372 - 0.741, P > 005), and no significant differences in the contents of all 7 trace elements between primary tumors and metastatic lymph nodes (P=0.15 - 0.59, P > 005). Compared with metastatic lymph nodes, the contents of Zn, Se significantly decreased, while Cu and Cu/Zn significantly increased (P=0.001 - 0.009, P< 0.01) in non-metastatic lymph nodes. The content of Zn in N2 positive lymph nodes was significant lower than that in N1 positive nodes (P=0.027). There were no significant difference in the contents of all 7 elements between intestinal type and diffuse type (P=0.149 - 0.758, P > 0.05). CONCLUSIONS: Lymphatic metastasis of gastric cancer is concomitant with the changes of trace elements, and the changes of Zn, Cu, Se may be related with lymphatic metastasis.

Distribution of persistent organochlorine pesticides in tissue/organ of silver carp (Hypophthalmichthys molitrix) from Guanting Reservoir, China.

The concentration of organochlorine pesticides (OCPs) in tissues and organs of silver carp (Hypophthalmichthys molitrix) from Guanting Reservoir were investigated to evaluate the pollution potential and distribution of OCPs. A total of 16 OCPs were measured and the concentrations were in the range of 1.61-69.01 ng/g wet weight (ww) for total OCPs, 0.16-0.75 ng/g ww for. HCB, 0.75-26.80 ng/g ww for sigmaHCH (sum of alpha-, beta-, gamma- and delta-HCH) and 0.68-35.94 ng/g ww for sigmaDDT( sum of p, p'-DDE, p, p'-DDD, o, p'-DDT and p, p'-DDT). The mean concentrations of total OCPs, HCB, sigmaHCH, and sigmaDDT were 18.04, 0.96, 7.14 and 9.28 ng/g ww, respectively. Among the organochlorine pesticides, beta-HCH and p, p'-DDE were the most dominant compounds in tissue and organ with the average concentrations of 4.42 and 8.14 ng/g, respectively. The results obtained in this study show that the levels of 16 OCP residues found in silver carps are low and pose no threat to human health and wildlife fed upon them on the basis of existing related quality guidelines. However, recent input of lindane and DDT might still exist in the area investigated and further investigation should be carried on.