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Background Afghan refugee children resettled in Washington State have the highest prevalence of elevated blood lead levels (BLLs) of any other refugee or immigrant population. Resettled families brought several lead-containing items with them from Afghanistan, including aluminum cookpots. Objectives To evaluate the potential contribution of lead-containing cookpots to elevated BLLs in Afghan children and determine whether safer alternative cookware is available. Methods We screened 40 aluminum cookpots for lead content using an X-ray fluorescence (XRF) analyzer and used a leachate method to estimate the amount of lead that migrates into food. We also tested five stainless steel cookpots to determine whether they would be safer alternatives. Results Many aluminum cookpots contained lead in excess of 100 parts per million (ppm), with a highest detected concentration of 66,374 ppm. Many also leached sufficient lead under simulated cooking and storage conditions to exceed recommended dietary limits. One pressure cooker leached sufficient lead to exceed the childhood limit by 650-fold. In contrast, stainless steel cookpots leached much lower levels of lead. Significance Aluminum cookpots used by refugee families are likely associated with elevated BLLs in local Afghan children. However, this investigation revealed that other U.S. residents, including adults and children, are also at risk of poisoning by lead and other toxic metals from some imported aluminum cookpots. Impact Statement Some aluminum cookware brought from Afghanistan by resettled families as well as cookpots available for purchase in the United States represent a previously unrecognized source of lead exposure.

We evaluated two types of automotive basecoats used in automotive refinishing (i.e., in auto body shops): waterborne and solventborne. The primary tool we used for this evaluation was the Alternatives Assessment Guide (version 1.0) developed by the Interstate Chemicals Clearinghouse (IC2). The term "solventborne," as used in this article, refers to products that contain relatively high concentrations of volatile organic compounds (referred to as "high-volatile organic compound [VOC] basecoats" in the industry). These products are distinct from the "low-VOC" solventborne products used widely in California and elsewhere. From a health and environmental hazard perspective, our evaluation found that waterborne basecoats contained fewer hazardous ingredients and at lower concentrations than their solventborne counterparts. Automotive painters who spray-painted vehicles with waterborne products experienced significantly lower exposures to several harmful solvents. Waterborne products are readily available and offer advantages with regard to social impacts. Some of these advantages include lower worker and community exposure to VOCs, reduced VOC release and smog formation, and reduced potential for generation of and exposure to hazardous waste. Based on our assessment in auto body shops, we consider waterborne basecoats to be safer alternatives from both a human health and environmental perspective. Integr Environ Assess Manag 2022;18:1101-1113. Published 2021. This article is a U.S. Government work and is in the public domain in the USA.

Perchloroethylene (PERC) is the most common solvent used for dry cleaning in the United States. PERC is a reproductive toxicant, neurotoxicant, potential human carcinogen, and a persistent environmental pollutant. The Environmental Protection Agency is evaluating PERC under the Frank R. Lautenberg Chemical Safety for the 21st Century Act, which amended the Toxic Substances Control Act (amended TSCA), and has mandated that PERC dry cleaning machines be removed from residential buildings. Some local and state programs are also requiring or facilitating transitions to alternative cleaning technologies. However, the potential for these alternatives to harm human health and the environment is not well-understood. This review describes the issues surrounding the use of PERC and alternative solvents for dry cleaning while highlighting the lessons learned from a local government program that transitioned PERC dry cleaners to the safest current alternative: professional wet cleaning. Implications for future public health research and policy are discussed: (1) we must move away from PERC, (2) any transition must account for the economic instability and cultural aspects of the people who work in the industry, (3) legacy contamination must be addressed even after safer alternatives are adopted, and (4) evaluations of PERC alternatives are needed to determine their implications for the long-term health and sustainability of the people who work in the industry.

We investigated the utility of 1,6-hexamethylene diamine (HDA) hemoglobin adducts as biomarkers of exposure to 1,6-hexamethylene diisocyanate (HDI) monomer. Blood samples from 15 spray painters applying HDI-containing paint were analyzed for hemoglobin HDA (HDA-Hb) and N-acetyl-1,6-hexamethylene diamine (monoacetyl-HDA-Hb) by GC-MS. HDA-Hb was detected in the majority of workers (≤1.2-37 ng/g Hb), whereas monoacetyl-HDA-Hb was detected in one worker (0.06 ng/g Hb). The stronger, positive association between HDA-Hb and cumulative HDI exposure (r(2) = 0.3, p 0.06) than same day exposure (p ≥ 0.13) indicates long-term elimination kinetics for HDA-Hb adducts. This association demonstrates the suitability of HDA-Hb adducts for further validation as a biomarker of HDI exposure.

This study was to critically compared 13 different air samplers for their ability to monitor air exposures to monomeric and polymeric 1,6-hexamethylene diisocyanate (HDI) in the automotive refinishing industry. Using both fast- and slow-drying clearcoat, we tested the following types of samplers: single- and dual-stage 37-mm polypropylene (PP) and polystyrene (PS) samplers (open- and closed-face), IOM (with plastic and stainless steel inserts), OSHA42, IsoChek, and WA-DOSH samplers. Midget impingers with frit were used as reference samplers. We observed the PP, PS, and IOM samplers to measure greater levels of HDI monomer and biuret when a fast-drying clearcoat was applied compared with a slow-drying clearcoat. When a slow-drying clearcoat was applied, the open-face PP and PS samplers measured significantly more monomeric and polymeric HDI (2-fold; p0.003) than the closed-face PP and PS samplers. We determined that significantly more monomeric and polymeric HDI were measured by impingers (1.3-1.9-fold) compared with single-stage PP/PS (N = 59), dual-stage PP/PS (N = 59), or IOM (N = 24) samplers. However, when stratified by cassette characteristics, the open-face single-stage PP and PS samplers performed equally to the impingers for HDI monomer when a fast-drying clearcoat was applied, and for all analytes when a slow-drying clearcoat was applied. Significantly higher HDI monomer concentrations (1.2-3.1-fold; p = 0.001) were measured with OSHA42 compared with the impinger. The IsoChek did not detect HDI monomer, and of the three samplers analyzed by laboratories other than UNC (i.e., OSHA42, IsoChek, and WA-DOSH), the WA-DOSH was in the best agreement with the impingers. The influence of clearcoat drying time on the sampler's ability to measure monomeric and polymeric HDI emphasizes the importance of the speciation of diisocyanates in chemical analysis and the careful consideration for the selection of the air sampler to be used when measuring exposures during automotive spray painting.

Although urinary 1,6-hexamethylene diamine (HDA) is a useful biomarker of exposure to 1,6-hexamethylene diisocyanate (HDI), a large degree of unexplained intra- and inter-individual variability exists between estimated HDI exposure and urine HDA levels. We investigated the effect of individual and workplace factors on urine HDA levels using quantitative dermal and inhalation exposure data derived from a survey of automotive spray painters exposed to HDI. Painters' dermal and breathing-zone HDI-exposures were monitored over an entire workday for up to three separate workdays, spaced approximately one month apart. One urine sample was collected before the start of work with HDI-containing paints, and multiple samples were collected throughout the workday. Using mixed effects multiple linear regression modeling, coverall use resulted in significantly lower HDA levels (p = 0.12), and weekday contributed to significant variability in HDA levels (p = 0.056). We also investigated differences in urine HDA levels stratified by dichotomous and classification covariates using analysis of variance. Use of coveralls (p = 0.05), respirator type worn (p = 0.06), smoker status (p = 0.12), paint-booth type (p = 0.02), and more than one painter at the shop (p = 0.10) were all found to significantly affect urine HDA levels adjusted for creatinine concentration. Coverall use remained significant (p = 0.10), even after adjusting for respirator type. These results indicate that the variation in urine HDA level is mainly due to workplace factors and that appropriate dermal and inhalation protection is required to prevent HDI exposure.

The dry cleaning industry is moving away from using perchloroethylene. Occupational exposures to two alternative dry cleaning solvents, butylal and high-flashpoint hydrocarbons, have not been well characterized. We evaluated four dry cleaning shops that used these alternative solvents. The shops were staffed by Korean- and Cantonese-speaking owners, and Korean-, Cantonese-, and Spanish-speaking employees. Because most workers had limited English proficiency we used language services in our evaluations. In two shops we collected personal and area air samples for butylal. We also collected air samples for formaldehyde and butanol, potential hydrolysis products of butylal. Because there are no occupational exposure limits for butylal, we assessed employee health risks using control banding tools. In the remaining two shops we collected personal and area air samples for high-flashpoint hydrocarbon solvents. In all shops the highest personal airborne exposures occurred when workers loaded and unloaded the dry cleaning machines and pressed dry cleaned fabrics. The air concentrations of formaldehyde and butanol in the butylal shops were well below occupational exposure limits. Likewise, the air concentrations of high-flashpoint hydrocarbons were also well below occupational exposure limits. However, we saw potential skin exposures to these chemicals. We provided recommendations on appropriate work practices and the selection and use of personal protective equipment. These recommendations were consistent with those derived using control banding tools for butylal. However, there is insufficient toxicological and health information to determine the safety of butylal in occupational settings. Independent evaluation of the toxicological properties of these alternative dry cleaning solvents, especially butylal, is urgently needed.

In the study reported here, the effect of character size on the reading rates of adults with normal and low vision was measured using both relative-size magnification (by which the print size is increased) and relative-distance magnification (by which the reading distance is decreased with appropriate optical correction). With relative-distance magnification, the reading rates of the subjects with normal vision were slower at close distances, but the results were small and inconsistent. For the subjects with low vision, the magnification method did not affect their reading rates.

Workers in the dry cleaning industry are exposed to a variety of harmful solvents, and poor work practices can result in extensive environmental contamination. Of particular concern is perchloroethylene (PERC), which is the most commonly used cleaning solvent. This chlorinated hydrocarbon is a pervasive environmental contaminant and a probable human carcinogen. PERC is also a neurotoxin and is toxic to the liver and kidneys. The study described here was comprised of key informant interviews, site visits, and a countywide business survey. The 64% response rate to the survey suggests that the results are likely representative of King County's dry cleaning industry. Dry cleaning was determined to be dominated by small, Korean-owned, family-run businesses. Although the use of PERC as the primary dry cleaning agent has decreased in recent years, this solvent is still used by the majority of businesses. This industry would benefit from regulatory intervention in concert with an educational campaign and enhanced technical and financial assistance. For any intervention to be effective, however, it must account for the unique financial and demographic characteristics of this industry.

Isocyanate exposure was evaluated in 33 spray painters from 25 Washington State autobody shops. Personal breathing zone samples (n = 228) were analyzed for isophorone diisocyanate (IPDI) monomer, 1,6-hexamethylene diisocyanate (HDI) monomer, IPDI polyisocyanate, and three polyisocyanate forms of HDI. The objective was to describe exposures to isocyanates while spray painting, compare them with short-term exposure limits (STELs), and describe the isocyanate composition in the samples. The composition of polyisocyanates (IPDI and HDI) in the samples varied greatly, with maximum amounts ranging from up to 58% for HDI biuret to 96% for HDI isocyanurate. There was a significant inverse relationship between the percentage composition of HDI isocyanurate to IPDI and to HDI uretdione. Two 15-min STELs were compared: (1) Oregon's Occupational Safety and Health Administration (OR-OSHA) STEL of 1000 μg/m(3) for HDI polyisocyanate, and (2) the United Kingdom's Health and Safety Executive (UK-HSE) STEL of 70 μg NCO/m(3) for all isocyanates. Eighty percent of samples containing HDI polyisocyanate exceeded the OR-OSHA STEL while 98% of samples exceeded the UK-HSE STEL. The majority of painters (67%) wore half-face air-purifying respirators while spray painting. Using the OR-OSHA and the UK-HSE STELs as benchmarks, 21% and 67% of painters, respectively, had at least one exposure that exceeded the respirator's OSHA-assigned protection factor. A critical review of the STELs revealed the following limitations: (1) the OR-OSHA STEL does not include all polyisocyanates, and (2) the UK-HSE STEL is derived from monomeric isocyanates, whereas the species present in typical spray coatings are polyisocyanates. In conclusion, the variable mixtures of isocyanates used by autobody painters suggest that an occupational exposure limit is required that includes all polyisocyanates. Despite the limitations of the STELs, we determined that a respirator with an assigned protection factor of 25 or greater is required to protect against isocyanate exposures during spray painting. Consequently, half-face air-purifying respirators, which are most commonly used and have an assigned protection factor of 10, do not afford adequate respiratory protection.

Methyl mercury (MeHg) may interfere with cell cycle progression in a number of ways, most notably through an inhibition of protein synthesis or through effects on mitotic spindle performance; both mechanisms have experimental support. Results from investigations into the effects of MeHg exposure on cell cycle progression in a primary fetal rat CNS culture are presented here. Colchicine was also investigated because it is a well-characterized mitotic inhibitor. Flow cytometric DNA content analysis was utilized to determine the cell cycle distribution histograms of control and treated cultures. In addition, a flow cytometric technique which involves the incorporation of 5-bromo-2′-deoxyuridine into newly synthesized DNA was used to discriminate between successive cell cycles. Exposure of the CNS cell cultures to MeHg (2 and 4 μM) over a period of 0-48 hr led to a G 2 /M-phase inhibition as determined by flow cytometric DNA content analysis. Whereas exposure to 2 μM MeHg resulted in G 2 /M-phase inhibition, an analysis of cell cycle progression demonstrated an inhibition of cell cycling through any phase following exposure to 4 μM MeHg; these effects occurred in the first round of cell division following plating. Exposure to colchicine (25 nM) resulted in a G 2 /M-phase arrest similar to that observed with MeHg (2 μM). However, a comparison of the cytotoxicity patterns between MeHg-treated and colchicine-treated cultures suggests that MeHg-induced cytotoxicity cannot be solely ascribed to G 2 /M-phase arrest, since at equivalent levels of G 2 /M-phase arrest, MeHg was more cytotoxic than colchicine. These results are consistent with the hypothesis that microtubules, and the mitotic spindle, are especially sensitive to MeHg exposure.

Substantial exposure to isocyanates may occur during spray painting in autobody shops, yet information is lacking on the efficacy of the protective clothing used during spray painting. We investigated the personal and workplace factors associated with painters' dermal protection use during a large-scale exposure assessment study. Survey data indicated that 69% of painters always used gloves, with latex gloves (47%) and nitrile gloves (34%) used most frequently. Among latex glove users, 53% used thin latex (0.05-0.13 mm), 6% used medium latex (0.15-0.20 mm), and 12% used thick latex (0.20 mm). Among nitrile glove users, 27% used thin nitrile and 45% used medium nitrile. Sixty-three percent of painters always used coveralls, 44% preferring one particular brand. Although overspray presents an opportunity for dermal exposure to the neck and face, only 19% of painters protected these areas with personal protective equipment. Painters who always used coveralls were more likely to use gloves (odds ratio = 7.9, p = 0.061). Painters who reported ever having smoked cigarettes used gloves (p = 0.05) and coveralls (p = 0.04) more frequently. Painters who sprayed more than 34 clear coat jobs per month used coveralls most frequently (p = 0.038). Exact logistic regressions along with random sample calculations indicated that the survey results were independent of the shops. Because of the small sample size in this study, future research is warranted to corroborate these results. Studying the effectiveness of gloves and coveralls against polyurethane paints and understanding the underlying motivators and preferences for painters and business owners is needed for the development of best practices for the selection and use of dermal protection.

Micromass cultures of rat embryonic midbrain cells were characterized with regard to the immunolocalization of neuronal and cytoskeletal markers. Cells taken from gestational day-12 embryos and cultured for 5 days in vitro comprise at least two morphologically distinct cells types: fibroblast-like cells and neurons. Antibodies to the following markers yielded preferential staining of neuronal cells: A2B5 (GQ ganglioside), gamma-aminobutyric acid (GABA), microtubule-associated protein 2 (MAP2), MAP5, neuron-specific enolase (NSE), neural cell adhesion molecule (N-CAM), and tau. Antibodies to beta-tubulin, c-neu, MAP1, and neurofilament (NF-H) stained both neuronal and fibroblast-like cells. Antibodies to glial fibrillary acidic protein (GFAP) and vimentin failed to immunoreact with any cells in day-5 CNS cultures. SDS-PAGE and Western analysis were employed to determine the specificity of the antibodies and determine the electrophoretic profiles of the markers. We conclude that the pattern of neuronal differentiation in CNS micromass cultures exhibits certain similarities to that observed in vivo. In addition, certain markers identified in this study may be of potential utility as (1) biomarkers of chemically-induced developmental neurotoxicity, and (2) indicators of differential toxicity toward the diverse cell types that comprise the mammalian central nervous system.

We have applied research on the visual psychophysics of reading to low vision assessment. Research on different aspects of the reading process found that reading rate rather than reading comprehension is more sensitive to variations in a subject's visual functioning or the stimulus properties of print. The research identified four different visual factors that significantly affect reading rate: (1) acuity reserve [print size relative to acuity threshold], (2) contrast reserve [print contrast relative to contrast threshold], (3) field of view [number of letters visible], and (4) in cases of maculopathy, central scotoma size. Our research indicates that fluent reading rates can be attained with a restricted field of view, as little as four characters. However, attainment of fluent reading levels requires that print size and contrast should be several times threshold and the diameter of a central scotoma should be less than 22 degrees. Although important clinical studies are lacking, we derived specific visual requirements for different reading rates from published experimental research to provide a starting point and to illustrate how visual requirements could be derived, even with poor correlations. Research has made significant progress toward the development of a comprehensive low vision assessment that will allow the practitioner to identify visual impediments to reading, other than reduced visual acuity. Having more fully characterized a visual impairment, the practitioner may tailor devices or interventions to the individual's needs and capabilities.

Objectives: Design, construct, and characterize an apparatus to evaluate dermal protective clothing for resistance to polymerizing materials. Specifically, we evaluated the permeation of the most common glove material used in automotive collision repair (0.10‐0.13 mm or 4‐ 5 mil latex) with representative isocyanate-containing clear coats. Our ultimate goal is to make informed recommendations on dermal protective materials to prevent isocyanate exposures and reduce the likelihood of occupational illness in automotive collision repair and other industries. Methods: A novel permeation panel was developed to assess dermal protective clothing. With this apparatus, up to eight test materials may be evaluated under typical-spray application conditions. Solid collection media comprised of 1-(2-pyridyl)-piperazine (2-PP)-coated fiberglass filters or colorimetric SWYPE pads were placed behind test materials to capture permeants. The 2-PP-coated filters were subsequently analyzed using a modified OSHA42/ PV2034 method. Color change in the SWYPEs provided an immediate field estimate of breakthrough time. In addition, Teflonfilters were mounted proximal to the permeation cells to measure the mass of clear coat applied to the panel and to evaluate loading homogeneity. This study evaluated the permeation of isocyanates through 0.10‐0.13 mm latex glove material at a fixed time (30 min post-spraying) and over a time course (6‐91 min post-spraying). Results: Monomers 1,6-hexamethylene diisocyanate (HDI) and isophorone diisocyanate (IPDI) permeated through (0.10‐0.13 mm) latex glove material under typical glove use conditions (30 min). The latex glove material exhibited immediate breakthrough, with a permeation rate of 2.9 ng min 21 cm 22 . The oligomeric forms of HDI and IPDI did not permeate the latex glove material. The spray application at 71 6 5F was fairly homogeneous (33.7 6 8 mg weight of dry clear coat per 5 cm 2 ). Conclusions: The permeation panel is a viable method to assess dermal protective clothing performance against polymerizing materials. Thin (0.10‐0.13 mm) latex gloves were determined to be ineffective barriers to the isocyanates commonly found in clear coats. Because this type of glove is used frequently in auto body shops, the potential for isocyanate exposure is of concern. Permeation tests with other dermal protective clothing materials and other clear coat formulations are needed to make recommendations about alternative materials.

Washington State workers' compensation data can be used to guide prevention efforts focused on occupational carbon monoxide (CO) poisoning. Between 2000 and 2005, a total of 345 individual claims comprising 221 different exposure incidents were identified for the 6-year time period. The construction industry had 43 (20%) CO incidents, followed by wholesale trade with 32 (15%), and agriculture with 27 (12%) incidents. Fuel-powered forklifts caused 29% of all incidents, while autos/trucks/buses were responsible for 26%. The number of forklift incidents in fruit packing and cold storage companies declined significantly from 1994 through 2007 (Spearman's rho = 0.6659, p0.01). While this study used multiple medical records from workers' compensation claims to identify CO poisoning, a surveillance system that lacks extensive medical records may rely principally on carboxyhemoglobin (COHb) tests. This study demonstrated that 71% of the identified workers' compensation claims had associated COHb tests. The recurrence and timing of CO poisoning as well as control of the CO-generating source were determined. Approximately 8% of all work sites had recurring CO poisoning incidents. Two percent experienced a recurrent incident within 16 days of the initial incident, and 6% experienced a recurrent incident between 16 days and 3 years after the initial incident. Sixty-seven percent of claimants exposed to CO were not in direct control of the CO-generating source; this has implications for CO prevention and underscores the need for all employees to be trained on CO hazards.

Urinary 1,6-hexamethylene diamine (HDA) may serve as a biomarker for systemic exposure to 1,6-hexamethylene diisocyanate (HDI) in occupationally exposed populations. However, the quantitative relationships between dermal and inhalation exposure to HDI and urine HDA levels have not been established. We measured acid-hydrolyzed urine HDA levels along with dermal and breathing-zone levels of HDI in 48 automotive spray painters. These measurements were conducted over the course of an entire workday for up to three separate workdays that were spaced approximately 1 month apart. One urine sample was collected before the start of work with HDI-containing paints and subsequent samples were collected during the workday. HDA levels varied throughout the day and ranged from nondetectable to 65.9 microg l(-1) with a geometric mean and geometric standard deviation of 0.10 microg l(-1) +/- 6.68. Dermal exposure and inhalation exposure levels, adjusted for the type of respirator worn, were both significant predictors of urine HDA levels in the linear mixed models. Creatinine was a significant covariate when used as an independent variable along with dermal and respirator-adjusted inhalation exposure. Consequently, exposure assessment models must account for the water content of a urine sample. These findings indicate that HDA exhibits a biphasic elimination pattern, with a half-life of 2.9 h for the fast elimination phase. Our results also indicate that urine HDA level is significantly associated with systemic HDI exposure through both the skin and the lungs. We conclude that urinary HDA may be used as a biomarker of exposure to HDI, but biological monitoring should be tailored to reliably capture the intermittent exposure pattern typical in this industry.

We conducted a quantitative dermal and inhalation exposure assessment of monomeric and polymeric 1,6-hexamethylene diisocyanates (HDI) in 47 automotive spray painters from North Carolina and Washington State. We report here the use of linear mixed modeling (LMM) to identify the primary determinants of dermal exposure. Dermal concentrations of HDI, uretidone, biuret, and isocyanurate were significantly higher in 15 painters who did not wear coveralls or gloves (N = 51 paint tasks) than in 32 painters who did wear coveralls and gloves (N = 192 paint tasks) during spray painting. Regardless of whether protective clothing was worn, isocyanurate was the predominant species measured in the skin [geometric mean (GM) = 33.8 ng mm(-3)], with a 95% detection rate. Other polyisocyanates (GMor = 0.17 ng mm(-3)) were detected in skin during23% of the paint tasks. According to marginal R(2) statistics, mixed models generated in this study described no36% of the variability in dermal concentrations of the different polyisocyanates measured in painters who did not wear protective clothing. These models also described 55% of the variability in dermal concentrations of isocyanurate measured in all painters (N = 288 paint tasks). The product of analyte-specific breathing-zone concentration (BZC) and paint time was the most significant variable in all the models. Through LMM, a better understanding of the exposure pathways governing individual polyisocyanate exposures may be achieved. In particular, we were able to establish a link between BZC and dermal concentration, which may be useful for exposure reconstruction and quantitatively characterizing the protective effect of coveralls and gloves. This information can be used to reduce dermal exposures and better protect automotive spray painters from potential adverse health effects.

We conducted a repeated exposure-assessment survey for task-based breathing-zone concentrations (BZCs) of monomeric and polymeric 1,6-hexamethylene diisocyanate (HDI) during spray painting on 47 automotive spray painters from North Carolina and Washington State. We report here the use of linear mixed modeling to identify the primary determinants of the measured BZCs. Both one-stage (N = 98 paint tasks) and two-stage (N = 198 paint tasks) filter sampling was used to measure concentrations of HDI, uretidone, biuret, and isocyanurate. The geometric mean (GM) level of isocyanurate (1410 microg m(-3)) was higher than all other analytes (i.e. GM < 7.85 microg m(-3)). The mixed models were unique to each analyte and included factors such as analyte-specific paint concentration, airflow in the paint booth, and sampler type. The effect of sampler type was corroborated by side-by-side one- and two-stage personal air sampling (N = 16 paint tasks). According to paired t-tests, significantly higher concentrations of HDI (P = 0.0363) and isocyanurate (P = 0.0035) were measured using one-stage samplers. Marginal R(2) statistics were calculated for each model; significant fixed effects were able to describe 25, 52, 54, and 20% of the variability in BZCs of HDI, uretidone, biuret, and isocyanurate, respectively. Mixed models developed in this study characterize the processes governing individual polyisocyanate BZCs. In addition, the mixed models identify ways to reduce polyisocyanate BZCs and, hence, protect painters from potential adverse health effects.

Production workers in the collision repair industry are potentially exposed to many harmful chemicals, including isocyanates. Of particular concern is the burden of work-related asthma in this industry that likely reflects exposures to the isocyanates in two-part paints. The main objectives of this study were to gather information about: (i) the collision repair industry business model, (ii) the number of collision repair production workers potentially exposed to isocyanates, (iii) additional chemical and physical exposures of concern, (iv) current health and safety practices in the industry, (v) the health and safety perceptions and needs of business owners and managers, and (vi) strategies to reduce exposure and increase employer and worker awareness. Data were gathered using a combination of key informant interviews, field investigations, and a statewide needs assessment survey. Although a response bias cannot be excluded, the 69% response rate suggests that the survey results are likely representative of Washington State's collision repair industry. Collision repair was determined to be a male-dominated industry chiefly comprising small, nonunionized, family-run businesses. Many shops face numerous safety and health challenges resulting from a combination of misinformation within the industry, insufficient funds to address workplace health and safety concerns, and social barriers to enforcing best practices within the shops. Most notably, inappropriate selection and use of respirators and gloves likely contribute significantly to isocyanate exposures. Collision repair workers are potentially exposed to a variety of additional chemical and physical hazards that deserve attention. This industry requires health and safety intervention of both an educational campaign and technical assistance. Any such intervention must account for the financial, demographic, and social characteristics of this industry.

Micromass cell culture systems for rat embryo midbrain (CNS) and limb bud (LB) cells were employed to assess the in vitro developmental toxicity of the human and veterinary anthelmintic albendazole (ABZ) and its sulfoxide metabolite (SOABZ). ABZ is reported to be teratogenic in rats, and is extensively metabolized to the sulfoxide derivative. It has been postulated that SOABZ is the reactive metabolite responsible for albendazole's developmental toxicity and anthelmintic activity in vivo. Three parameters for assessing developmental toxicity were measured: cell growth, differentiation, and cytotoxicity. CNS and LB cultures were equivalent in their sensitivities to both ABZ and SOABZ. ABZ was approximately 50-fold more potent than SOABZ. Immunohistochemical determinations of tubulin organization revealed that both ABZ and its sulfoxide metabolite elicit an accumulation of cells in the mitotic phase of the cell cycle. Since ABZ is one of the most potent agents tested in the micromass system to date, this anthelmintic should be considered a potential developmental toxicant.

Macular degeneration is the most widespread untreatable cause of visual impairment. Since it is age-related, it is expected to increase as the mean age of the population increases. Many individuals with this impairment wish to develop or retain reading ability, which is inhibited by the resulting central scotomas, or blind spots. The Pepper Visual Skills for Reading Test has been developed to evaluate the visual skills used in reading under these circumstances. Previously shown to be highly reliable, the Pepper VSRT is also shown to be highly valid when compared to a standardized oral reading evaluation. It can be adapted to a wide variety of clinical applications.

Radiator repair workers in Washington State have the greatest number of very elevated (> or =60 microg/dL) blood lead levels of any other worker population. The goals of this study were to determine the number of radiator repair workers potentially exposed to lead; estimate the extent of blood lead data underreporting to the Occupational Lead Exposure Registry; describe current safety and health practices in radiator repair shops; and determine appropriate intervention strategies to reduce exposure and increase employer and worker awareness. Lead exposure in Washington State's radiator repair workers was assessed by reviewing Registry data and conducting a statewide survey of radiator repair businesses. This study revealed that a total of 226 workers in Washington State (including owner-operators and all employees) conduct repair activities that could potentially result in excessive exposures to lead. Approximately 26% of radiator repair workers with elevated blood lead levels (> or =25 microg/dL) were determined to report to Washington State's Registry. This study also revealed a lack of awareness of lead's health effects, appropriate industrial hygiene controls, and the requirements of the Lead Standard. Survey respondents requested information on a variety of workplace health and safety issues and waste management; 80% requested a confidential, free-of-charge consultation. Combining data derived from an occupational health surveillance system and a statewide mail survey proved effective at characterizing lead exposures and directing public health intervention in Washington State.

Elevated blood lead levels (BLLs) in adults can damage the cardiovascular, central nervous, reproductive, hematologic, and renal systems. The majority of cases are workplace-related. U.S. Department of Health and Human Services recommends that BLLs among all adults be reduced to25 microg/dL. The highest BLL acceptable by standards of the U.S. Occupational Safety and Health Administration is 40 microg/dL. The mean BLL of adults in the United States is3 microg/dL.This report covers cases of adults (agedor = 16 years) with BLLsor = 25 microg/dL, as reported by 25 states during 1998-2001.Since 1987, CDC has sponsored the state-based Adult Blood Lead Epidemiology and Surveillance (ABLES) program to track cases of elevated BLLs and provide intervention consultation and other assistance. Overall ABLES program data were last published in 1999 for the years 1994-1997. This report provides an update with data from 25 states reporting foror = 2 years during 1998-2001. During that period, the ABLES program funded surveillance in 21 states - Alabama, Arizona, Connecticut, Iowa, Maryland, Massachusetts, Michigan, Minnesota, New Jersey, New York, North Carolina, Ohio, Oklahoma, Oregon, Pennsylvania, Rhode Island, South Carolina, Texas, Washington, Wisconsin, and Wyoming. Four additional states - California, Nebraska, New Hampshire, and Utah contributed data without CDC funding.During 1998-2001, the overall program's annual mean state prevalence rate for adults with BLLsor = 25 microg/dL was 13.4/100,000 employed adults. This compares with 15.2/100,000 for 1994-1997. Yearly rates were 13.8 (1998), 12.9 (1999), 14.3 (2000), and 12.5 (2001). For adults with BLLsor = 40 microg/dL, the overall program's annual mean state prevalence rare during 1998-2001 was 2.9/ 100,000 employed adults. This compares with 3.9/100,000 for 1994-1997. Yearly rates were 3.3 (1998), 2.5 (1999), 2.9 (2000), and 2.8 (2001).Although certain limitations exist, the overall ABLES data indicate a declining trend in elevated BLLs among employed adults.ABLES-funded states increased from 21 to 35 in 2002, and more detailed reporting requirements were put into effect. These, and other improvements, will enable the ABLES program to work more effectively toward its 2010 target of eliminating all cases of BLLsor = 25 microg/dL in adults caused by workplace exposures.

The key to the rehabilitation of a complex activity, such as sailing, involves the determination of specific goals or subtasks. For each specific goal, both visual and nonvisual mechanisms are considered. This report identifies the specific goals that should be met to enable an experienced skipper to maintain his or her ability to sail a yacht. Mechanisms are described that either failed or enabled achievement of the specific goals.

Most patients with low vision request help with reading. Despite improvements in the assessment of visual functions, determining the appropriate magnification for reading still often involves a trial and error approach. Recent research has shown that with accurate and systematic assessments of vision, the required magnification can be predicted but this magnification needs to be much higher than has been previously recommended. This paper presents a systematic approach to enable practitioners to determine the power of a near addition or simple magnifier needed to assist patients with mild or moderate low vision who may present seeking help for reading. Guidelines for appropriate referral to low vision services are also provided.

Monomeric and oligomeric 1,6-hexamethylene diisocyanate (HDI) and isophorone diisocyanate (IPDI) are components of catalyst hardeners in two-part polyurethane coating systems. Exposure to these isocyanates in the collision repair industry has been associated with increased risk for work-related asthma; however their quantitation remains a challenging task. Four analytical methods were compared: modified version of the National Institute for Occupational Safety and Health Method 5525 (NIOSH); liquid chromatography and mass spectrometry (LC/MS) using 1-(2-methoxyphenyl)piperazine (MPP) as the derivatizing reagent; modified version of the Occupational Health and Safety Administration Method 42/PV2034 (OSHA); and modified version of the Omega ISO-CHEK® Method (WA-DOSH). Five levels of a widely used clear coat hardener were spiked onto sampling media. A reference value was calculated by using a hardener NCO titration and manufacturer composition data. Intra- and inter-method variability was determined. All methods measuring NCO-HDI monomer, NCO-IPDI monomer, NCO-IPDI oligomers, and total NCO mass (except OSHA method) compared well against the reference values (slopes ≥ 0.816, R2 > 0.90). The NCO-HDI oligomer results for the NIOSH method compared well with the reference values (slope = 1.161, standard error = 0.046 and R2 = 0.98, p < 0.001) while WA-DOSH were above (slope = 2.293, standard error = 0.055 and R2 = 0.99, p < 0.001) and LC/MS were below (slope = 0.264, standard error = 0.011 and R2 = 0.98, p < 0.001) the reference values. The principal challenges associated with comparing methods were: 1) the reporting metrics were not always directly comparable and 2) not all methods reported all isocyanate species of interest. Although this present study provided valuable information, a more extensive investigation is required in order to critically evaluate these methodological differences.

Micromass cell culture systems for rat embryo midbrain (CNS) and limb bud (LB) cells were employed to assess the in vitro developmental toxicity of the benzimidazole analogs, mebendazole (MBZ), thiabendazole (TBZ), and nocodazole (NCZ), in addition to the classic microtubule inhibitor, colchicine. Comparison was made to albendazole (ABZ), a previously studied benzimidazole anthelmintic. Two parameters for assessing developmental toxicity were measured: differentiation and cytotoxicity. The relative potencies of the benzimidazole analogs in the micromass system (NCZ greater than MBZ approximately ABZ much greater than TBZ) mirrored their effectiveness in an assay for in vitro inhibition of mammalian tubulin polymerization. Colchicine also exhibits a high affinity for mammalian tubulin and was a potent inhibitor of cell proliferation, chondrogenesis, and neuronal differentiation. Immunofluorescent staining of Day 1 LB cultures with a monoclonal antibody to beta-tubulin revealed that these agents elicited mitotic arrest. Many anti-tubulin agents are teratogenic in rats and their in vivo developmental toxicity may reflect perturbation of microtubular structure or function. With the exception of TBZ, these agents should be considered potential developmental toxicants since they inhibit cell growth and differentiation of micromass cultures at nanomolar concentrations.

Prior research has suggested that two types of fast eye movements (FEMs) can be distinguished behaviorally. Foveating saccades respond to salient peripheral targets by directing the target image to the fovea. Non-foveating saccades include other FEMs such as nystagmus quick phase, saccades without visual stimuli and visually-directed saccades that direct target images to eccentric retina. Foveating saccades have a shorter initiation latency and are faster than non-foveating saccades. Following adaptation to central scotoma, patients tend to use preferred retinal loci for fixation (PRL). If PRL acquire the foveal characteristic of a retino-motor center then visually guided saccades would acquire the properties of foveating saccades. Using an objectively-calibrated 2-dimensional search coil, we measured saccades in response to salient, unpredictable targets. The saccades of normal observers were compared to the saccades of patients with long-standing macular scotomas. Although the saccades of patients consistently directed images to PRL, the saccades still had the latency and dynamic characteristics of non-foveating saccades. Moreover, the non-foveating saccades of patients were found to be less accurate than foveating saccades, showing a range effect (larger saccades undershoot with greater error than do smaller saccades). Apparently, patients with macular scotoma suppress rather than adapt a foveating saccade mechanism.

A review of the literature revealed that foveating saccades were found to be faster than other fast eye movements (FEMs) except optokinetic nystagmus (OKN) quick phase. In the present experiment, foveating saccades were compared to OKN quick phase in humans and were found to have higher maximum speeds and shorter durations. Unlike previous experiments, foveating saccades were made to targets at unpredictable distances, and active pursuit during OKN was discouraged. Previously reported differences between the speeds of foveating saccades and saccades to remembered target positions were replicated. Foveating saccades, therefore, can be distinguished from other FEMs on the basis of speed. This behavioral difference suggests that a distinctive mechanism exists for foveating targets.

Among the patients we tested, most of those who had lost normal macular function developed extrafoveal retinal loci which resulted in strongly preferred viewing angles for steady fixation. These patients used these extrafoveal retinal loci to scan lines of characters in patterns similar to patients with normal macular function. Although the scanning speed of these patients was adversely affected by their large size scotomas, their reading accuracy was not necessarily reduced. The assessment of scanning and reading performance in this population requires careful measurement of the visual skills involved in reading.

Statistical methods are considered for analysis of data arising from a mitotic chromosome loss assay in Saccharomyces cerevisiae strain D61.M. The methods make use of reproducibility trial data from the assay (presented herein) and previous data, which suggest a unimodal, ‘umbrella-patterned’ dose response. Computer simulations are employed to illustrate the operating characteristics of the umbrella response methods. These methods are generally applicable to any toxicity assay that exhibits a downturn in dose response. Experimental design considerations are also discussed. These include applications of 2-stage sampling rules to first gauge the dose window of peak response, then test if the response deviates significantly from untreated levels.

Low amplitude high frequency wavelets have been demonstrated to be ubiquitous in the visual system of animals and are observed in the ERG of man. Wavelets have also been observed super-imposed upon large slow waves obtained from electrodes on occipital scalp. Presently, the rather stereotypic wavelet repetition rate permitted the use of active analog filters tuned to 100 Hz, with a 60–200 Hz bandpass which produced no measurable distortion at 100 Hz. With this method we recorded a series of wavelets in 15 of 16 subjects that usually began from 35 to 40 msec following the onset of a 10 4 troland, 25° visual angle 100 msec flash. We then sought to determine the origin of these wavelets. Wavelets recorded between occiput (O z ) and vertex (C z ) had photopic spectral sensitivity that differed from that of ERG wavelets simultaneously recorded. Moreover, in a topographical study, wavelets recorded between C z and various lateral positions reached a maximum at O z ; and when adjacent bipolar electrode pairs were used, wavelet polarities inverted as pairs were moved across the occipital region. Thus wavelets recorded between 35 and 70 msec were likely generated from occipital cortex rather than retinal, subcortical, or diffuse cortical sites. In addition, the topographical distribution of slow wave (‘P100’) and wavelets differed. Wavelet latencies had a different relation to retinal illuminance than P100 latencies, suggesting that P100 and wavelets have different neurogeneses. Wavelets recorded between O z and C z thus reflect the earliest cortucal visual processing recorded in man.

In a recent presentation and following discussion among low vision practitioners, we were rather surprised to find a near consensus that central fields of someone with advanced maculopathy provided little useful information in prescribing visual aids and planning a rehabilitation program. Admittedly, by the time Age Related Maculopathies (ARM) or fundus flavimaculatus have advanced to the formation of an absolute central scotoma, central fields are of limited diagnostic use. However, other practitioners have argued that central fields are valuable in predicting functional capabilities [1,2]; arguments that have been supported in the laboratory by the recent work of LEGGE et al.[3], who identified the state of central fields as the best predictor of peak reading rate among their diverse sample of low vision individuals.

When a maculopathy advances to a stage where an absolute central scotoma forms, visual performance in tasks such as reading significantly deteriorates beyond a level predicted by loss in visual acuity1,2. Lore among low vision rehabilitation specialists identifies maculopathy as particularly troublesome to manage clinically. Even after compensation for the reduced visual acuity, other visual factors may hinder performance1,3 and need to be addressed. In addition, patients may have difficulty adapting oculomotor control to use functioning peripheral retina that has requisite function and field of view. Any one of these factors might limit visual performance of a given patient. In order to rehabilitate visual performance efficiently, assessment procedures need to be developed that will identify the performance-limiting factors.

Our investigations have yielded several characteristics of eye movement control in individuals with maculopathies which differ substantially from those found in normally sighted individuals. While ~70% of our subjects adopted one preferred viewing locus for fixation, 30% developed two or more eccentric loci. In addition, the variability of the eccentric fixation in these individuals increased with increasing scotoma size. For subjects with central scotomata ranging from 2° to 30° in diameter, 1–3° of uncertainty of retinal position would be common with standard visual field testing. In subjects with larger scotomata, shifts in fixation angle of >20° have been recorded. While mean drift velocity in these individuals (31 min of arc/s; range: 13-186 min of arc/s) was slightly larger than that recorded in normally sighted subjects with artificial scotomata (mean: 25 min of arc/s; range: 13-55 min of arc/s), more important was the relatively high drift velocities in particular individuals and/or drift direction which may position the scotoma in the path of the desired image. Our results reveal that accurate psychophysical testing, such as higher resolution visual fields or spatial contrast sensitivity testing of specific retinal loci, on individuals with maculopathies, necessitates image stabilization techniques.