The role of sport-fish consumption advisories in mercury risk communication: a 1998-1999 12-state survey of women age 18-45

BACKGROUND

In 2002, in the United States, 48 states issued advisories for sport-fish consumers that included 39 chemical contaminants. The most commonly identified chemical was methyl mercury, which is linked to reproductive and developmental effects. Advisories to reduce consumption of contaminated fish have been issued by states since the early 1970s. Advisories are being integrated to include both sport and commercial fish.

METHODS

As part of a comprehensive risk-communication project, from December 1998 through August 1999 the Wisconsin Division of Public Health and the State of Maine Bureau of Health conducted a 12-state random-digit-dial telephone survey of 3015 women of childbearing age (ages 18-45). The goal was to assess the prevalence of fish consumption, understanding of mercury toxicity, and awareness of state sport-fish consumption advisories for mercury. We gathered information concerning respondents' demographic characteristics, understanding of mercury toxicity, fish consumption during the preceding 12 months, and sport-fish consumption advisory awareness.

RESULTS

The overall survey completion rate was 57% with a Council of American Survey Research Organizations (CASRO)-calculated response rate of 50%. Completion rates varied from 37% in New Jersey to 73% in Minnesota. Fish consumption during the previous 12 months was reported by 87% of respondents (range by state of 82-90%). Nearly 10% of women reported consuming two or more fish-meals per week over the prior 12 months. Twenty-nine percent reported sport-fish consumption during the same time period, with a greater state-to-state variability (14-43%). Most women (71%) were aware of mercury's toxicity to a developing child (87% among those aware of an advisory and 67% among those unaware of an advisory). However, awareness of state advisories was only 20%, ranging by state from 8% to 32%. Women who were older, had more than a high school education, and had a household member with a fishing license were the most informed about mercury and fish-consumption advisories.

CONCLUSIONS

Most women of childbearing age consume commercial fish and a substantial number also consume sport-caught fish. Despite this potential exposure to dietary mercury, most are unfamiliar with their state's mercury fish-consumption advisory. Most women were aware of the most toxic effects of mercury but less informed about mercury and its relationship to types of fish and fish characteristics. Minorities, women over age 30, family incomes above 25,000 US dollars, and those with some collage education were more likely to be consuming two or more fish-meals per week. Until source control and environmental remediation efforts can reduce the environmental burden of mercury below levels of concern, combined sport and commercial fish consumption advisories will remain the primary means of reducing human exposure to methylmercury. Assuring and assessing the effectiveness of such advisories is paramount. Our survey documents that current efforts to inform vulnerable populations are far from optimal.

Oxidative stress inhibits the phagocytosis of apoptotic cells that have externalized phosphatidylserine

The efficient phagocytosis of apoptotic cells by macrophages reduces the potential for an inflammatory response by ensuring that the dying cells are cleared before their intracellular contents are released. Early apoptotic cells are targeted for phagocytosis through the translocation of phosphatidylserine (PS) from the inner to the outer leaflet of the plasma membrane. In this report, we show that the oxidant H(2)O(2) inhibits phagocytosis of apoptotic cells even though the cells express functional PS on their surface. Thus, B lymphoma cells induced to undergo apoptosis by the chemotherapy drug etoposide are efficiently phagocytosed by macrophages in a process that is mediated by PS (inhibitable by PS liposomes). Exposure of the apoptotic cells to H(2)O(2) inhibits phagocytosis even though the cells still express functional PS on their surface. In addition, Jurkat cells and thymocytes induced to undergo apoptosis by H(2)O(2) alone are poorly phagocytosed. Inhibition of phagocytosis by H(2)O(2) cannot be attributed to oxidative inactivation or redistribution of PS on the cell surface. The results indicate that PS externalization is necessary but is not sufficient to target apoptotic cells for phagocytosis. Another phagocytosis recognition factor must therefore exist to facilitate uptake of apoptotic cells, and this factor is sensitive to modification by H(2)O(2).

Use of imported folk remedies and medications in the Wisconsin Hmong community

The Marathon County Health Department and the Wisconsin Division of Public Health evaluated several imported drugs and folk remedies that were being used by 2 Hmong families. These included a powdered blend of folk remedies that had been purchased in California and 5 packets of medication that had been imported from Thailand. The powdered folk remedy contained arsenic sulfide as a principal ingredient. The drug packets contained acetyl aspirin, acetaminophen and chloramphenicol. The purity of these drugs was not assessed, and their dates of manufacture could not be determined. To discourage use of folk remedies and imported drugs, the county health department issued a press release that was published in a Hmong community newsletter. Despite these efforts, many Asian immigrants may continue to use these products.

The effects of PCB exposure and fish consumption on endogenous hormones

Previous studies have suggested that exposure to polychlorinated biphenyls (PCBs) may alter thyroid function, but data on effects of PCB exposure on other endogenous hormones has been lacking. The current study is ancillary to a larger investigation of the effects of Great Lakes fish consumption on PCBs and reproductive function. In the current study we examine associations of PCBs, 1,1-bis (4-chlorophenyl)-2,2-dichloroethene (DDE), and fish consumption with thyroid and steroid hormones in 178 men and PCBs, DDE, and fish consumption with thyroid hormones in 51 women from the original study. Serum PCB level and consumption of Great Lakes fish are associated with significantly lower levels of thyroxine (T(4)) and free thyroxine index (FTI) in women and with significantly lower levels of T(4) in men. Fish consumption, but not PCB level, is significantly and inversely associated with triiodothyronine (T(3)) in men. Results for thyroid-stimulating hormone (TSH) are inconsistent. Among men, there are significant inverse associations of both PCB and fish consumption with sex hormone-binding globulin (SHBG)-bound testosterone, but no association with SHBG or free testosterone. There are no significant overall associations of PCB, DDE, or fish consumption with estrone sulfate, follicle-stimulating hormone, luteinizing hormone, or dehydroepiandrosterone sulfate. The results of this study are consistent with previous studies showing effects of fish consumption and PCB exposure on thyroid hormones and suggest that PCBs may also decrease steroid binding to SHBG. Elucidation of specific mechanisms must await future investigations.

The effects of PCB exposure and fish consumption on endogenous hormones

Previous studies have suggested that exposure to polychlorinated biphenyls (PCBs) may alter thyroid function, but data on effects of PCB exposure on other endogenous hormones has been lacking. The current study is ancillary to a larger investigation of the effects of Great Lakes fish consumption on PCBs and reproductive function. In the current study we examine associations of PCBs, 1,1-bis (4-chlorophenyl)-2,2-dichloroethene (DDE), and fish consumption with thyroid and steroid hormones in 178 men and PCBs, DDE, and fish consumption with thyroid hormones in 51 women from the original study. Serum PCB level and consumption of Great Lakes fish are associated with significantly lower levels of thyroxine (T(4)) and free thyroxine index (FTI) in women and with significantly lower levels of T(4) in men. Fish consumption, but not PCB level, is significantly and inversely associated with triiodothyronine (T(3)) in men. Results for thyroid-stimulating hormone (TSH) are inconsistent. Among men, there are significant inverse associations of both PCB and fish consumption with sex hormone-binding globulin (SHBG)-bound testosterone, but no association with SHBG or free testosterone. There are no significant overall associations of PCB, DDE, or fish consumption with estrone sulfate, follicle-stimulating hormone, luteinizing hormone, or dehydroepiandrosterone sulfate. The results of this study are consistent with previous studies showing effects of fish consumption and PCB exposure on thyroid hormones and suggest that PCBs may also decrease steroid binding to SHBG. Elucidation of specific mechanisms must await future investigations.

Temporal changes in soil properties at an upland Scottish site between 1956 and 1997

The aim of this study was to examine the frequency with which soil samples require to be taken in order to determine significant temporal changes in soil properties. The examination was carried out using data from Glensaugh Research Station in north-east Scotland where podzolic soils were sampled in 1956, 1977 and 1997, and by re-analysis of archived material. Significant differences in chemistry due to storage were detected, particularly decreases in pH of air-dried organic soils. In these cases original data were used for statistical analysis to establish changes between 1956 and 1997. Temporal changes were found for exchangeable Ca and Mg which generally decreased with time throughout the soil profile, whereas exchangeable H increased. Derived data, such as percent base saturation, declined dramatically due to decreases in exchangeable base cations. Similar podzolic soils were sampled at an adjacent Environmental Change Network (ECN) site in 1993. Application of statistical techniques to the ECN soil chemistry data allowed an estimation of the detectable change between any two years. These data along with the rates of temporal change from 1956 to 1997 allowed the calculation of the number of years required for measurable changes to be achieved. These changes and sampling intervals vary among different horizons and chemistries. Although they are site-specific, they do confirm that the current ECN protocols of a 5-year and 20-year sampling would be appropriate in order to detect changes in soil properties over time at this site.

Occupational and adult lead exposure in Wisconsin

Lead is a versatile metal with many industrial applications. It is among the oldest recognized occupational health hazards. Lead poisoning has been a reportable disease in Wisconsin since 1911. Although reportable, it was not until Wisconsin established an Occupational and Environmental Health Epidemiology program in 1979 that modern reporting levels were adopted, physician and laboratory reporting promoted and publicized, and elevated blood lead report tracking initiated. With the federal funding from the National Institute of Occupational Safety and Health (NIOSH), a comprehensive adult blood lead surveillance program was created in 1987. Eleven years of surveillance trend data reveal a Wisconsin success story. Most Wisconsin industries have made substantial strides toward reducing occupational lead exposure. The improvement is reflected in the reduced number of elevated blood lead levels in Wisconsin's adult blood lead surveillance data. However, Wisconsin must remain vigilant as new and re-emerging lead exposures continue to be identified through adult blood lead surveillance. Wisconsin will also need to continue with its occupational lead exposure reduction efforts if it is to achieve the Federal Healthy People 2010 goals and objectives to have no adult blood lead level greater than 25 micrograms/dL.

Radon in Wisconsin

Owners of about 15% to 20% of the homes in Wisconsin have tested their indoor air for the carcinogenic gas radon. Five percent to 10% of homes have year-average main-floor radon levels that exceed the US Environmental Protection Agency (EPA) exposure guideline, and they are found in most regions of the state. Attempting to retroactively seal foundations to keep radon from the ground out of a home is largely ineffective. However, a soil-depressurization radon mitigation system is highly effective for existing houses, and new homes can easily be built radon-resistant. As the number of homeowners obtaining needed repairs increases, significant lung cancer risk reduction is being achieved in a voluntary, non-regulatory setting. In coming years, as radon in community drinking water supplies becomes regulated under the federal 1996 Safe Drinking Water Act, the "multimedia" option of the act may result in additional attention to mitigation of radon in indoor air.

Fish consumption habits and advisory awareness among Fox River anglers

Eating PCB-contaminated fish caught from the Lower Fox River, northeast Wisconsin, has raised concern about the health risk to consumers, especially to children and unborn babies. The fish advisory published by the state of Wisconsin recommends which fish are safe to eat. However, there is reason to believe that many anglers, especially non-English speaking anglers, are not aware of the advisory and the possible health risks of eating contaminated fish. A face-to-face survey administered to 104 anglers fishing along the Fox River indicates that 17% of anglers eat some or all of the fish they catch and that 83% practice "catch and release." Almost all the anglers were not familiar with Wisconsin's fish advisory but had heard of the health risks from their local newspaper and TV. As a follow-up, a fish health advisory brochure specific to the Fox River was developed.

Asthma hospitalizations in Wisconsin: a missed opportunity for prevention

Asthma is the most common chronic disease of children and the third leading cause of preventable hospitalizations in the United States. To assess the impact of this disease on Wisconsin, we examined 1996-1998 state-wide and county-specific asthma hospitalization rates and compared these rates to Wisconsin 1990-1992 rates, national rates, and United States Healthy People 2010 asthma target objectives. Wisconsin's average asthma hospitalization rate has decreased from 13.4/10,000 during 1990-1992 to 12.1/10,000 during 1996-1998. Wisconsin children 0-4 years of age had the highest asthma-related hospitalization rate (38.0/10,000) of all age groups, during 1996-1998. Wisconsin African American residents had an average asthma hospitalization rate 6.6 times higher than whites (58.5 vs. 8.8 per 10,000, respectively) during 1996-1998. Milwaukee County had the highest county-specific asthma hospitalization rate in the state (26.4/10,000). Unless significant reductions are achieved, Wisconsin will not reach the Healthy People 2010 target objectives. Interventions should be directed to preventing asthma hospitalizations, especially among Wisconsin's youth and African American population.

Environmental contaminants in human milk

Environmental contaminants can be stored in the mother's body or can be transiently present from current diet, occupational exposures or personal habits. These chemicals can be transferred prenatally to the developing fetus or postnatally from breast milk to the nursing infant. Exposures through breast milk can be substantial, especially when the mother has significant ongoing exposures or has accumulated an unusually high body burden of persistent chemicals. Several studies demonstrate that organochlorines (OCs) acquired from breast milk elevate a child's body burden for several years. The decline of persistent OC residues in Western countries suggests that these exposures through breast milk will also diminish. Heavy metals such as lead and mercury are also present in milk, but the pharmacokinetics are quite different from OCs. Less persistent environmental agents, including solvents, polycyclic aromatic hydrocarbons, certain pesticides, and nicotine, can also be detected in milk. There is little information on currently used pesticides and other more recently identified environmental agents for which exposures are common today. Epidemiologic research has established that pre- and postnatal exposures to environmental contaminants including lead and OCs are associated with developmental deficits in early childhood. Therefore, characterization of these contaminants in breast milk can add to our knowledge of potential environmental exposures among children.

Wisconsin children at risk for lead poisoning

The 1999 US Government Accounting Agency (GAO) report to Congress documented that among children in the United States, those served by federal health care programs had high rates of lead poisoning but low rates of blood lead testing. To further explore these findings, the Wisconsin Department of Health and Family Services initiated matching the state's blood lead test data file with the Medicaid eligibility file, and with the WIC Program enrollment file. This article examines data analyzed from the matched files for the year 1999. The results of the analysis of Wisconsin data shadowed the national findings contained in the GAO report. About half of the Wisconsin children enrolled in Medicaid and WIC have been screened, the majority of lead poisoned children in Wisconsin receive Medicaid (80%) and WIC (60%) services. Additional data collected by the department on the physical and environmental health of severely lead-poisoned children indicates that lead-coated surfaces and deterioration were identified as the primary source and cause of the poisoning. These findings support the Wisconsin recommendations for blood lead testing of 1 and 2 year olds living in older or renovated housing, and all children enrolled in Medicaid or WIC.

Hazardous ammonia releases in Wisconsin: trends and risk factors for evacuation and injury

OBJECTIVE

To assess trends in hazardous ammonia releases and risk factors for subsequent evacuation and injury.

METHODS

Analysis of the Wisconsin Hazardous Substances Emergency Events Surveillance system data during 1993 through 1998.

RESULTS

Ammonia releases (291) accounted for 13% of all reported chemical releases, but 26% of all releases that led to evacuations. The majority of non-transportation-related ammonia releases are the result of equipment failure or operator error (85.5%). Few ammonia releases are transportation-related (6.5%) or occur during extreme weather (14.4%). Extreme weather is not a risk factor for evacuation or injury following ammonia releases.

CONCLUSIONS

Ammonia releases are frequently the result of equipment failure or operator error and thus preventable. The majority of ammonia releases that lead to evacuation and injury are not the result of transportation accidents or weather factors beyond human control. Prevention efforts that focus on preventive maintenance, and worker training and awareness could reduce the burden of hazardous ammonia releases.

Ozone and particulate matter air pollution in Wisconsin: trends and estimates of health effects

OBJECTIVES

Ozone and particulate matter 10 microns in diameter or less (PM10) are associated with increased risk of morbidity and mortality. This paper will report ozone and PM10 trends in Wisconsin and provide estimates of potentially susceptible populations and adverse health outcomes associated with current levels of these pollutants.

METHODS

Ozone and PM10 monitoring data is provided by Department of Natural Resources (DNR) air monitors. Exposure-response modeling and data, provided by the United States Environmental Protection Agency (US EPA), was used to estimate hospital admissions associated with ozone and PM10 pollution.

RESULTS

Days with high ozone concentrations have become less frequent and the annual PM10 levels have decreased over the 1990s. However, the potentially susceptible population has increased, the number of children who could experience a lung function decrement due to ozone is between 12,978 and 38,653, and high PM10 concentrations are estimated to have resulted in 43 hospital admissions.

CONCLUSION

Despite decreasing ozone and PM10 levels, the burden of respiratory and cardiovascular disease affected by these pollutants remains significant.

Concentration of MHC class II molecules in lipid rafts facilitates antigen presentation

The plasma membranes of eukaryotic cells are not uniform and possess distinct cholesterol- and sphingolipid-rich raft microdomains that are enriched in proteins known to be essential for cellular function. Lipid raft microdomains are important for T cell receptor (TCR)-mediated activation of T cells. However, the importance of lipid rafts on antigen presenting cells (APCs) and their role in major histocompatibility (MHC) class II-restricted antigen presentation has not been examined. MHC class II molecules were found to be constitutively present in plasma membrane lipid rafts in B cells. Disruption of these microdomains dramatically inhibited antigen presentation at limiting concentrations of antigen. The inhibitory effect of raft disruption on antigen presentation could be overcome by loading the APCs with exceptionally high doses of antigen, showing that raft association concentrates MHC class II molecules into microdomains that allow efficient antigen presentation at low ligand densities.

Identification of syntaxin 1A as a novel binding protein for presenilin-1

Mutations in the presenilin 1 gene have been shown to result in Alzheimer's disease. Presenilin 1 is a multi-transmembrane protein with a large hydrophilic loop near the C-terminus. This region is required for known functions of presenilin 1. We have constrained this loop within the active site of the bacterial protein, thioredoxin, to mimic its native conformational state. This hybrid protein was used as bait in a yeast two hybrid screen in an attempt to identify presenilin binding proteins. By this method syntaxin 1A, a synaptic plasma membrane protein, was identified as a novel binding protein for presenilin 1. In vitro experiments confirm the two-hybrid results suggesting that PS1 binds syntaxin under physiological conditions.

A review of water quality concerns in livestock farming areas

Post-war changes in farming systems and especially the move from mixed arable-livestock farming towards greater specialisation, together with the general intensification of food production have had adverse affects on the environment. Livestock systems have largely become separated into pasture-based (cattle and sheep) and indoor systems (pigs and poultry). This paper reviews water quality issues in livestock farming areas of the UK. The increased losses of nutrients, farm effluents (particularly livestock wastes), pesticides such as sheep-dipping chemicals, bacterial and protozoan contamination of soil and water are some of the main concerns regarding water quality degradation. There has been a general uncoupling of nutrient cycles, and problems relating to nutrient loss are either short-term direct losses or long-term, related to accumulated nutrient surpluses. Results from several field studies indicate that a rational use of manure and mineral fertilisers can help reduce the pollution problems arising from livestock farming practices. Several best management practices are suggested for the control of nutrient loss and minimising release of pathogen and sheep-dip chemicals into agricultural runoff.

Phosphorylation of the invariant chain by protein kinase C regulates MHC class II trafficking to antigen-processing compartments

The invariant chain (Ii) plays a critical role in the transport of newly synthesized class II molecules to endosomal Ag-processing compartments. Of the two major isoforms of human Ii, only Ii-p35 is phosphorylated in vivo, and inhibiting Ii phosphorylation inhibits the trafficking of newly synthesized class II molecules to Ag-processing compartments. We now report that a member of the protein kinase C family of serine/threonine kinases is responsible for the constitutive phosphorylation of 50% of the total cellular pool of Ii-p35 in a wide variety of APCs, including B lymphocytes, PBMC, immature dendritic cells, and mature dendritic cells. Stimulation of protein kinase C activity in APCs significantly enhanced the kinetics of degradation of class II-associated Ii in Ag-processing compartments and the binding of antigenic peptides to these class II molecules. In cells expressing an Ii-phosphorylation mutant, trafficking of class II molecules to endosomes was impaired and Ii proteolysis was inhibited, demonstrating a direct effect of Ii phosphorylation on MHC class II trafficking. These results demonstrate that phosphorylation of Ii in APCs alters the kinetics of trafficking of newly synthesized class II molecules to lysosomal Ag-processing compartments.

Public response to elevated nitrate in drinking water wells in Wisconsin

The authors conducted a survey by mail of Wisconsin families who had their well water tested for nitrate to (a) assess their awareness and compliance with the state's health advisories for nitrate, (b) evaluate their reaction(s) to their test results, and (c) compare demographic differences between exposure levels. Owners of contaminated wells (i.e., > 12.9 mg/l nitrate-nitrogen) were more likely to have lived on a farm, had lower annual incomes, and had older and shallower wells than families whose wells were low in nitrate (i.e., < 2.0 mg/l nitrate-nitrogen). Most respondents were aware of the advisories for pregnant women and infants and, in accordance with these advisories, the majority of families with nitrate-contaminated drinking water took no remedial action. Given that many rural families consume nitrate-contaminated water daily, scientists should conduct additional research to determine whether chronic ingestion of nitrate-contaminated water poses a significant health threat to these families.

Wisconsin farmer cancer mortality, 1981 to 1990: selected malignancies

Cancer mortality risks for Wisconsin white male farmers were examined during the years 1981 to 1990. Four malignancies were studied: Non-Hodgkin's lymphoma, melanoma, colon cancer, and rectal cancer. Occupation coded deaths were segmented into farmer and nonfarmer groups and population counts for the groups were estimated from 1980 and 1990 Bureau of the Census data. Standardized mortality ratios (SMRs) were constructed from the ratio of observed farmer deaths and the expected number of farmer deaths. Expected deaths were generated from the underlying statewide nonfarmer rate for the malignancy multiplied into the farmer population at risk. Farmers had significantly lower mortality risks for melanoma (SMR: 0.659; 95% CI: 0.993-0.326) and colon cancer (SMR: 0.763; 95% CI: 0.928-0.599). Farmers also exhibited a nonsignificant decrement for non-Hodgkin's lymphoma (SMR: 0.930; 95% CI: 1.214-0.645). For rectal cancer, farmers experienced a slightly higher but essentially the same risk as nonfarmers (SMR: 1.013; 95% CI: 1.418-0.608)--the SMR was not significant. This study corroborates a number of cancer incidence and mortality investigations demonstrating that farmers generally experience the same or lower mortality risks for these malignancies.

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.

Serum PCB and DDE levels of frequent Great Lakes sport fish consumers-a first look. The Great Lakes Consortium

Great Lakes (GL) sport fish consumption is a potential human exposure route for polychlorinated biphenyls (PCBs) and dichlorodiphenyl dichloroethene (DDE). Because of fish tissue contamination, frequent consumers of Great Lakes sport caught fish (GLSCF) may be at risk for PCB and DDE accumulation. To examine this problem, the Health Departments of Wisconsin, Illinois, Indiana, Ohio, and Michigan formed a health assessment consortium. Participants were contacted by telephone to complete a detailed demographic and fish consumption survey. Frequent and infrequent GLSCF consumers were identified, and a participant subset was then asked to donate blood for PCB and DDE analysis. Analysis of variance (ANOVA) was done to study exposure group mean differences, while correlation and regression analyses were performed to examine relationships between demographic characteristics, GLSCF consumption, PCB, and DDE body burdens. A total of 4206 individuals participated in the study. Of these, 2542 were habitual GLSCF consumers (mean greater than 35 meals/year males; greater than 27 meals/year females), while 1664 did not eat GLSCF. A subset of 538 participants donated blood and included 439 frequent and 99 infrequent GLSCF consumers. PCB levels were significantly higher in the group of GLSCF consumers (geometric mean: 4.8 ppb males, 2.1 ppb females) when compared to their referents (geometric mean: 1.5 ppb males, 0.9 ppb females), while DDE levels were also higher for GLSCF consumers. PCB and DDE body burdens varied by exposure group, gender, and great lake (Michigan, Huron, Erie). PCB and DDE levels were significantly correlated to age, body mass index, and sport fish and Great Lakes sport fish consumption histories. Regression analysis identified years of consuming sport caught fish as the most robust predictor of PCBs (r2=25%), while age was the best predictor of DDE levels (r2=21%). This study corroborated previous findings relating frequent GLSCF consumption to a higher body burden for PCBs and DDE.

The spectrum of respiratory disease associated with exposure to metal working fluids

Occupational respiratory diseases have been reported following exposure to metal working fluids. We report a spectrum of respiratory illnesses occurring in an outbreak in 30 workers of an automobile parts engine manufacturing plant. Workers presented with respiratory complaints and, after clinical and laboratory evaluations, were classified as those having hypersensitivity pneumonitis, occupational asthma, or industrial bronchitis, or those without occupational lung disease. Hypersensitivity pneumonitis affected seven workers, with six exhibiting serum precipitins to Acinetobacter Iwoffii. Occupational asthma and industrial bronchitis affected 12 and six workers, respectively. Oil-mist exposures were below current recommendations. Gram-negative bacteria, but no fungi, Thermophiles, or Legionella, were identified. Although specific agents responsible for each individual case could not be identified, probably both specific sensitizing agents and non-specific irritants from metal working fluids, additives, or contaminants contributed to this spectrum of occupational respiratory illness.

MHC class I molecules are enriched in caveolae but do not enter with simian virus 40

Simian virus 40 (SV40) binds to MHC class I molecules anywhere on the cell surface and then enters through caveolae. The fate of class I molecules after SV40 binding is not known. Sensitivity of 125I-surface-labelled class I molecules to papain cleavage was used to distinguish internalized class I molecules from class I molecules remaining at the cell surface. Whereas the caveolae-enriched membrane microdomain was found to also be enriched for class I molecules, no internalized papain-resistant 125I-surface-labelled class I molecules could be detected at any time in either control cells or in cells preadsorbed with saturating amounts of SV40. Instead, 125I-surface-labelled class I molecules, as well as preadsorbed 125I-labelled anti-class I antibodies, accumulated in the medium, coincident with the turnover of class I molecules at the cell surface. The class I heavy chains that accumulated in the medium were truncated and their release was specifically prevented by the metalloprotease inhibitor 1,10-phenanthroline. Thus, whereas class I molecules mediate SV40 binding, they do not appear to mediate SV40 entry.

Phosphorylation regulates the delivery of MHC class II invariant chain complexes to antigen processing compartments

Transport of newly synthesized MHC class II glycoproteins to endosomal Ag processing compartments is mediated by their association with the invariant chain (Ii). Targeting to these compartments is dependent upon recognition of leucine-based endo. somal/lysosomal targeting motifs in the Ii cytosolic domain. Ii, like many molecules that contain leucine-based endosomal targeting motifs, is phosphorylated in vivo. In this report we demonstrate that the cytosolic domain of the p35 Ii isoform is phosphorylated in class II Ii complexes isolated from human B lymphoblastoid cell lines or freshly obtained PBMC. Mutation of serine residue 6 or 8 prevents phosphorylation of Ii-p35 expressed in HeLa cells. Treatment of B lymphoblastoid cell lines with the serine/threonine kinase inhibitor staurosporine prevented Ii phosphorylation and significantly delayed trafficking of newly synthesized class II Ii complexes to endosomal Ag processing compartments. By contrast, staurosporine had no effect on the rate of transport of class I or class II glycoproteins through the Golgi apparatus and did not inhibit the delivery of the chimeric molecule Tac-DM, to endocytic compartments, suggesting that staurosporine does not nonspecifically inhibit protein transport to the endocytic pathway. These results demonstrate that phosphorylation regulates the efficient targeting of MHC class II Ii complexes to Ag processing compartments and strongly suggest that this effect is mediated by phosphorylation of the MHC class II-associated Ii chain.

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.

Targeting of SNAP-23 and SNAP-25 in polarized epithelial cells

SNAP-23 is the ubiquitously expressed homologue of the neuronal SNAP-25, which functions in synaptic vesicle fusion. We have investigated the subcellular localization of SNAP-23 in polarized epithelial cells. In hepatocyte-derived HepG2 cells and in Madin-Darby canine kidney (MDCK) cells, the majority of SNAP-23 was present at both the basolateral and apical plasma membrane domains with little intracellular localization. This suggests that SNAP-23 does not function in intracellular fusion events but rather as a general plasma membrane t-SNARE. Canine SNAP-23 is efficiently cleaved by the botulinum neurotoxin E, suggesting that it is the toxin-sensitive factor previously found to be involved in plasma membrane fusion in MDCK cells. The localization of SNAP-25 in transfected MDCK cells was studied for comparison and was found to be identical to SNAP-23 with the exception that SNAP-25 was transported to the primary cilia protruding from the apical plasma membrane, which suggests that subtle differences in the targeting signals of both proteins exist. In contrast to its behavior in neurons, the distribution of SNAP-25 in MDCK cells remained unaltered by treatment with dibutyryl cAMP or forskolin, which, however, caused an increased growth of the primary cilia. Finally, we found that SNAP-23/25 and syntaxin 1A, when co-expressed in MDCK cells, do not stably interact with each other but are independently targeted to the plasma membrane and lysosomes, respectively.

Correlations among human blood levels of specific PCB congeners and implications for epidemiologic studies

Specific congeners of PCBs may differ with respect to their human health risks. For epidemiologic studies, however, measuring levels of specific congeners--as compared with estimating the concentration of total PCBs present, may be of limited value if levels of specific congeners are highly correlated. We examined the correlations among levels of specific congeners in three groups: controls from a case-control study of breast cancer in North Carolina and two groups from Wisconsin with exposure to fish from contaminated waters. Levels of specific congeners were, in general, highly correlated (Pearson r > 0.80). However, the level of congener 180, a heptachlorobiphenyl, tended to be less correlated with levels of lower-chlorinated biphenyls. Among the implications of these findings are that measurement of a select group of congeners may yield essentially the same information as measurement of a large panel, and may be more cost efficient.

Correlations among human blood levels of specific PCB congeners and implications for epidemiologic studies

Specific congeners of PCBs may differ with respect to their human health risks. For epidemiologic studies, however, measuring levels of specific congeners--as compared with estimating the concentration of total PCBs present, may be of limited value if levels of specific congeners are highly correlated. We examined the correlations among levels of specific congeners in three groups: controls from a case-control study of breast cancer in North Carolina and two groups from Wisconsin with exposure to fish from contaminated waters. Levels of specific congeners were, in general, highly correlated (Pearson r > 0.80). However, the level of congener 180, a heptachlorobiphenyl, tended to be less correlated with levels of lower-chlorinated biphenyls. Among the implications of these findings are that measurement of a select group of congeners may yield essentially the same information as measurement of a large panel, and may be more cost efficient.

Streamwater nitrate concentrations in six agricultural catchments in Scotland

The concentrations of nitrate-N (NO3-N) in catchment inputs and outputs have been compared and contrasted between 6 farm catchments in Scotland, 3 in the West and 3 in the North-East. Forms of intensive animal farming ranging between beef and dairy cattle, sheep and poultry give different sources for potential NO3-N leakage from the systems. While stream reaches bordered by intensive cereal production give rise to the largest inputs to surface waters, climatic influences result in the more-efficient use of fertilizer- and farm waste-N in the West, and an enhanced potential for N-loss to waters in the cooler North-East, regardless of the N-inputs being considerably lower in the latter region. Although the EC Nitrate Directive limit of 11.3 mg NO3-N 1(-1) was not exceeded, peak values occurring during summer baseflows and autumn soil rewetting were commonly larger than the 'target' maximum concentration of 5.65 mg NO3-N 1-1.

Asthma. The states' challenge

At the national level, asthma is increasingly being recognized as an important public health problem. Because of the significant role of environmental exposure in asthma morbidity, public health agencies have a critical role to play in the surveillance and prevention of the disease. In April 1996, the Council of State and Territorial Epidemiologists, with assistance from the Centers for Disease Control and Prevention, surveyed state and territorial public health departments to determine the status of their asthma surveillance and intervention programs. Of the 51 health departments that responded, only eight reported that they had implemented an asthma control program within the previous 10 years. Reasons cited for not having programs included lack of funds, shortage of personnel, and asthma not being a priority. Most states were unable to assess the burden of asthma because they lack data or face barriers to using existing data. Removing barriers to the use of data is a first step toward defining the scope of the asthma problem.

Bound simian virus 40 translocates to caveolin-enriched membrane domains, and its entry is inhibited by drugs that selectively disrupt caveolae

Simian virus 40 (SV40) entry leading to infection occurred only after the virus was at the cell surface for 1.5 to 2 h. SV40 infectious entry was not sensitive to cytosol acidification, a treatment that blocks endocytosis via clathrin-coated vesicles. Instead, SV40 infectious entry was blocked by treating cells with the phorbol ester PMA or nystatin, which selectively disrupts caveolae. In control experiments, transferrin internalization was sensitive to cytosol acidification but was not sensitive to PMA or nystatin. Also, absorbed transferrin entered cells within minutes. Finally, bound SV40 translocated to caveolin-enriched membrane complexes isolated by a Triton X-100 insolubility protocol. Treatment with nystatin did not impair SV40 binding but did block the partitioning of virus into the caveolin-enriched complexes.

Silicosis among foundry workers. Implication for the need to revise the OSHA standard

To evaluate the risk of pneumoconiosis among workers in a Midwestern automotive foundry, medical records and silica sand exposure data were analyzed for 1,072 current and retired employees with at least 5 years of employment as of June 1991. Approximately half of these employees had worked at the foundry for 20 or more years. Sixty workers were found to have radiographic evidence of pneumoconiosis. Twenty-eight workers had radiographs consistent with silicosis, of which 25 were consistent with simple silicosis and three with progressive massive fibrosis. The prevalence of radiographic changes consistent with silicosis increased with: number of years worked at the foundry (6% for 20-29 years and 12% for 30 or more years); cigarette smoking (12.2% among smokers with high silica exposure vs. 4.4% among never smokers with high silica exposure); work area within the foundry (cleaning room, core room, mold area, core knockout); and quantitative silica exposure (0.3-2.7% of workers at the current Occupational Safety and Health Administration (OSHA) standard and 4.9-9.9% of workers above the OSHA standard). In addition, the odds of developing radiographic changes consistent with silicosis were increased for African Americans (odds ratio = 2.14, 95% confidence interval 0.85-5.60) in comparison with whites. (The risk was similar when silica exposure was equal, but African-American workers on average had greater exposure to silica, despite having a similar duration of work as white workers.) Another eight workers had radiographic evidence of asbestosis, and 24 had pleural plaques. These asbestos-related changes were not associated with increasing exposure to silica but rather were associated with being in the maintenance department and performing repair work. After controlling for cigarette smoking, race, and exposure to silica at another job besides the foundry, the authors found a 1.45 increased risk of developing a radiograph consistent with silicosis after 20 years of work at the current OSHA standard, and a 2.10 increased risk after 40 years of work at the current OSHA standard. On the basis of these findings, the authors recommend maintaining silica air levels no higher than the exposure level of 0.05 mg/m3 recommended by the National Institute for Occupational Safety and Health.

Extracellular simian virus 40 induces an ERK/MAP kinase-independent signalling pathway that activates primary response genes and promotes virus entry

Simian virus 40 (SV40) binding to growth-arrested cells activated an intracellular signalling pathway that induced the up-regulation of the primary response genes c-myc, c-jun and c-sis within 30 min and of JE within 90 min. The up-regulation of the primary response genes occurred in the presence of cycloheximide and when UV-inactivated SV40 was adsorbed to cells. SV40 binding did not activate Raf or mitogen-activated protein kinase (MAP/ERK1), or mobilize intracellular Ca2+. The SV40-induced up-regulation of c-myc and c-jun was blocked by the tyrosine kinase inhibitor, genistein, and by the protein kinase C (PKC) inhibitor, calphostin C, but not by expression of the MAP kinase-specific phosphatase, MKP-1. These results suggest that the SV40-induced signalling pathway includes the activities of a tyrosine kinase and a Ca(2+)-independent isoform of PKC, but not of Raf or MAP kinase. Finally, SV40 infectious entry into cells was specifically and reversibly blocked by genistein.

Surveillance in environmental public health: issues, systems, and sources

This article describes environmental public health surveillance and proposes a framework to enhance its practice in the United States. Special issues for surveillance in environmental public health are examined, and examples of existing systems useful for environmental public health practice are provided. Current and projected surveillance needs, as well as potential sources of data, are examined. The proposed framework for conducting environmental public health surveillance involves data from three points in the process by which an agent in the environment produces an adverse outcome in a host: hazards, exposures, and outcomes. Environmental health practitioners should build on efforts in other fields (e.g., infectious diseases and occupational health) to establish priorities in the surveillance of health conditions associated with exposure to environmental toxicants. For specific surveillance programs, existing data systems, as well as data gaps, should be identified. Coordinated surveillance systems can facilitate public health efforts to prevent and control disease, injury, and disability related to the interaction between people and their environment.

Imported seabass as a source of mercury exposure: a Wisconsin case study

The Wisconsin Division of Health investigated mercury exposure in a 40-year-old man, his 42-year-old wife, and their 2.5-year-old son. At the time of our investigation, these individuals had blood mercury levels ranging from 37 to 58 micrograms/L (normal < 5 micrograms/L) and hair samples from the adults contained 10-12 micrograms mercury/g dry weight. A personal interview and home inspection failed to identify any occupational or household sources of mercury exposure. The family's diet included three to four fish meals per week. The fish was purchased from a local market and included Lake Superior whitefish, Lake Superior trout, farm-raised trout and salmon, and imported seabass. Analysis of these fish found that only one species, the imported seabass, contained significant mercury levels. Two samples of the seabass obtained from the vendor on different days contained mercury concentrations of 0.5 and 0.7 mg/kg. Based on consumption estimates, the average daily mercury intakes for these individuals ranged from 0.5 to 0.8 micrograms/kg body weight. Six months after the family stopped consuming the seabass, blood mercury levels in this man and woman were 5 and 3 micrograms/L, respectively. Analysis of sequential blood samples confirmed that mercury elimination followed first-order kinetics with a half-life of approximately 60 days.

Osteosarcoma, seasonality, and environmental factors in Wisconsin, 1979-1989

Proxy exposure measures and readily available data from the Wisconsin Cancer Reporting System were used to contrast 167 osteosarcoma cases with 989 frequency-matched cancer referents reported during 1979-1989. Differences in potential exposure to water-borne radiation and fluoridated drinking water, population size for the listed place of residence, and seasonality were assessed. An association was found between osteosarcoma and residence in a population of less than 9,000 (odds ratio = 1.6, 95% confidence interval = 1.1-2.4). In addition, an association between month of birth (May through July versus other months of birth) and osteosarcoma among individuals who were less than 25 y of age (odds ratio = 1.9, 95% confidence interval = 1.1-3.4). Overall, no association was found between potential exposure to fluoridated drinking water and osteosarcoma (odds ratio = 1.0, 95% confidence interval = 0.6-1.5). The association between osteosarcoma and water-borne radiation was weak and was not significant statistically (odds ratio = 1.5, 95% confidence interval = 0.8-2.8).

Trends in the surgical treatment of prostate cancer in Wisconsin, 1989-1991

BACKGROUND

Radical prostatectomy (removal of the prostate gland and seminal vesicles) is usually considered a definitive treatment for localized prostate cancer. Although a sharp increase and wide geographic variation in radical prostatectomy rates have been recently documented, the reasons for this increase and the factors that make men diagnosed with the disease more likely to be treated surgically are not well known.

PURPOSE

Our purpose was to examine trends in the use of surgical treatment for prostate cancer, as well as the factors associated with the choice of surgical treatment and how these factors changed in Wisconsin in the period 1989 through 1991.

METHODS

We carried out a population-based cohort study. A cohort of Wisconsin men diagnosed from 1989 through 1991 with prostate cancer was identified through the Wisconsin cancer reporting system. To determine which men diagnosed with prostate cancer were treated with surgery, we linked prostate cancer records to the Wisconsin hospital discharge database. The outcome measured was radical prostatectomy within 6 months from the date of the diagnosis of prostate cancer.

RESULTS

The yearly number of prostate cancer cases reported from 1989 through 1991 rose 33%, from 2468 to 3278. During the same period, the yearly number of radical prostatectomies rose 226%, from 283 to 922. Patients diagnosed in 1991 were twice as likely to have surgery as those diagnosed in 1989, the proportion of cases receiving surgical treatment rising from 12% to 25%. Patients who were white, less than 65 years of age, had a cancer reported to be at regional stage, and who were first reported by large hospitals were more likely to be treated surgically.

CONCLUSIONS

The use of surgery to treat prostate cancer has increased dramatically in Wisconsin, doubling in a 3-year period, despite the fact that studies have not shown surgery to be more effective than other options for many patients. The increase observed in the rate of surgery was about the same across age, race, stage at diagnosis, and hospital size. The reasons for this increase are probably multifactorial.

IMPLICATIONS

Risks, costs, and benefits of surgical treatment should be carefully compared with those of alternative management approaches. Patients should be enabled to make an informed decision, based on the current best evidence, on the treatment option they prefer.

Behavioral risk factors of Chippewa Indians living on Wisconsin reservations

Behavioral risk factors and chronic disease death rates vary markedly among the numerous American Indian tribes. Local data on prevalence of risk factors are important in determining effective community-based interventions. The authors conducted an in-person survey to ascertain the prevalence of behavioral risk factors among members of the Chippewa tribe living on reservations in Wisconsin. A total of 465 Chippewa adults were randomly selected from tribal registries and invited to participate in the study. Of these, 175 (38 percent) participated. To characterize nonrespondents, 75 nonrespondents were randomly selected and aggressively followed up. The authors compared their results with data from the 1989 Wisconsin Behavioral Risk Factor Surveillance System. Chippewa respondents reported high levels of obesity and tobacco use. No significant differences existed between the original survey and followback of nonrespondents. Compared with respondents who had telephones, those without telephones were significantly more likely to be unemployed, to be a current smoker or drinker, and to report nonuse of seatbelts. Compared with the general Wisconsin population, Chippewa adults appear to have higher prevalences of several chronic disease and injury risk factors. The original survey methodology, despite the low response rate, appeared to give a more accurate (less biased) estimate of risk factor prevalences than would have been achieved by a telephone survey.

Fish consumption patterns and blood mercury levels in Wisconsin Chippewa Indians

Methylmercury is a known neurotoxin at high blood levels (> 400 micrograms/l) and is thought to cause neurologic symptoms at substantially lower levels in susceptible adults and infants. Given that levels of methylmercury in fish in northern Wisconsin lakes can be high (> 1 ppm, FDA standard) and Chippewa Indians take large amounts of fish from these lakes, the extent of their exposure to methylmercury was investigated. Using tribal-maintained registries, 465 Chippewa adults living on reservation were selected randomly and were invited to participate; 175 (38%) participated in the study. In an effort to characterize nonrespondents, 75 nonrespondents were selected randomly and were followed up aggressively. An additional 152 volunteers who were selected nonrandomly also participated in the study. Subjects completed a questionnaire about fish consumption patterns and had blood drawn for mercury determination. Sixty-four persons (20%) had blood mercury levels in excess of 5 micrograms/l (i.e., upper limit of normal in nonexposed populations); the highest level found was 33 micrograms/l. Fish consumption was higher in males and the unemployed. Blood mercury levels were highly associated with recent walleye consumption (p = .001). Methylmercury levels in some Wisconsin Chippewa were found to be elevated, but were below the levels associated with adverse health effects. We recommend a continuation of efforts to limit exposures in this high-risk population.

Silicosis surveillance--Michigan, New Jersey, Ohio, and Wisconsin, 1987-1990

PROBLEM/CONDITION

Improved surveillance for silicosis is needed to target interventions to prevent this occupational lung disease caused by the inhalation of crystalline silica dust.

REPORTING PERIOD COVERED

1987-1990.

DESCRIPTION OF SYSTEMS

State-based silicosis surveillance and intervention programs have been developed in Michigan, New Jersey, Ohio, and Wisconsin as part of the Sentinel Event Notification System for Occupational Risks (SENSOR) Program, initiated in 1987 by the National Institute for Occupational Safety and Health (NIOSH).

RESULTS

From 1987 through 1990, the SENSOR program confirmed a total of 430 cases of silicosis reported from these four states. Overall, approximately 60% of these cases were in workers employed in primary metal industries, although the types of industries in which cases occurred varied by state. Some cases were attributable to relatively recent exposure, including new cases in seven persons first exposed since 1980 in New Jersey. Silicosis case reports have prompted measurement of respirable silica concentrations at 25 Michigan work sites, and 14 (56%) of these sites were found to have levels that exceeded the legally permissible exposure level.

INTERPRETATION

The silicosis surveillance and intervention strategies piloted by state health departments in the NIOSH-funded SENSOR Program have demonstrated the feasibility and effectiveness of identifying specific silica-using work sites that need preventive intervention.

ACTIONS TAKEN

On the basis of initial experience in these four states, NIOSH developed guidelines for state-based silicosis surveillance and awarded SENSOR cooperative agreements to three additional states where the applicability of these surveillance methods will be further evaluated.