Breast cancer among Alaska Native women potentially exposed to environmental organochlorine chemicals

OBJECTIVES

To determine if an increased rate of breast cancer in Alaska Native women is related to their consumption of a subsistence diet that may contain p,p'-dichlorodiphenylethylene (DDE) and polychlorinated biphenyls (PCBs).

STUDY DESIGN

A retrospective case control design.

METHODS

We analyzed banked serum collected between 1981 and 1987 from 126 Alaska Native women, including 63 case women who subsequently developed breast cancer and 63 age-matched control women who remained cancer-free. Serum was analyzed for DDT, DDE, 13 other chlorinated pesticides, and 28 PCB congeners.

RESULTS

The geometric mean for p,p'-DDE levels among case women was 8.67 ppb (95% Confidence Interval 7.48, 10.04); among control women, the geometric mean was 7.36 ppb (6.53, 8.30). The geometric mean for total PCB levels among case women was 4.55 ppb (3.61, 5.74) and for control women, the geometric mean was 6.10 ppb (4.73, 7.86). Cancer status and total PCB levels varied across ethnicity (i.e., Eskimo, Aleut, and Indian) but DDE levels were uniform among these ethnic groups. Using conditional logistic regression analysis to adjust for potential confounders (e.g., ethnicity, family history of breast cancer, parity), we found an odds ratio of 1.43 (0.46, 4.47) for the highest tertile of DDE exposure and 0.42 (0.07, 2.38) for the highest tertile of total PCB exposure.

CONCLUSIONS

Although the results are limited by small sample size and restricted risk factor information, our findings of higher DDE levels, but lower PCB levels among women with breast cancer are consistent with previous research. Our results confirm exposure to organochlorines among Alaska Native women but do not identify these exposures as a significant risk factor for breast cancer.

Persistent organic pollutants (POPs) and metals in primiparous women: a comparison from Canada and Mexico

Under the North American Commission for Environmental Cooperation (CEC) and its Sound Management of Chemicals (SMOC) program, a tri-national human contaminant monitoring initiative was completed to provide baseline exposure information for several environmental contaminants in Canada, Mexico and the United States (U.S). Blood samples were collected from primiparous women in Canada and Mexico, and were analysed for a suite of environmental contaminants including polychlorinated biphenyls (PCBs), dichlorodiphenyldichloroethylene(p,p'-DDE),beta-hexachlorocyclohexane (β-HCH), mercury and lead. A multiple stepwise linear regression analysis was conducted using data from Canadian and Mexican primiparous mothers, adjusting for ethnicity group, age, pre-pregnancy BMI, years at current city and ever-smoking status. Concentrations of p,p'-DDE, β-HCH, and lead were found to be higher among Mexican participants; however, concentrations of most PCBs among Mexican participants were similar to Canadian primiparous women after adjusting for covariates. Concentrations of total mercury were generally higher among Mexican primiparous women although this difference was smaller as age increased. This initial dataset can be used to determine priorities for future activities and to track progress in the management of the selected chemicals, both domestically and on a broader cooperative basis within North America.

Dioxin exposure and cancer risk in the Seveso Women's Health Study

BACKGROUND

2,3,7,8-Tetrachlorodibenzo-para-dioxin (TCDD), a widespread environmental contaminant, disrupts multiple endocrine pathways. The International Agency for Research on Cancer classified TCDD as a known human carcinogen, based on predominantly male occupational studies of increased mortality from all cancers combined.

OBJECTIVES

After a chemical explosion on 10 July 1976 in Seveso, Italy, residents experienced some of the highest levels of TCDD exposure in a human population. In 1996, we initiated the Seveso Women's Health Study (SWHS), a retrospective cohort study of the reproductive health of the women. We previously reported a significant increased risk for breast cancer and a nonsignificant increased risk for all cancers combined with individual serum TCDD, but the cohort averaged only 40 years of age in 1996. Herein we report results for risk of cancer from a subsequent follow-up of the cohort in 2008.

METHODS

In 1996, we enrolled 981 women who were 0-40 years of age in 1976, lived in the most contaminated areas, and had archived sera collected near the explosion. Individual TCDD concentration was measured in archived serum by high-resolution mass spectrometry. A total of 833 women participated in the 2008 follow-up study. We examined the relation of serum TCDD with cancer incidence using Cox proportional hazards models.

RESULTS

In total, 66 (6.7%) women had been diagnosed with cancer. The adjusted hazard ratio (HR) associated with a 10-fold increase in serum TCDD for all cancers combined was significantly increased [adjusted HR = 1.80; 95% confidence interval (CI): 1.29, 2.52]. For breast cancer, the HR was increased, but not significantly (adjusted HR = 1.44; 95% CI: 0.89, 2.33).

CONCLUSIONS

Individual serum TCDD is significantly positively related with all cancer incidence in the SWHS cohort, more than 30 years later. This all-female study adds to the epidemiologic evidence that TCDD is a multisite carcinogen.

Hypospadias and halogenated organic pollutant levels in maternal mid-pregnancy serum samples

BACKGROUND

Environmental contaminants that disrupt endocrine function may contribute to hypospadias etiology.

OBJECTIVE

To compare levels of selected halogenated organic pollutants in women delivering infants with and without hypospadias.

METHODS

This study examined levels of nine polybrominated flame retardants (PBDEs), 30 polychlorinated biphenyls (PCBs) and nine persistent pesticides in mid-pregnancy serum samples from 20 women who delivered infants with hypospadias and 28 women who delivered unaffected infants, in California. Analytes were measured using isotope dilution high-resolution mass spectrometry. Values below individual limits of detection (LOD) for each analyte were imputed based on a truncated multivariate normal distribution. Levels of 17 analytes for which at least 50% of cases and controls had values above the LOD were compared using t-tests and by generating odds ratios from logistic regression analyses.

RESULTS

Means were greater for cases than controls for 11 of the 17 reported analytes (4 of 5 PBDEs, 7 of 9 PCBs, and 0 of 3 other persistent pesticides), but none of the differences were statistically significant. Eleven of the 17 odds ratios exceeded one (the same analytes that had greater means), but none of the confidence intervals excluded one. After adjustment for sample processing time and foreign-born Hispanic race-ethnicity, only four of the odds ratios exceeded one.

CONCLUSIONS

Levels of the PBDEs and PCBs were not statistically significantly different, but the sample size was small. The current study adds to a relatively limited knowledge base regarding the potential association of specific contaminants with hypospadias or other birth defects.

Serum dioxin concentrations and time to pregnancy

BACKGROUND

Pollution may play a role in population trends of declining semen quality and regional differences in time to pregnancy (TTP) in industrialized societies. Dioxins including 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) have been suspected. In 1976, an explosion near Seveso, Italy resulted in the highest TCDD exposure known in residential populations. Twenty years later, we conducted a retrospective cohort study, the Seveso Women's Health Study.

METHODS

Of 981 participants, 472 women attempted pregnancy after the explosion, and 278 delivered a livebirth not associated with contraceptive failure. Individual serum TCDD levels were measured from samples collected soon after the explosion and extrapolated to the conception attempt. We examined the relation of TCDD levels to time to pregnancy (parameterized as the monthly probability of conception within the first 12 months of trying) and to infertility (defined as conception after at least 12 months of trying). We modeled fecundability with discrete-time Cox proportional hazards regression, and we modeled fertility with logistic regression. We tested the sensitivity of the conclusions to differing definitions of eligibility and outcome.

RESULTS

Median TCDD level was 50 parts per trillion, median time to pregnancy was 2 months, and 17% reported taking 12 or more months to conceive. For every 10-fold increase in serum TCDD, we observed a 25% increase in time to pregnancy (adjusted-fecundability odds ratio = 0.75 [95% confidence interval (CI) = 0.60-0.95]) and about a doubling in odds of infertility (adjusted odds ratio = 1.9 [95% CI = 1.1-3.2]). Results were similar for extrapolated TCDD and sensitivity analyses.

CONCLUSIONS

We found dose-related increases in TTP and infertility associated with individual serum TCDD levels in the women from Seveso, Italy. These findings may have implications for fertility in industrialized areas.

Partitioning of polybrominated diphenyl ethers (PBDEs) in serum and milk from the same mothers

We and others have previously described partitioning of chemicals, including polychlorinated-p-dioxins, dibenzofurans, and biphenyls in different types of human tissues and fluids, including blood and milk. Additionally, we previously reported the blood to milk partitioning of polybrominated diphenyl ethers (PBDEs) in a group of 11 women. Partitioning is of importance in understanding the toxicokinetics of these compounds and also in clinical medicine in improving estimates of levels in different matrices including blood and milk. In this study we extend these findings, describing the levels of PBDEs detected in the serum and milk of 29 women from Texas. The median sum of the levels of the four most detected congeners (BDE 47, 99, 100, and 153) in serum was 27.8 ng g(-1) lipid (range 6.7-501.6 ng g(-1) lipid). In milk, the median sum of the levels of the same congeners was 39.7 ng g(-1) lipid (range 12.9-580.3 ng g(-1) lipid). The levels detected in breast milk in this study are similar to those we reported in 2003, where a median total PBDE level of 34 ng g(-1) lipid was reported. When congener specific blood to milk partitioning ratios were calculated for BDEs 47, 99, 100, and 153, the relatively small tetrabrominated congener, BDE 47, was found in higher concentrations in milk compared to blood, while the higher molecular weight hexabrominated congener, BDE 153, was found in approximately equal quantities in blood and milk, on a lipid normalized basis. The reason for the differential partitioning of PBDE congeners in milk and blood could be due to variation in toxicokinetics, specifically distribution based on molecular size or molecular weight.

Polycyclic aromatic hydrocarbon metabolite levels and pediatric allergy and asthma in an inner-city cohort

Exposure to polycyclic aromatic hydrocarbons (PAH) has been associated with allergic sensitization and asthma. We hypothesized that increased urinary PAH metabolites are associated with allergy or asthma among children age 5 yrs in an inner-city birth cohort. As part of an ongoing prospective birth cohort under the auspices of the Columbia Center for Children's Environmental Health (CCCEH), urine was collected from 5-yr-old children (n = 222) of Dominican American and African American mothers in Northern Manhattan and South Bronx of New York City. Twenty-four PAH metabolites were measured in these specimens, and their levels (unadjusted and specific gravity corrected) were evaluated with IgE levels and asthma outcomes. Ten metabolites were detected in urine from all children. Concentrations ranged higher than those in representative samples of US children ages 6-11 in the National Health and Nutrition Examination Survey (NHANES). Among CCCEH children, compared with African Americans, the Dominican children had higher 2-hydroxynaphthalene but lower 9-hydroxyfluorene and 4-hydroxyphenanthrene concentrations. Increased 3-hydroxyfluorene and 3-hydroxyphenanthrene levels were associated with higher anti-mouse IgE levels (p < 0.05). These plus 2-hydroxynaphthalene, 2-hydroxyflourene and 1-hydroxyphenanthrene concentrations were associated with higher anti-mouse IgE levels on multivariate analyzes. Increased 2-hydroxyphenanthrene, 3-hydroxyphenanthrene and 4-hydroxyphenanthrene levels were associated with higher anti-cat IgE levels (p < 0.05) in univariate, but not multivariate, analyzes. Levels of PAH metabolites were not associated with respiratory symptoms. Measures of PAH metabolites suggest considerable exposure in an urban pediatric population, and possible associations with allergic sensitization to mouse.

In vitro and in vivo anti-leukemia activity of CHR-2845, a cell-targeted HDAC inhibitor for use in monocytic leukemia

e14579

Background: Histone deacetylase inhibitors alter gene expression and induce apoptosis in a wide range of cancer cells including those derived from human leukemias. CHR-2845 is a novel hydroxamic acid derivative histone deacetylase inhibitor (HDACi) which is a selective substrate for the intracellular carboxylesterase hCE-1, whose expression is restricted to cells of the monocyte- macrophage lineage. Methods: We studied the in vitro and in vivo anti-leukemia activity of CHR-2845 using cell proliferation assay, annexin V binding assay, cell cycle analysis, western blot and in vitro primary leukemia cell culture. Results: Both U937 and THP1 cells express high levels of hCE-1 whereas the myeloid cell line, HL60, does not. In comparison to vorinostat, CHR-2845 showed increased anti-proliferative potency (IC50) against monocytic cell lines (THP1, 30 nM vs 700 nM and U937, 30 nM vs 475 nM), compared to a myeloid cell line (HL60, 700nM vs 470 nM). In a broad panel of leukemic cell lines, the potency of CHR-2845 over vorinostat correlated completely with hCE-1 expression. In monocytic cell lines, CHR-2845 induced more apoptosis than vorinostat (THP1: 45±5% vs 11±1% and U937: 23±14% vs 6±1%), as measured by flow cytometry using Annexin V. Biochemical assessment of histone H3 and H4 protein acetylation by Western blot also indicateed that CHR-2845 is at least 10 times more potent than vorinostat in monocytic cell lines but not in HL-60 cells. This increase in histone acetylation was associated with increased phosphohistone H2AX, indicating formation of double-strand DNA breaks induced by this compound. These data for CHR-2845 and vorinostat on apoptosis and histone acetylation in THP1 and U937 versus HL60 cells, confirmed the selectivity of this novel compound for cells of the monocytic lineage. We also studied the anti-leukemia activity of CHR-2845 in primary leukemia cells from 8 patients with acute or chronic myelomonocytic leukemia. CHR-2845 decreased proliferation and induced apoptosis more than an equivalent dose of vorinostat in some of the patients we studied. Conclusions: These results indicated that CHR-2845 has potential to be efficacious in the treatment of patients with monocytic leukemia.

[Table: see text]

Serum dioxin concentrations and risk of uterine leiomyoma in the Seveso Women's Health Study

Uterine leiomyomata (fibroids), benign neoplasms of the smooth muscle, are a major cause of hysterectomy. Exposure to hormonally active chemicals may play an etiologic role. The authors investigated the risk of uterine leiomyoma associated with exposure to 2,3,7,8,-tetrachlorodibenzo-p-dioxin (TCDD) for women who resided near Seveso, Italy, in 1976 at the time of a chemical explosion. Twenty years later, women enrolled in the Seveso Women's Health Study were asked about history of fibroids, medical records were obtained, and vaginal ultrasonography was performed for a subset. Serum collected soon after the explosion was analyzed for TCDD. A likelihood-based method that combines both historical and current status (ultrasound) data was adapted to estimate the hazard ratio. Of 956 eligible women, 251 (26.3%) had fibroids. Compared with that for women with TCDD levels of < or = 20 parts per trillion, the age-adjusted hazard ratios were 0.58 (95% confidence interval: 0.41, 0.81) for women with levels of 20.1-75.0 parts per trillion and 0.62 (95% confidence interval: 0.44, 0.89) for women with levels of >75.0 parts per trillion. This finding suggests that TCDD may have antiestrogenic effects in the uterine myometrium, in contrast to apparently estrogenic effects previously found in the breast of Seveso Women's Health Study women.

Interaction between cytochrome P450 gene polymorphisms and serum organochlorine TEQ levels in the risk of endometriosis

Exposure to dioxins and polychlorinated biphenyls (PCBs) has been suggested as a possible etiologic factor for endometriosis, but the association remains highly controversial. To assess whether cytochrome P450 (CYP) gene polymorphisms modulate the effect of dioxins and/or PCBs in endometriosis risk, we conducted a case-control study among infertile Japanese women. A total of 138 eligible women aged 20-45 were diagnosed laparoscopically and classified into three subgroups: control (no endometriosis), early endometriosis (stages I-II) and advanced endometriosis (stages III-IV). Neither CYP1A1 Ile462Val and CYP1B1 Leu432Val polymorphisms (genotypes with versus genotypes without the minor allele) nor serum dioxin and PCB toxic equivalency (TEQ) levels (low versus high) were independently associated with either early or advanced endometriosis risk. However, genotypes with the CYP1A1 462Val allele showed a statistically significant reduced risk of advanced endometriosis in combination with high serum dioxin TEQ levels (adjusted odds ratio = 0.13, 95% confidence interval: 0.02-0.76) (P for interaction = 0.08). Although no association was found between serum PCB TEQ level and advanced endometriosis in any stratum of CYP1B1 Leu432Val polymorphism, a statistically significant interaction was found (P for interaction = 0.05). CYP1A1 and CYP1B1 polymorphisms may modify the relation between environmental exposure to organochlorine and advanced endometriosis risk.

Serum dioxin concentrations and quality of ovarian function in women of Seveso

BACKGROUND

Although 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) has been associated with alterations in ovarian function and hormones in animals, it has not been studied in humans. On 10 July 1976, an explosion exposed residents of Seveso, Italy, to the highest levels of TCDD in a population. Twenty years later, we initiated the Seveso Women's Health Study to study reproductive health.

OBJECTIVE

We related TCDD levels measured in sera collected near the time of explosion and ovarian function (ovarian cysts, ovarian follicles, ovulation rate, serum hormones) at follow-up.

METHODS

We included 363 women who were 20-40 years of age and nonusers of oral contraceptives. We examined the relationship of 1976 serum TCDD levels with ultrasound-detected ovarian follicles among 96 women in the menstrual follicular phase and serum hormone levels (estradiol, progesterone) among 129 women in the menstrual luteal phase at follow-up. Ovulation was defined by serum progesterone levels > 3 ng/mL.

RESULTS

The median serum TCDD level was 77.3 ppt, lipid-adjusted. Serum TCDD was not associated with number or size of ovarian follicles. Of women in the luteal phase, 87 (67%) ovulated. Serum log(10)TCDD was not associated with odds of ovulation [adjusted odds ratio = 0.99; 95% confidence interval (CI), 0.5 to 1.9]. Among those who had ovulated, serum log(10)TCDD was not associated with serum progesterone [adjusted beta (adj-beta ) = -0.70; 95% CI, -2.4 to 1.0] or estradiol (adj-beta = -1.81; 95% CI, -10.4 to 6.8).

CONCLUSIONS

We found no clear evidence that 1976 TCDD exposure was associated with ovarian function 20 years later in women exposed to relatively high levels in Seveso, Italy.

The use of biomonitoring data in exposure and human health risk assessments

Biomonitoring uses analytic methods that permit the accurate measurement of low levels of environmental chemicals in human tissues. However, depending on the intended use, biomonitoring, like all exposure tools, may not be a stand-alone exposure assessment tool for some of its environmental public health uses. Although biomonitoring data demonstrate that many environmental chemicals are absorbed in human tissues, uncertainty exists regarding if and at what concentrations many of these chemicals cause adverse health outcomes. Moreover, without exposure pathway information, it is difficult to relate biomonitoring results to sources and routes of exposure and develop effective health risk management strategies. In September 2004, the Health and Environmental Sciences Institute, U.S. Environmental Protection Agency, Centers for Disease Control and Prevention, Agency for Toxic Substances and Disease Registry, and International Council of Chemical Associations co-sponsored the International Biomonitoring Workshop, which explored the processes and information needed for placing biomonitoring data into perspective for risk assessment purposes, with special emphasis on integrating biomarker measurements of exposure, internal dose, and potential health outcome. Scientists from international governments, academia, and industry recommended criteria for applying biomonitoring data for various uses. Six case studies, which are part of this mini-monograph, were examined: inorganic arsenic, methyl eugenol, organophosphorus pesticides, perfluorooctanesulfonate, phthalates, and polybrominated diphenyl ethers. Based on the workshop and follow-up discussions, this overview article summarizes lessons learned, identifies data gaps, outlines research needs, and offers guidance for designing and conducting biomonitoring studies, as well as interpreting biomonitoring data in the context of risk assessment and risk management.

Children's residential exposure to chlorpyrifos: application of CPPAES field measurements of chlorpyrifos and TCPy within MENTOR/SHEDS-Pesticides model

The comprehensive individual field-measurements on non-dietary exposure collected in the Children's-Post-Pesticide-Application-Exposure-Study (CPPAES) were used within MENTOR/SHEDS-Pesticides, a physically based stochastic human exposure and dose model. In this application, however, the model was run deterministically. The MENTOR/SHEDS-Pesticides employed the CPPAES as input variables to simulate the exposure and the dose profiles for seven children over a 2-week post-application period following a routine residential and professional indoor crack-and-crevice chlorpyrifos application. The input variables were obtained from a personal activity diary, microenvironmental measurements and personal biomonitoring data obtained from CPPAES samples collected from the individual children and in their homes. Simulation results were compared with CPPAES field measured values obtained from the children's homes to assess the utility of the different microenvironmental data collected in CPPAES, i.e. indicator toys and wipe samplers to estimate aggregate exposures that can be result from one or more exposure pathways and routes. The final analyses of the database involved comparisons of the actual data obtained from the individual biomarker samples of a urinary metabolite of chlorpyrifos (TCPy) and the values predicted by MENTOR/SHEDS-Pesticides using the CPPAES-derived variables. Because duplicate diet samples were not part of the CPPAES study design, SHEDs-Pesticides simulated dose profiles did not account for the dietary route. The research provided more confidence in the types of data that can be used in the inhalation and dermal contact modules of MENTOR/SHEDS-Pesticides to predict the pesticide dose received by a child. It was determined that we still need additional understanding about: (1) the types of activities and durations of activities that result in non-dietary ingestion of pesticides and (2) the influence of dietary exposures on the levels of TCPy found in the urine.

Strategic biomonitoring initiatives: moving the science forward

Biomonitoring programs in the United States and Europe demonstrate the vast array of data that are publicly available for the evaluation of exposure trends, identification of susceptible populations, detection of emerging chemical risks, the conduct of epidemiology studies, and evaluation of risk reduction strategies. To cultivate international discussion on these issues, the ILSI Health and Environmental Sciences Institute convened a scientific session at its annual meeting in January 2006 on "Integration of Biomonitoring Exposure Data into the Risk Assessment Process." This Forum paper presents perspectives from session speakers on the biomonitoring activities of the Centers for Disease Control and Prevention, the U.S. Environmental Protection Agency, the National Research Council Committee on Human Biomonitoring for Environmental Toxicants, the German Commission on Human Biomonitoring, and the Health and Environmental Sciences Institute Biomonitoring Technical Committee. Speakers noted that better estimates of biological concentrations of substances in the tissues of human populations can be combined with other exposure indices, as well as epidemiological and toxicologic data, to improve risk estimates. With this type of combined data, the potential also exists to define exposure levels at which hazard and risk are of minimal concern. Limitations in interpreting biomonitoring data were discussed, including the need for different criteria for applying biomonitoring data for exposure assessment, risk assessment, risk management, or disease prevention purposes. As efforts and resources are expended to improve the ability to apply biomonitoring exposure data in the risk assessment process, it is equally important to communicate the significance of such data to the public.

Fish intake and serum levels of organochlorines among Japanese women

This study evaluates background serum levels of selected organochlorine compounds among Japanese women of reproductive age and investigates whether lifestyle factors, especially dietary factors, may be associated with these levels. A cross-sectional study was performed on 80 Japanese women, aged 26-43 years, who complained of infertility and were confirmed not to have endometriosis. The serum levels of total toxic equivalency (TEQ), 18 polychlorinated dibenzo-p-dioxins (PCDDs)/polychlorinated dibenzofurans (PCDFs), 4 coplanar polychlorinated biphenyls (cPCBs), 36 ortho-substituted polychlorinated biphenyls (PCBs), and 13 chlorinated pesticides or their metabolites were measured and data were collected on the women's age, residence, occupation, body mass index (BMI), smoking and alcohol habit and 6 dietary intakes (fish, meats, rice, vegetables, fruits and dairy products). The serum median level of total TEQ was 25.1 pg TEQ/g lipid, that of PCDDs/PCDFs/cPCBs was 11.5 pmol/g lipid, that of PCBs was 0.46 nmol/g lipid, and that of total pesticides was 1.32 nmol/g lipid. The serum levels of total TEQ, PCDDs/PCDFs/cPCBs, PCBs and pesticides were positively associated with age (P for trend=0.003, 0.01, 0.005 and 0.01, respectively) and frequent fish consumption (P for trend=0.002, 0.003, 0.0003 and 0.006, respectively). Other lifestyle factors were not associated with serum organochlorine levels. The present study suggests that Japanese women who consume fish frequently in their reproductive period tend to accumulate organochlorines in their bodies.

Associations between serum levels of selected organochlorine compounds and endometriosis in infertile Japanese women

Endocrine-disrupting chemicals (EDCs) have been proposed as risk factors for endometriosis. Persistent organochlorine compounds, a group of suspected EDCs, are present to some extent in almost all human adipose tissue and blood via the food chain. A few animal studies have confirmed that exposure to these compounds can increase the incidence of endometriosis. In this study, we examined the associations between endometriosis and exposure to selected organochlorine compounds, including 8 polychlorinated dibenzo-p-dioxins (PCDDs), 10 polychlorinated dibenzofurans (PCDFs), 4 coplanar polychlorinated biphenyls (cPCBs), 36 ortho-substituted polychlorinated biphenyls (PCBs), and 13 chlorinated pesticides or their metabolites. The participants were 139 infertile Japanese women who were examined by laparoscopy and diagnosed as either endometriosis cases (Stages II-IV) or controls (Stages 0-I). The serum levels (lipid adjusted) of the targeted organochlorine compounds were in both 58 cases and 81 controls. There were very few differences in the various levels between endometriosis cases and controls. The total serum toxic equivalency (TEQ) value of PCDDs was significantly higher in the controls than in the cases (P=0.02). No other total TEQ values differed between cases and controls. For PCDDs, PCDFs, cPCBs, and PCBs, the multivariate odds ratio was 0.38 [95% confidence interval (CI), 0.12-1.17] and 0.41 (95% CI, 0.14-1.27) for the third and highest quartiles, respectively, compared to the lowest quartile of total TEQ values. A weak, negative dose-response relationship was evident for total TEQs (P for trend of 0.06). The results of this study provide some evidence that serum levels of these organochlorine compounds are not associated with an increased risk of endometriosis in infertile Japanese women.

In utero exposure to background levels of polychlorinated biphenyls and cognitive functioning among school-age children

Polychlorinated biphenyls (PCBs) are ubiquitous environmental contaminants. In utero exposure to background levels of PCBs has been associated with intellectual impairment among children in most, but not all, studies. The authors evaluated prenatal PCB exposure in relation to cognitive test (intelligence quotient (IQ)) scores on the Wechsler Intelligence Scale for Children at age 7 years. Pregnant women were recruited from 12 US study centers from 1959 to 1965, and their children were followed until age 7 years (the Collaborative Perinatal Project). Third trimester serum was analyzed for PCBs in 1997-1999 for 732 women selected at random and for an additional 162 women whose children had either a low or a high IQ score. The PCB-IQ association was examined in multivariate models. Among those in the lowest exposure category (<1.25 microg of PCB/liter of serum), the fully adjusted mean IQ score was 93.6 (standard error: 1.8); among those in the highest category (> or =5 microg of PCB/liter), the mean IQ was 97.6 (standard error: 1.2); and overall the increase in IQ per unit increase in PCB level (microg/liter) was 0.22 (95% confidence interval: -0.28, 0.71). In these data, in utero exposure to background levels of PCBs was not associated with lower IQ at age 7 years.

Serum dioxin concentrations and age at menopause

2,3,7,8-Tetrachlorobenzo-p-dioxin (TCDD), a halogenated compound that binds the aryl hydrocarbon receptor, is a by-product of numerous industrial processes including waste incineration. Studies in rats and monkeys suggest that TCDD may affect ovarian function. We examined the relationship of TCDD and age at menopause in a population of women residing near Seveso, Italy, in 1976, at the time of a chemical plant explosion. We included 616 of the women who participated 20 years later in the Seveso Women's Health Study. All women were premenopausal at the time of the explosion, had TCDD levels measured in serum collected soon after the explosion, and were > or = 35 years of age at interview. Using proportional hazards modeling, we found a 6% nonsignificant increase in risk of early menopause with a 10-fold increase in serum TCDD. When TCDD levels were categorized, compared with women in the lowest quintile (< 20.4 ppt), women in quintile 2 (20.4-34.2 ppt) had a hazard ratio (HR) of 1.1 (p = 0.77), quintile 3 (34.3-54.1 ppt) had an HR of 1.4 (p = 0.14), quintile 4 (54.2-118 ppt) had an HR of 1.6 (p = 0.10), and quintile 5 (> 118 ppt) had an HR of 1.1 (p = 0.82) for risk of earlier menopause. The trend toward earlier menopause across the first four quintiles is statistically significant (p = 0.04). These results suggest a nonmonotonic dose-related association with increasing risk of earlier menopause up to about 100 ppt TCDD, but not above.

Chlorpyrifos accumulation patterns for child-accessible surfaces and objects and urinary metabolite excretion by children for 2 weeks after crack-and-crevice application

The Children's Post-Pesticide Application Exposure Study (CPPAES) was conducted to look at the distribution of chlorpyrifos within a home environment for 2 weeks after a routine professional crack-and-crevice application and to determine the amount of the chlorpyrifos that is absorbed by a child living within the home. Ten residential homes with a 2- to 5-year-old child in each were selected for study, and the homes were treated with chlorpyrifos. Pesticide measurements were made from the indoor air, indoor surfaces, and plush toys. In addition, periodic morning urine samples were collected from each of the children throughout the 2-week period. We analyzed the urine samples for 3,5,6-trichloropyridinol, the primary urinary metabolite of chlorpyrifos, and used the results to estimate the children's absorbed dose. Average chlorpyrifos levels in the indoor air and surfaces were 26 (pretreatment)/120 (posttreatment) ng/m3 and 0.48 (pretreatment)/2.8 (posttreatment) ng/cm2, respectively, reaching peak levels between days 0 and 2; subsequently, concentrations decreased throughout the 2-week period. Chlorpyrifos in/on the plush toys ranged from 7.3 to 1,949 ng/toy postapplication, with concentrations increasing throughout the 2-week period, demonstrating a cumulative adsorption/absorption process indoors. The daily amount of chlorpyrifos estimated to be absorbed by the CPPAES children postapplication ranged from 0.04 to 4.8 microg/kg/day. During the 2 weeks after the crack-and-crevice application, there was no significant increase in the amount of chlorpyrifos absorbed by the CPPAES children.

In utero exposure to polychlorinated biphenyls and sensorineural hearing loss in 8-year-old children

Early-life exposure to polychlorinated biphenyls (PCBs), a ubiquitous environmental contaminant, increases the hearing threshold at selected frequencies in rats. Among humans from the Faroe Islands with unusually high early-life PCB exposure, exposure was directly associated with increased hearing thresholds at two frequencies, although the deficits were present in the left ear but not the right. We examined PCB levels in maternal pregnancy serum in relation with audiometrically determined hearing thresholds among offspring when they were of school age. Complete data were available for 195 children with sensorineural hearing loss (SNHL) and 615 children selected at random, all of whom were born in 1959-1966 in the Collaborative Perinatal Project (CPP) U.S. cohort. The median exposure among those selected at random, as reflected by the mother's third trimester serum total PCB concentration, was 2.8 microg/l, about twofold higher than recent background levels in the United States. Based on the average hearing threshold across the frequencies essential for speech recognition in the "worst ear," the maternal serum PCB level was unrelated to the adjusted odds of SNHL or to adjusted mean hearing threshold. Overall, an adverse effect of early-life, background-level PCB exposure on SNHL was not supported by these data.

Developmental dental aberrations after the dioxin accident in Seveso

Children's developing teeth may be sensitive to environmental dioxins, and in animal studies developing teeth are one of the most sensitive targets of toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Twenty-five years after the dioxin accident in Seveso, Italy, 48 subjects from the contaminated areas (zones A and B) and in patches lightly contaminated (zone R) were recruited for the examination of dental and oral aberrations. Subjects were randomly invited from those exposed in their childhood and for whom frozen serum samples were available. The subjects were frequency matched with 65 subjects from the surrounding non-ABR zone for age, sex, and education. Concentrations of TCDD in previously analyzed plasma samples (zone ABR subjects only) ranged from 23 to 26,000 ng/kg in serum lipid. Ninety-three percent (25 of 27) of the subjects who had developmental enamel defects had been < 5 years of age at the time of the accident. The prevalence of defects in this age group was 42% (15 of 36) in zone ABR subjects and 26% (10 of 39) in zone non-ABR subjects, correlating with serum TCDD levels (p = 0.016). Hypodontia was seen in 12.5% (6 of 48) and 4.6% (3 of 65) of the zone ABR and non-ABR subjects, respectively, also correlating with serum TCDD level (p = 0.05). In conclusion, developmental dental aberrations were associated with childhood exposure to TCDD. In contrast, dental caries and periodontal disease, both infectious in nature, and oral pigmentation and salivary flow rate were not related to the exposure. The results support our hypothesis that dioxins can interfere with human organogenesis.

Serum dioxin concentrations and age at menarche

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD), a widespread environmental contaminant, is associated with delays in pubertal development in animal studies. On 10 July 1976, as a result of a chemical explosion, residents of Seveso, Italy, experienced the highest levels of TCDD exposure experienced by a human population. Twenty years later, we initiated the Seveso Women's Health Study (SWHS), a retrospective cohort study of female residents of the most contaminated areas, to determine whether the women were at higher risk for reproductive disease. We examined the association of TCDD serum levels, based on measurements in serum collected soon after the explosion, with reported age at menarche among the 282 SWHS women who were premenarcheal at the time of the explosion. We found no change in risk of onset of menarche with a 10-fold increase in TCDD (e.g., 10-100 ppt; hazard ratio = 0.95; 95% confidence interval, 0.83-1.09; p-value for trend = 0.46). When TCDD levels were categorized, there was also no evidence of a dose-response trend (p = 0.65). In summary, we found that individual serum TCDD measurements are not significantly related to age at menarche among women in the SWHS cohort. The women in this study experienced substantial TCDD exposure during the postnatal but prepubertal developmental period. Given that animal evidence suggests in utero exposure has the most significant effect on onset of puberty, continued follow-up of the offspring of the SWHS cohort is important.

Relationship of serum TCDD concentrations and age at exposure of female residents of Seveso, Italy

In 1976, a chemical plant explosion near Seveso, Italy, resulted in the highest known exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in residential populations. In 1996, we initiated the Seveso Women's Health Study (SWHS), a historical cohort study of females who were 40 years old at the time of explosion and residents of the most heavily contaminated areas, zones A and B. Serum samples collected near the time of the explosion were analyzed for TCDD. We also analyzed pooled serum samples collected in 1976 from females who resided in zone non-ABR, the "unexposed" zone, to assess concurrent background exposures to other dioxins, furans, and coplanar polychlorinated biphenyls (PCBs). The median lipid-adjusted TCDD level for residents of zones A and B combined was 56 ppt (range = 2.5-56,000 ppt). Zone A residents had 5-fold higher TCDD levels (n = 67, median = 272 ppt) than did zone B residents (n = 814, median = 47 ppt). The youngest children had the highest TCDD levels, which decreased with age at explosion until approximately 13 years of age and were constant thereafter. Therefore, children living in zones A and B received a disproportionately higher exposure to TCDD as a result of the explosion. Zone of residence and age were the strongest predictors of TCDD level. Chloracne, nearby animal mortality, location (outdoors vs. indoors) at the time of explosion, and consumption of homegrown food were also related to serum TCDD levels. The serum pools from zone non-ABR residents had an average TCDD concentration of 20.2 ppt, and average total toxic equivalent (TEQ) concentration of 100.4 ppt. Therefore, background exposure to dioxins, furans, and PCBs unrelated to the explosion may have been substantial. As a consequence, previous SWHS studies that considered only TCDD exposure may have underestimated health effects due to total TEQ concentrations.

Exposure assessment for endocrine disruptors: some considerations in the design of studies

In studies designed to evaluate exposure-response relationships in children's development from conception through puberty, multiple factors that affect the generation of meaningful exposure metrics must be considered. These factors include multiple routes of exposure; the timing, frequency, and duration of exposure; need for qualitative and quantitative data; sample collection and storage protocols; and the selection and documentation of analytic methods. The methods for exposure data collection and analysis must be sufficiently robust to accommodate the a priori hypotheses to be tested, as well as hypotheses generated from the data. A number of issues that must be considered in study design are summarized here.

TCDD-mediated alterations in the AhR-dependent pathway in Seveso, Italy, 20 years after the accident

Approximately 20 years after the Seveso, Italy, accident we conducted a population-based study to evaluate the impact of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) exposure on cancer using mechanistically based biomarkers of dioxin response in humans. TCDD toxic effects are mediated by the aryl hydrocarbon receptor (AhR). We studied the AhR-dependent pathway in lymphocytes from 62 subjects randomly sampled from the highest exposed zones and 59 subjects from the surrounding non-contaminated area, frequency matched for age, gender and smoking. To our knowledge, this is the most comprehensive investigation to date designed to evaluate the key genes in the pathway, including AhR, aryl hydrocarbon receptor nuclear translocator, CYP1A1 and CYP1B1 transcripts and CYP1A1-associated 7-ethoxyresorufin O-deethylase (EROD) activity in a population heavily exposed to dioxin. Current lipid-adjusted plasma TCDD concentrations in these subjects ranged from 3.5 to 90 ng/kg (or p.p.t.) and were negatively associated with AhR mRNA in unstimulated peripheral blood mononuclear cells (P = 0.03). When mitogen-induced lymphocytes were cultured with 10 nM TCDD, all AhR-dependent genes were induced 1.2- to 13-fold. In these cells, plasma TCDD was associated with decreased EROD activity. In addition, there was a strong positive correlation between AhR and CYP1A1 expression (P = 0.001) and between AhR and CYP1B1 expression (P = 0.006). CYP1A1 expression was also strongly correlated with EROD activity (P = 0.001). The analysis of the expression of dioxin-inducible genes involved in carcinogenesis may help in determining dose-response relationships for human exposure to dioxin in vivo and in assessing the variability of human response, which may indicate the presence of subjects more susceptible to disease as a result of such exposures.

Uptake and metabolism of hydroxymatairesinol in relation to its anticarcinogenicity in DMBA-induced rat mammary carcinoma model

The chemopreventive effects of hydroxymatairesinol (HMR), a lignan extracted from Norway spruce (Picea abies), on the development of mammary carcinoma induced by 7,12-dimethylbenz[a]anthracene (DMBA) was studied in rats. HMR administered via diet in an average daily dose of 4.7 mg/kg body wt starting before DMBA induction reduced tumor volume and tumor growth, but no significant reduction in tumor multiplicity (number of tumors/rat) was observed. The predominant histological type in the control group was type B (well-differentiated adenocarcinoma, 78%). The proportion of type B tumors decreased to 35% in the HMR group, while the type A (poorly differentiated) and type C (atrophic) tumor proportions increased. Anticarcinogenic effects of dietary HMR (4.7 mg/kg) were also evident when the administration started after DMBA induction and was seen as growth inhibition of established tumors. Dietary HMR supplementation significantly increased serum and urinary enterolactone and HMR concentrations but had no significant effect on the uterine weight, suggesting that HMR or its major metabolite enterolactone did not have an antiestrogenic effect. Further studies are warranted to further clarify and verify HMR action and the associated mechanisms in mammary tumorigenesis.

Serum dioxin concentrations and breast cancer risk in the Seveso Women's Health Study

2,3,7,8-Tetrachlorodibenzo-(italic)p(/italic)-dioxin (TCDD or dioxin), a widespread environmental contaminant, has been shown to disrupt multiple endocrine pathways. The International Agency for Research on Cancer classified TCDD as a known human carcinogen, primarily based on occupational studies of increased mortality from all cancers combined. Using data from the Seveso Women's Health Study (SWHS), we examined the association between individual serum TCDD levels and breast cancer risk in women residing around Seveso, Italy, in 1976, at the time of an industrial explosion that resulted in the highest known population exposure to TCDD. The SWHS cohort comprises 981 women who were infants to 40 years old in 1976, resided in the most contaminated areas at the time of the explosion, and had archived sera that was collected soon after the explosion. For each woman, serum TCDD exposure was measured by high-resolution mass spectrometry. Cancer cases were identified during interview and confirmed by medical record. At interview, 15 women (1.5%) had been diagnosed with breast cancer and serum TCDD levels for cases ranged from 13 to 1,960 ppt. Cox proportional hazards modeling showed that the hazard ratio for breast cancer associated with a 10-fold increase in serum TCDD levels (log(subscript)10(/subscript) TCDD) was significantly increased to 2.1 (95% confidence interval, 1.0-4.6). Covariate-adjusted results were not different. Individual serum TCDD is significantly related with breast cancer incidence among women in the SWHS cohort. Continued follow-up of the cohort will help shed light on the possible role of TCDD in the pathogenesis of breast cancer.

Children's exposure to chlorpyrifos and parathion in an agricultural community in central Washington State

We measured two diethyl organophosphorus (OP) pesticides--chlorpyrifos and parathion--in residences, and their metabolic by-products, in the urine of children 6 years old or younger in a central Washington State agricultural community. Exposures to two dimethyl OP pesticides (azinphos-methyl and phosmet) in this same population have been reported previously. We categorized children by parental occupation and by household proximity to pesticide-treated farmland. Median chlorpyrifos house dust concentrations were highest for the 49 applicator homes (0.4 microg/g), followed by the 12 farm-worker homes (0.3 microg/g) and the 14 nonagricultural reference homes (0.1 microg/g), and were statistically different (p < 0.001); we observed a similar pattern for parathion in house dust. Chlorpyrifos was measurable in the house dust of all homes, whereas we found parathion in only 41% of the homes. Twenty-four percent of the urine samples from study children had measurable 3,5,6-trichloro-2-pyridinol (TCPy) concentrations [limits of quantitation (LOQ) = 8 microg/L], and 7% had measurable 4-nitrophenol concentrations (LOQ = 9 microg/L). Child urinary metabolite concentrations did not differ across parental occupational classifications. Homes in close proximity (200 ft/60 m) to pesticide-treated farmland had higher chlorpyrifos (p = 0.01) and parathion (p = 0.014) house dust concentrations than did homes farther away, but this effect was not reflected in the urinary metabolite data. Use of OP pesticides in the garden was associated with an increase in TCPy concentrations in children's urine. Parathion concentrations in house dust decreased 10-fold from 1992 to 1995, consistent with the discontinued use of this product in the region in the early 1990s.

Emerging areas of research reported during the CDC National Conference on Pfiesteria: from biology to public health

Since its identification in 1996, the marine dinoflagellate Pfiesteria piscicida Steidinger & Burkholder has been the focus of intense scientific inquiry in disciplines ranging from estuarine ecology to epidemiology and from molecular biology to public health. Despite these research efforts, the extent of human exposure and the degree of human illness directly associated with Pfiesteria is still in the process of being defined. Unfortunately, during this same time Pfiesteria has also stimulated media coverage that in some instances jumped ahead of the science to conclude that Pfiesteria presents a widespread threat to human health. Political and economic forces also came into play when the tourism and seafood industries were adversely impacted by rumors of toxin-laden water in estuaries along the east coast of the United States. Amid this climate of evolving science and public concern, Pfiesteria has emerged as a highly controversial public health issue. In October 2000 Centers for Disease Control and Prevention sponsored the National Conference on Pfiesteria: From Biology to Public Health to bring together Pfiesteria researchers from many disparate disciplines. The goal of this meeting was to describe the state of the science and identify directions for future research. In preparation for the conference an expert peer-review panel was commissioned to review the existing literature and identify research gaps; the summary of their review is published in this monograph. During the meeting primary Pfiesteria researchers presented previously unpublished results. The majority of those presentations are included as peer-reviewed articles in this monograph. The discussion portion of the conference focused upon researcher-identified research gaps. This article details the discussion segments of the conference and makes reference to the presentations as it describes emerging areas of Pfiesteria research.

Seveso Women's Health Study: does zone of residence predict individual TCDD exposure?

The compound, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), is produced as an unwanted by-product of various chemical reactions and combustion processes, including the manufacture of chlorinated phenols and derivatives. In animals, TCDD exposure is associated with toxic, carcinogenic, developmental, and reproductive effects. In 1976, a chemical plant explosion in Seveso, Italy, exposed the residents in the surrounding community to the highest exposure to TCDD known in humans. Materials from an aerosol cloud of sodium hydroxide, sodium trichlorophenate and TCDD were deposited over an 18.1 km2 area. As evidence of the significant level of TCDD exposure, numerous animals died and 193 cases of chloracne were reported among residents of the area. Initially, the contaminated area was divided into three major exposure Zones (A, B, R) based on the concentration of TCDD in surface soils. To date, the majority of epidemiologic studies conducted in Seveso have used Zone of residence as a proxy measure of exposure. The purpose of the present study is to validate the use of Zone of residence in Seveso as a proxy measure of exposure against individual serum TCDD measurement, and to determine whether questionnaire information can improve the accuracy of the exposure classification. Using data collected from the Seveso Women's Health Study (SWHS), the first comprehensive epidemiologic study of the reproductive health of women in Seveso, we determined that Zone of residence is a good predictor of individual serum TCDD level, explaining 24% of the variance. Using questionnaire information could have improved prediction of individual exposure levels in Seveso, increasing the percent of the variation in serum TCDD levels explained to 42%.

Serum hormone levels in humans with low serum concentrations of 2,3,7,8-TCDD

We measured current serum hormone and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) concentrations in 37 men who sprayed 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) in the State of Victoria, Australia. TCDD levels were consistently significantly inversely related to prolactin levels in all analyses. In correlation analyses, TCDD levels were also inversely related to triiodothyronine (T3), thyroid-stimulating hormone (TSH), and testosterone levels, and positively associated with glucagon levels. The mean serum TCDD concentration in these sprayers was between 2.6 and 8.1 parts per trillion (ppt). Since such TCDD levels are commonly found in the general population in countries such as the US, the results could suggest that background levels of TCDD in the general population could have an effect on hormone levels. The findings are preliminary and need to be replicated in order to evaluate their full public health significance.

Collecting urine samples from young children using cotton gauze for pesticide studies

To estimate pesticide exposure, urine samples are often needed to analyze pesticide metabolites. However, this is difficult for children wearing diapers because simple and feasible techniques suitable for field collection are not available. The objectives of this study were to test the validity of using cotton gauze pad as a medium for collecting urine samples from young children and to examine the stability of the recoveries for creatinine and pesticide metabolites over 24 h. Urine spiked with a pesticide and four metabolites, 2,4-dichlorophenoxyacetic acid (which is mainly eliminated from urine unchanged), 3-phenoxybenzoic acid (metabolite for synthetic pyrethroids), atrazine mercapturate (metabolite for atrazine), malathion dicarboxylic acid (metabolite for malathion), and 2-isopropyl-4-methyl-6-hydroxypyrimidine (metabolite for diazinon) was added to the gauze pads and kept in jars at 37 degrees C in a water bath. Urine was expressed from the gauze pads immediately and after 1, 2, 4, 8, and 24 h, then analyzed. The recoveries, calculated as the percentage of concentration in expressed urine divided by that of the control urine sample, were within a range of 70-130%. The metabolite and creatinine concentrations did not change with time in either expressed urine samples or controls. The results suggest that cotton gauze pad is a promising candidate for collecting urine samples from young children wearing diapers for studies in which these five urinary pesticide metabolites are to be analyzed.

Seveso Women's Health Study: a study of the effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin on reproductive health

Although reproductive effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) exposure have been reported in numerous investigations of animals, studies of this association in humans are limited. In 1976, an explosion in Seveso, Italy exposed the surrounding population to among the highest levels of TCDD recorded in humans. The relatively pure exposure to TCDD and the ability to quantify individual level TCDD exposure from sera collected in 1976 for the Seveso cohort affords a unique opportunity to evaluate the potential dose-response relationship between TCDD exposure and a spectrum of reproductive endpoints. The Seveso Women's Health Study (SWHS) is the first comprehensive study of the reproductive health of a human population exposed to TCDD. The primary objectives of the study are to investigate the relationship of TCDD and the following endpoints: (1) endometriosis; (2) menstrual cycle characteristics; (3) age at menarche; (4) birth outcomes of pregnancies conceived after 1976; (5) time to conception and clinical infertility; and (6) age at menopause. Included in the SWHS cohort are women who were 0-40 yr old in 1976, who have adequate stored sera collected between 1976 and 1980, and who resided in Zones A or B at the time of the accident. All women were interviewed extensively about their reproductive and pregnancy history and had a blood draw. For an eligible subset of women, a pelvic exam and transvaginal ultrasound were conducted and a menstrual diary was completed. More than 95% of the women were located 20 yr after the accident and roughly 80% of the cohort agreed to participate. Data collection was completed in July 1998, serum TCDD analysis of samples for analysis of endometriosis as a nested case-control study was completed in October 1998, and statistical analysis of these data should be completed in early 1999. Serum samples are now being analyzed in order to relate TCDD levels with the remaining reproductive outcomes.

Body burden levels of dioxin, furans, and PCBs among frequent consumers of Great Lakes sport fish. The Great Lakes Consortium

Dioxins, furans, and polychlorinated biphenyls (PCBs) are toxic, persist in the environment, and bioaccumulate to concentrations that can be harmful to humans. Sport anglers may be exposed to these residues via consumption of contaminated Great Lakes (GL) fish. The Health Departments of five GL states, Wisconsin, Michigan, Ohio, Illinois, and Indiana, formed a consortium to study body burden levels of chemical residues in fish consumers of Lakes Michigan, Huron, and Erie. In Fall 1993, a telephone survey was administered to sport angler households to obtain fish consumption habits and demographics. A blood sample was obtained from a portion of the study subjects. One hundred serum samples were analyzed for 8 dioxin, 10 furan, and 4 coplanar PCB congeners. Multiple linear regression was conducted to assess the predictability of the following covariates: GL sport fish species, age, BMI, gender, years sport fish consumed, and lake. Of the 100 subjects, there were 58 men; 35 consumed sport fish from Lake Michigan, 29 from Lake Huron, and 36 from Lake Erie. The overall average number of GL sport fish meals consumed in the previous 12 months was 43. Lake Erie male and female consumers, on average, ate more GL sport fish, a mean of 57 and 42 meals, respectively, than men and women from the other two lake subgroups. Median total dioxin toxic equivalents (TEq), total furan TEq, and total coplanar PCB TEq were higher among all men than all women (P=0.0001). Lake trout, salmon, age, BMI, and gender were significant regression predictors of log(total coplanar PCBs). Lake trout, age, gender, and lake were significant regression predictors of log(total furans). Age was the only significant predictor of total dioxin levels.

Effects of prenatal and postnatal methylmercury exposure from fish consumption on neurodevelopment: outcomes at 66 months of age in the Seychelles Child Development Study

CONTEXT

Human neurodevelopmental consequences of exposure to methyl-mercury (MeHg) from eating fish remain a question of public health concern.

OBJECTIVE

To study the association between MeHg exposure and the developmental outcomes of children in the Republic of Seychelles at 66 months of age.

DESIGN

A prospective longitudinal cohort study.

PARTICIPANTS

A total of 711 of 779 cohort mother-child pairs initially enrolled in the Seychelles Child Development Study in 1989.

SETTING

The Republic of Seychelles, an archipelago in the Indian Ocean where 85% of the population consumes ocean fish daily.

MAIN OUTCOME MEASURES

Prenatal and postnatal MeHg exposure and 6 age-appropriate neurodevelopmental tests: the McCarthy Scales of Children's Abilities, the Preschool Language Scale, the Woodcock-Johnson Applied Problems and Letter and Word Recognition Tests of Achievement, the Bender Gestalt test, and the Child Behavior Checklist.

RESULTS

The mean maternal hair total mercury level was 6.8 ppm and the mean child hair total mercury level at age 66 months was 6.5 ppm. No adverse outcomes at 66 months were associated with either prenatal or postnatal MeHg exposure.

CONCLUSION

In the population studied, consumption of a diet high in ocean fish appears to pose no threat to developmental outcomes through 66 months of age.

Profiles of Great Lakes critical pollutants: a sentinel analysis of human blood and urine. The Great Lakes Consortium

To determine the contaminants that should be studied further in the subsequent population-based study, a profile of Great Lakes (GL) sport fish contaminant residues were studied in human blood and urine specimens from 32 sport fish consumers from three Great Lakes: Lake Michigan (n = 10), Lake Huron (n = 11), and Lake Erie (n = 11). Serum was analyzed for 8 polychlorinated dioxin congeners, 10 polychlorinated furan congeners, 4 coplanar and 32 other polychlorinated biphenyl (PCB) congeners, and 11 persistent chlorinated pesticides. Whole blood was analyzed for mercury and lead. Urine samples were analyzed for 10 nonpersistent pesticides (or their metabolites) and 5 metals. One individual was excluded from statistical analysis because of an unusual exposure to selected analytes. Overall, the sample (n = 31) consumed, on average, 49 GL sport fish meals per year for a mean of 33 years. On average, the general population in the GL basin consume 6 meals of GL sport fish per year. The mean tissue levels of most persistent, bioaccumulative compounds also found in GL sport fish ranged from less than a twofold increase to that of PCB 126, which was eight times the selected background levels found in the general population. The overall mean total toxic equivalent for dioxins, furans, and coplanar PCBs were greater than selected background levels in the general population (dioxins, 1.8 times; furans, 2.4 times; and coplanar PCBs, 9.6 times). The nonpersistent pesticides and most metals were not identified in unusual concentrations. A contaminant pattern among lake subgroups was evident. Lake Erie sport fish consumers had consistently lower contaminant concentrations than consumers of sport fish from Lake Michigan and Huron. These interlake differences are consistent with contaminant patterns seen in sport fish tissue from the respective lakes; GL sport fish consumption was the most likely explanation for observed contaminant levels among this sample. Frequent consumers of sport fish proved to be effective sentinels for identifying sport fish contaminants of concern. In the larger study to follow, serum samples will be tested for PCBs (congener specific and coplanar), DDE, dioxin, and furans.

Immunologic findings in workers formerly exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin and its congeners

One hundred ninety-two workers in a German pesticide factory who were exposed to polychlorinated dibenzodioxins and -furans (PCDD/PCDF) were investigated for former and present diseases and laboratory changes of the immune system. Moreover, in a subgroup of 29 highly exposed and 28 control persons, proliferation studies were performed. In addition to assays such as blood count, immunoglobulins, serum electrophoresis, monoclonal bands, surface markers, autoantibodies, and lymphocyte proliferation, two new methods, the rise of tetanus antibody concentration after vaccination and the in vitro resistance of lymphocytes to chromate, were used to diagnose the morphologic and functional state of the immune system. There was no stringent correlation of actual PCDD/PCDF concentrations with the occurrence of infections or with one of the immune parameters. In addition, outcomes of the tetanus vaccination and the chromate resistance test were not correlated with PCDD/PCDF. However, the chromate resistance of lymphocytes stimulated by phytohemagglutinin of highly exposed persons was significantly lower than that for the control group. These findings indicate that the function of lymphocytes can be stressed and possibly impaired by high exposure to PCDD/PCDF.

Community Health and Medical Practitioners Scheme: providers evaluate a pilot program of integration of services

OBJECTIVE

To set up and evaluate a pilot scheme integrating salaried community health centre staff and fee-for-service medical practitioner services (CHAMPS).

DESIGN

Preliminary interviews with both groups established the aims, logistics and financial arrangements of the project. The community health centre provided staff and the general practitioners provided premises and administrative services. Follow-up interviews evaluated the scheme and made recommendations.

SETTING

A New South Wales country town, population 24,000, with 25 general practitioners and 23 community health centre professionals.

RESULTS

Six general practitioners and 23 community health professionals determined the aims to be: improved access for patients to community health services; improved liaison between the two groups of providers; and a broadening of services offered at general practice locations. Two dietitians and three mental health workers were rostered for half a day per week in four general practices for six months. The dietitians continued after the project finished, but the mental health workers did not. The five community health staff, five of the general practitioners originally interviewed and six other general practitioner participants cited the major benefits as increased communication between providers and improved access for patients, and the major difficulties as lack of appropriate equipment and organisational logistics.

CONCLUSIONS

The providers believe that the project succeeded in improving access to community health services and liaison between professionals. For future projects they recommended better communication, firmer role delineation and better planning for space and equipment.

Tryptophan contaminants associated with eosinophilia-myalgia syndrome. The Eosinophilia-Myalgia Studies of Oregon, New York and New Mexico

Eosinophilia-myalgia syndrome (EMS) has been linked to ingestion of tryptophan contaminated with 1,1'-ethylidene-bis[L-tryptophan] (EBT), but other contaminants have received little study. The authors identified 101 lots of L-tryptophan that had been consumed either by persons with EMS or by asymptomatic tryptophan users and quantified the amounts of EBT and five other contaminants in each lot. After stratification of case and noncase lots by time of manufacture to adjust for the strong sequential pattern over time among case and noncase lots, higher EBT levels were still associated with a lot's case status, but the association lacked statistical significance (p = 0.120, odds ratio = 1.56, 95% confidence interval 0.758-3.23). While these findings do not rule out the possibility that EBT is the etiologic agent in EMS, they raise the possibility that other chemical contaminants in manufactured tryptophan modify the effects of EBT or that the causal agent of EMS is an entirely distinct compound.

Tumor cell adhesion to endothelial cells: endothelial leukocyte adhesion molecule-1 as an inducible adhesive receptor specific for colon carcinoma cells

Activation of endothelial cells by the two inflammatory mediators interleukin-1 (IL-1) and tumor necrosis factor strongly increases tumor cell adhesion. We describe antibody inhibition studies showing that the endothelial leukocyte adhesion molecule-1 (ELAM-1), a cell-surface glycoprotein selectively expressed by cytokine-activated endothelial cells and responsible for neutrophil adhesion, is the major, if not the only, mediator of colon carcinoma cell adhesion to activated endothelial cells. Among the different tumor cell lines tested, seven colon carcinoma cell lines were sensitive to ELAM-1 antibodies. Adhesion of melanoma, osteosarcoma, and lung, cervix, or kidney carcinoma cell lines to IL-1-treated endothelial cells was not affected by the ELAM-1 antibody. This result suggests that ELAM-1 is selectively recognized by colon carcinoma cells and that adhesion of tumor cells to activated endothelial cells could be mediated by different and specific mechanisms.

Evidence that secondary rat Schwann cells in culture maintain their differentiated phenotype

Schwann cells, on receiving the correct signal, will encircle an axon and wrap it with a myelin sheath. To begin examining some of the mechanisms underlying the process of myelination in vitro, we isolated Schwann cells from the sciatic nerves of neonatal rats and generated large cell populations with cholera toxin. The immunological and biochemical properties of these secondary Schwann cells were characterized after five to seven passages in the absence of axonal contact. These cells continued to express antigens found in both myelinating (P0 and 2',3'-cyclic nucleotide phosphohydrolase) and nonmyelinating cells in vivo (A5E3 and glial fibrillary acidic protein) in addition to the markers common to both types of cells (Ran-1, 217c, S-100, and laminin). Biochemical analyses showed that these cells synthesize the very-long-chain fatty acids (22-26 carbon atoms) found in myelin membranes. Moreover, the enzymes required for the synthesis of myelin glycolipids (including sphingosine acyltransferase, UDP-galactose:ceramide galactosyltransferase, and cerebroside sulfotransferase) were still active, and metabolic labeling studies showed that galactocerebroside and sulfatide were synthesized even though the galactocerebroside pool was insufficient to be detected by immunostaining. Secondary Schwann cells also synthesized four species of myelin basic protein and the major structural glycoprotein in myelin, P0. The pathway necessary for glycosylation of P0 protein remained active, and an analysis of the oligosaccharide chain revealed that approximately 70% was processed to a complex form. In summary, we found that secondary Schwann cells still express most of the immunological markers of differentiated cells and continue to synthesize low levels of myelin components. Therefore, Schwann cells do not dedifferentiate in culture, as previously believed.