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The article discusses a system of dollar income classification developed by the American Marketing Association's subcommittee on dollar classification of incomes. The author notes that the subcommittee wishes to break income categories into twelve different classes. Also noted is a plan of income tabulation for the United States Census Bureau, specifically in the tabulation of family income. According to the author, standard of living values will be based on the amount of money charged to families for the use of rental units.

Researchers and policy makers increasingly recognize the need to adapt to future changes in climate, given that past emissions of greenhouse gases have already committed the world to some level of climate change. However, the current understanding of the costs and benefits of adaptation measures is still fairly rudimentary, and far from comprehensive. An assessment is presented of the current state of knowledge on the magnitude of adaptation costs in the United States. While incomplete, the studies suggest that adaptation cost could be as high as tens or hundreds of billions of dollars per year by the middle of this century. Key studies are identified in each sector, and the cost estimates and approaches to cost estimation are surveyed. Methodological issues are highlighted in interpreting, comparing, and aggregating adaptation cost estimates. Policy recommendations are made along with appropriate steps to make future adaptation cost studies more comparable within and across sectors and more accessible and relevant to policy and decision makers. Policy relevance Designing and implementing climate change adaptation policy requires good information about the effectiveness and cost of available adaptive options. The current state of knowledge on adaptation costs in the United States is assessed and significant gaps in the literature are highlighted – particularly in terms of sectoral and geographic coverage – as well as inconsistencies in methodologies and assumptions that hamper comparison across studies. Critical steps are identified that can be taken to make adaptation cost studies more accessible and useful to decision makers. The findings and recommendations are relevant to adaptation cost studies globally, not just in the United States. [ABSTRACT FROM AUTHOR]

Riverine dams alter both the physical environment and water chemistry, thus affecting species assemblages within these environments. In the United States, dam construction is on the decline and there is a growing trend for dam removal. The Choctawhatchee, Pea, and Yellow Rivers Watershed Management Authority had initiated the permitting process for placing a reservoir dam on the Little Choctawhatchee River (LCR), a tributary to the Choctawhatchee River. The purpose of the proposed reservoir was water supply, and while the permit application has been suspended, history shows that this or related projects are likely to arise in the future. This study collected data on nutrient quality seasonally (four times) from 12 sites in the LCR watershed from October 2007 to June 2008 in order to determine pre-dam conditions and to compare these data to historical and regional information. Historical and current nutrient concentrations were elevated throughout the watershed, in most cases above suggested criteria, and indicated that water quality of the river was and continues to be nutrient rich. A future reservoir at recent levels of water quality will likely be highly eutrophic, and anthropogenic influences will further stress this ecosystem and its water quality as the urban region expands. [ABSTRACT FROM AUTHOR]

Background: Intra-arterial administration of melphalan chemotherapy has shown promise in the treatment of retinoblastoma. This report describes our results using superselective intra-arterial melphalan in patients with newly diagnosed retinoblastoma and those who were treated for progression after systemic chemotherapy. Methods: This is a retrospective review of all retinoblastoma patients treated with intra-arterial melphalan at the University of California, San Francisco from March 2010 to August 2012. Twenty eyes (16 patients) underwent 40 intra-arterial melphalan infusions, and dose was determined by age. Patients were treated at monthly intervals and received a range of 1-5 treatments. Response to therapy, toxicity, and procedural radiation exposure was assessed. Results: All patients are alive without metastatic disease at a median follow-up of 14.5 (1-29) months. Treatment with enucleation or external beam radiation was avoided in 11/20 eyes (55%) overall [6/12 (50%) in newly diagnosed eyes and 5/8 (63%) in refractory/relapsed eyes]. Response rates (per the International Classification of Retinoblastoma) were as follows: 6/7 (86%) in groups A-C and 5/13 (38%) in groups D and E. Nonhematologic and hematologic toxicities were minimal and comparable with those in previous reports. The mean procedural radiation dose was 20.2 ± 11.9 mGy per eye per procedure. Conclusion: Superselective intra-arterial melphalan therapy is effective for less advanced eyes but further modifications to therapy are required to improve results in eyes with advanced retinoblastoma. [ABSTRACT FROM AUTHOR]

Abstract: The literature concerning the relationship between polychlorinated biphenyl (PCB) exposure and Intelligence (IQ) is not entirely consistent. Two studies showed inverse associations between PCBs and IQ in cohorts of children whose mothers consumed Great Lakes fish contaminated with PCBs and other organochlorines (Jacobson & Jacobson 1996; Stewart et al. 2008). Another study from the general US population, where women were exposed to background levels of PCBs, showed no association between PCBs and IQ (Gray et al. 2005). The current report examines two potential sources of inconsistency across studies: 1) confounding with non-PCB organochlorines [Hexachlorobenzene (HCB), dichlorodiphenyldichloroethylene (DDE), and Mirex]; and 2) the presence of negative confounding (i.e., suppressor variables). The former could confound PCBs and lead to spurious associations (Type I errors), while the latter could suppress PCB associations and obscure true associations (Type II errors). These issues were explored through the analysis of associations between placental levels of organochlorines and IQ in children at 9 and 11years of age in the Oswego study. Neither DDE nor mirex was related to lower IQ at either age; PCBs predicted lower IQ at both ages; and hexachlorobenzene (HCB) appeared as a significant predictor of IQ at the 11-year assessment. However, analysis of the IQ data set as a whole showed that both PCBs and HCB predicted lower IQ in a generally independent fashion. There was, however, overlap in the variance in some cases, and the pattern of findings between the two was remarkably similar. These results may provide some evidence for the potential involvement of non-PCB organochlorines in the Oswego study. To explore negative confounding, we analyzed the relationships between PCB exposure and demographic variables as well as the unadjusted and adjusted relationships between PCB and IQ. Results revealed that placental PCB levels were associated with older mothers who were more educated and came from higher socioeconomic strata. Due to this fact, unadjusted relationships between PCBs and IQ appeared null or slightly positive. After control for confounders, several significant negative associations between PCBs and IQ were revealed. These data might suggest that inadequate control for confounders in PCB studies, where negative confounding is present, may bias results toward the null (Type II error) rather than spurious associations (Type I error). This pattern of confounding with PCB exposure in the Oswego study also has implications for the assessment of risk. The most highly exposed children came from families with somewhat higher socioeconomic status, and tended to score in the average to above-average range, well above IQ scores that are considered “at risk.” Further, such children were exposed prenatally to PCBs through maternal consumption of PCB-contaminated Great Lakes fish in the early 1990s, when PCB levels were higher than today. [Copyright &y& Elsevier]

Alabama has at least 83 species of native crayfish reported, more than any other state in the United States. Information associated with crayfish distribution, life history, and ecological importance in Alabama is extremely limited. The objective of this research is to determine the presence and relative abundance of crayfish species in the southeastern coastal plain of Alabama. Crayfish were collected at 50 sites within the Choctawhatchee River, Pea River, Yellow River, and Patsaliga Creek watersheds by electrofishing and hand excavation. Twelve crayfish taxa were collected, with 10 successfully identified to species. Procambarus suttkusi (Choctawhatchee Crayfish) was found at 40 sites and was the most widespread and abundant of the aquatic species. Procambarus versutus (Sly Crayfish) and Cambarus graysoni (Twospot Crayfish) were also found to be common aquatic species. Cambarus (Tubericambarus) sp. B was the most abundant primary burrower, and C. (Lacunicambarus) sp. B was a common burrower. Species with less than 10 individuals collected were considered rare and were as follows: Procambarus acutus (White River Crawfish), P. okaloosae (Okaloosa Crayfish), C. latimanus (Variable Crayfish), C. ludovicianus (Painted Devil Crayfish), and C. striatus (Ambiguous Crayfish). [ABSTRACT FROM AUTHOR]

Abstract: Background: The Cavidi viral load assay and the ultra-sensitive p24 antigen assay (Up24 Ag) have been suggested as more feasible alternatives to PCR-based HIV viral load assays for use in monitoring patients infected with HIV-1 in resource-limited settings. Objectives: To describe the performance of the Cavidi ExaVir Load™ assay (version 2.0) and two versions of the Up24 antigen assay and to characterize their agreement with the Roche Monitor HIV-1 RNA assay (version 1.5). Study design: Observational study using a convenience sample of 342 plasma specimens from 108 patients enrolled in two ACTG clinical trials to evaluate the performance characteristics of the Up24 Ag assay using two different lysis buffers and the Cavidi ExaVir Load™ assay. Results: In analysis of agreement with the Roche assay, the Cavidi assay demonstrated superiority to the Up24 Ag assays in accuracy and precision, as well as sensitivity, specificity, and positive and negative predictive values for HIV-1 RNA ≥400, ≥1000 and ≥5000copies/mL. Logistic performance curves indicated that the Cavidi assay was superior to the Up24 assays for viral loads greater than 650copies/mL. Conclusions: The results suggest that the Cavidi ExaVir Load assay could be used for monitoring HIV-1 viral load in resource-limited settings. [ABSTRACT FROM AUTHOR]

The main purpose of this study was to evaluate the ability of a human exposure-response model, which describes ozone-induced changes in forced expiratory volume in 1 second (FEV1) across a wide range of dynamic exposure conditions, to predict responses in independent data. We first conducted an n-fold cross-validation of the model using samples of the original EPA data from which the model was developed. We then identified seven more recently published studies with controlled exposures to a wide range of ozone exposure patterns relevant to the current ambient ozone health standard and used the model to calculate the mean predicted responses for the exposure conditions of the individual studies that we compared to the mean observed responses reported in these studies. The n-fold cross-validation indicated good internal agreement between mean predicted and mean observed responses in the original data used to develop the model. The model accurately captured the patterns of response in each of the seven independent studies with a tendency to overpredict the observed responses by about 1 percentage point of FEV1 decrement on average. We conclude that the model is currently capable of predicting human FEV1 responses across a wide range of dynamic exposure conditions and anticipate further improvements in predictions with the addition of low-concentration exposure data. [ABSTRACT FROM AUTHOR]

We analyze historical data to conduct an exploratory structural investigation into the process that Harriet Tubman used to free her family and friends as a member of the New York State Underground Railroad (UGRR).We suggest that she accomplished this feat because of her ability to rely on embedded (Granovetter 1985; Uzzi 1996) network contacts that allowed her to bridge structural holes (Burt 1992) and link with people with whom she was not previously linked (Lin et al., 2001). We conclude by discussing the importance of network analysis for providing empirical meaning to historical events and episodes. [ABSTRACT FROM AUTHOR]

Objectives. We identified factors associated with testing HIV positive in a prison system performing voluntary HIV testing on inmates and estimated the number of undetected HIV cases to evaluate the efficacy of risk-factor-based HIV testing. Methods. We used logistic regression to estimate associations between HIV serostatus and HIV risk behaviors, mental health, coinfection status, and sociodemographic characteristics for prisoners entering the North Carolina Department of Correction from January 2004 through May 2006. We estimated the number of undetected HIV cases on the basis of age-, gender-, and race-specific HIV prevalences among prisoners and in the state. Results. Nearly 3.4% (718/21419) of tested prisoners were HIV positive. The strongest risk factors for infection among men were having sex with men (odds ratio [OR] = 8.0), Black race (OR = 6.2), other non-White race (OR = 7.4), and being aged 35 to 44 years (OR=4.1). The strongest risk factor among women was Black race (OR=3.8). Among HIV-positive prisoners, 65% were coinfected with HCV. We estimated that between 24% (223) and 61% (1101) of HIV cases remained undetected. Conclusions. The associations between HIV serostatus and a variety of factors highlight the potential limitations of risk-factor-based HIV testing in prisons, as do the high number of potential undetected HIV cases. [ABSTRACT FROM AUTHOR]

BACKGROUND: Several epidemiologic studies have demonstrated relationships between prenatal exposure to polychlorinated biphenyls (PCBs) and modest cognitive impairments in infancy and early childhood. However, few studies have followed cohorts of exposed children long enough to examine the possible impact of prenatal PCB exposure on psychometric intelligence in later childhood. Of the few studies that have done so, one in the Great Lakes region of the United States reported impaired IQ in children prenatally exposed to PCBs, whereas another found no association. OBJECTIVES: This study was designed to determine whether environmental exposure to PCBs predicts lower IQ in school-age children in the Great Lakes region of the northeastern United States. METHODS: We measured prenatal exposure to PCBs and IQ at 9 years of age in 156 subjects from Oswego, New York. We also measured > 50 potential predictors of intelligence in children, including repeated measures of the home environment [Home Observation for Measurement of the Environment (HOME)], socioeconomic status (SES), parental IQ, alcohol/cigarette use, neonatal risk factors, and nutrition. RESULTS: For each 1-ng/g (wet weight) increase in PCBs in placental tissue, Full Scale IQ dropped by three points (p = 0.02), and Verbal IQ dropped by four points (p = 0.003). The median PCB level was 1.50 ng/g, with a lower quartile of 1.00 ng/g and an upper quartile of 2.06 ng/g. Moreover, this association was significant after controlling for many potential confounders, including prenatal exposure to methylmercury, dichlorodiphenyldichloroethylene, hexachlorobenzene, and lead. CONCLUSIONS: These results, in combination with similar results obtained from a similar study in the Great Lakes conducted 10 years earlier, indicate that prenatal PCB exposure in the Great Lakes region is associated with lower IQ in children. [ABSTRACT FROM AUTHOR]

This study evaluated biological integrity expectations of fish assemblages in wadeable streams for the Alabama portion of the Choctawhatchee River watershed using a multimetric approach. Thirty-four randomly selected stream sites were sampled in late spring 2001 to calibrate an index of biotic integrity (IBI). Validation data were collected during the spring 2001, and summer and fall of 2003 from disturbed and least- impacted targeted sites (n = 20). Thirty-five candidate metrics were evaluated for their responsiveness to environmental degradation. Twelve metrics were selected to evaluate wadeable streams and four replacement metrics were selected for headwater streams. Scores that ranged from 58 to 60 were considered to be representative of excellent biotic integrity (none found in this study), scores of 48-52 as good integrity (31% of the sites in this study), 40-44 as fair (43%), 28-34 as poor (21%), and 12-22 as very poor (5%). Of the four stream condition categories (urban, cattle, row crop, and least impacted), the IBI scores for urban and cattle sites differed significantly from least-impacted sites. Row crop sites, although not significantly different from least-impacted, tended to have greater variability than the other categories. Lower IBI scores at both urban and cattle sites suggest that the IBI accurately reflects stream impairment in the Choctawhatchee River drainage. [ABSTRACT FROM AUTHOR]

This study qualitatively surveyed freshwater mussel assemblages at 24 sites in the Choctawhatchee, Yellow, and Conecuh-Escambia river drainages of southeastern Alabama and northwest Florida in 2004. A specific focus of the study was to determine the current status of seven narrowly endemic candidate species: Margaritifera marrianae, Fusconaia escambia, Hamiota australis, Pleurobema strodeanum, Ptychobranchus jonesi, Quincuncina burkei, and Villosa choctawensis. Presence-absence analysis was used to compare 2004 data to recent historical records from the 1990s. There was no significant difference between the number of taxa found in the 1990s and in 2004. There was, however, a significant decrease from the 1990s to 2004 in the number of candidate species found at a site and the number of sites at which candidate species were found. [ABSTRACT FROM AUTHOR]

Analyzes data from a study on watersheds in an undergraded U.S. ecoregion to identify key environmental factors that explained stream fish assemblage patterns and to evaluate the relative influence of environmental factors operating at different spatial scale. Factors that influenced streams and their fish assemblages; Description of the study area; Details of watershed conditions; Data analysis; Results.

Riverine and palustrine wetland plant communities were examined in order to propose a multimetric plant index of biotic integrity. The objectives were to determine the structural and functional attributes of these wetland plant communities, calibrate reference conditions in assessing aquatic plant communities, provide methods for further development and testing of the index, and present a case study. The index is based on a rapid assessment method using the information collected from a species list and cover estimates. Sampling was done using a modified relevé sampling approach with a modified Braun-Blanquet Cover Abundance Scale Method for estimating percent cover. More than 20 characteristics of aquatic plant communities were evaluated and 12 metrics in five categories were developed. Structural metrics focused on community composition, key indicator species such as number of Carex and Potamogeton species, and guild type. Functional metrics included sensitivity and tolerance measures; percent emergent, pioneer, and obligate wetland species; and the number of weed species as a substitute metric. Abundance was estimated based on evenness of average cover densities. Individual condition was suggested as a measure of the lowest extremes of biotic integrity. Palustrine study sites ranged across a disturbance gradient from 'least-impacted' to 'poor'; riverine study sites ranged from high quality to some of the most degraded riverine sites in the Great Lakes region. Ninety-five species of aquatic vascular plants were found in 42 families. The most common families were Cyperaceae (15 species), Polygonaceae (9 species), and Juncaceae (6 species). Fourteen submergent, four floating, two woody and 75 emergent aquatic plant taxa were found. Five species were on the endangered, threatened, or rare list for the State of Indiana. Sites receiving the highest index scores included several of the a priori least-impacted sites while the lowest scores were located near-field to a large industrial landfill. The index will need to be further validated and tested but shows potential as a rapid index of biotic integrity using aquatic plant assemblages. [ABSTRACT FROM AUTHOR]

Examines childbearing patterns among women victims of child sexual abuse in North Carolina. Age at birth of first child; Parity; Comparison with nonabused mothers; Number of children.

Focuses on Piano Duet, the one-piano/four hands competition category launched by the Music Teachers National Association (MTNA) of the U.S. for the senior level. Aims of the MTNA Board of Directors in launching the competition; History of the piano duet; Examples of composers who have created arrangements for piano duets.

This article focuses on the goals of the Music Teachers National Association (MTNA) in the U.S. The dominant vision of the MTNA always will be to continue enhancing its mission to advance the value of music study and music making to society and to support the professionalism of music teachers. Its vision also would be to reduce the number of adults who say, I used to play to take piano lessons, I used to play the piano, I used to play the clarinet. If people could just mobilize all the adults who once studied music, the concert halls would be full, music studios would have long waiting lists and the association's income would match training, experience and contributions to society. MTNA support of this professional goal could take several tracks. Music teachers could share the ideas of successful sight-reading programs, standards and competitions. They can also organize collaborative festivals, duet and ensemble competitions, expand chamber music competition, create music reading lending libraries and encourage music fund-raising read-a-thons. But most importantly, they could make sight reading a primary objective of weekly music lessons. The gap between performance repertoire and sight-reading skill is alarmingly wide for many, if not most of the students.

The article presents an editorial looking at aging and anti-aging treatments. According to the article, association studies have linked age-related changes in levels of the adrenal sex steroid dehydroepiandrosterone (DHEA) to signs of aging, including cognitive impairment and increased fat mass. The article refers to the study "DHEA in elderly women and DHEA or testosterone in elderly men," by K. S. Nair, et al., published in this issue of "New England Journal of Medicine." The article states that due to a loophole in U.S. legislation, DHEA is considered a dietary supplement rather than as a drug. The article discusses the U.S. Food and Drug Administration and why DHEA should be considered a drug.

This article focuses on changes made to the Senior Piano Competition of the Music Teachers National Association, as of December 2005. One of the most significant changes approved by Board of Directors was to move the senior concerto requirement to the division and national levels, with the state competition as only the solo literature component. Reasons for this change were to inspire more student involvement and simplify the logistics. This past fall, the State Executive Board of the North Carolina Music Teachers Association submitted a proposal to the State Presidents Advisory Council requesting reinstatement of the Senior concerto requirement.

Presents information on the Music Teachers National Association convention scheduled at the Omni Shoreham Hotel on March 24 to 28, 2001 in Washington, D.C. Featured convention artists; Master classes offered; Highlights of the convention.

Background: Symptom burden, medical comorbidities, and functional well-being of patients with chronic hepatitis C virus (HCV) initiating direct acting antiviral (DAA) therapy in real-world clinical settings are not known. We characterized these patient-reported outcomes (PROs) among HCV-infected patients and explored associations with sociodemographic, liver disease, and psychiatric/substance abuse variables., Methods and Findings: PROP UP is a large US multicenter observational study that enrolled 1,600 patients with chronic HCV in 2016-2017. Data collected prior to initiating DAA therapy assessed the following PROs: number of medical comorbidities; neuropsychiatric, somatic, gastrointestinal symptoms (PROMIS surveys); overall symptom burden (Memorial Symptom Assessment Scale); and functional well-being (HCV-PRO). Candidate predictors included liver disease markers and patient-reported sociodemographic, psychiatric, and alcohol/drug use features. Predictive models were explored using a random selection of 700 participants; models were then validated with data from the remaining 900 participants. The cohort was 55% male, 39% non-white, 48% had cirrhosis (12% with advanced cirrhosis); 52% were disabled or unemployed; 63% were on public health insurance or uninsured; and over 40% had markers of psychiatric illness. The median number of medical comorbidities was 4 (range: 0-15), with sleep disorders, chronic pain, diabetes, joint pain and muscle aches being present in 20-50%. Fatigue, sleep disturbance, pain and neuropsychiatric symptoms were present in over 60% and gastrointestinal symptoms in 40-50%. In multivariable validation models, the strongest and most frequent predictors of worse PROs were disability, unemployment, and use of psychiatric medications, while liver markers generally were not., Conclusions: This large multi-center cohort study provides a comprehensive and contemporary assessment of the symptom burden and comorbid medical conditions in patients with HCV treated in real world settings. Pain, fatigue, and sleep disturbance were common and often severe. Sociodemographic and psychiatric markers were the most robust predictors of PROs. Future research that includes a rapidly changing population of HCV-infected individuals needs to evaluate how DAA therapy affects PROs and elucidate which symptoms resolve with viral eradication., Trial Registration: (Clinicaltrial.gov: NCT02601820)., Competing Interests: Donna M. Evon has received research funding from Gilead. Michael Fried has received research funding from and served as a consultant for AbbVie, BMS, Gilead, and Merck, and TARGET PharmaSolutions. Stock in TARGET PharmaSolutions is held in an independently managed trust. Anna S. Lok has received research support from AbbVie, BMS, Gilead, and Merck; and served as an advisor for Gilead. Richard K. Sterling has received research support from AbbVie, BMS, Gilead, Merck, and Roche and served as a consultant for Merck, Bayer, Salix, AbbVie, Gilead, Jansen, ViiV, Baxter, and Pfizer. Joseph K. Lim has received research support (paid to Yale University) and served as a consultant for Bristol-Myers Squibb and Gilead. Nancy Reau has received research funding (paid to Rush) from AbbVie and Intercept and has served as a consultant for AbbVie, Gilead, Merck, and BMS. Souvik Sarkar served on a Gilead and Abbvie Advisory Board. David R. Nelson has received research grant support from AbbVie, BMS, Gilead, Janssen, and Merck. K. Rajender Reddy is an Ad-Hoc Advisor to Gilead, BMS, Janssen, Merck, and Abbvie and has received research support from Gilead, BMS, Janssen, Merck, and AbbVie (paid to the University of Pennsylvania). Adrian M. Di Bisceglie has received research support from AbbVie, BMS and Gilead and has served on advisory boards for AbbVie, BMS and Merck. Paul Stewart has served as a consultant to TARGET PharmaSolutions. Jipcy Amador served as a biostatistics intern at TARGET PharmaSolutions in 2017. Carol E. Golin and Bryce Reeve declare that they have no conflict of interests to disclose. This does not alter our adherence to PLOS ONE policies on sharing data and materials.

Context: Evidence-based clinical guidelines in endocrinology attempt to improve and standardize patient care. There has been an expansion in guideline production although some of the heterogeneous methods used to assess the quality of the underlying evidence base might limit interpretation and implementation., Design: Current and archived guidelines from major endocrine organizations were accessed. The organizations used six different methods to rate underlying evidence, including Grading of Recommendations Assessment, Development and Evaluation (GRADE). To allow direct comparison between guidelines produced by different organizations, the levels of evidence used to generate them were graded according to the standardized system: 'high' based on randomized, controlled trials and meta-analyses, 'moderate' based on nonrandomized studies and 'low' based on expert opinion., Results: There was an increase in guideline production over time (1995-2000 = 9, 2001-2005 = 12, 2006-2011 = 36). Three guidelines were updated with an average delay of 4·3 years and an increase in recommendations per guideline (21·1%). Encouragingly, whilst updates had similar levels of 'high'-quality evidence, there was increased reliance on 'moderate'-category evidence and less on 'low''-quality evidence' ('high', 6·3% vs 6·5%; 'moderate', 46·1% vs 59·1%; 'low', 47·7% vs 34·4%). A high proportion of 'low'-category evidence was seen throughout all organizations. Rarer conditions and recommendations concerning treatment efficacy were particularly reliant on 'low'-category evidence., Conclusions: The level of evidence underpinning current guidelines highlights areas in need of well-designed, collaborative clinical research. Furthermore, criteria to define when guideline updates are necessary are currently lacking. A standardized method of assessment, such as GRADE, would promote understanding and compliance by guideline users with the ultimate aim of enhancing patient care., (© 2012 Blackwell Publishing Ltd.)

Context: A human exposure-response (E-R) model previously demonstrated to accurately predict population mean FEV₁ response to ozone exposure has been proposed as the foundation for future risk assessments for ambient ozone., Objective: Fit the original and related models to a larger data set with a wider range of exposure conditions and assess agreement between observed and population mean predicted values., Materials and Methods: Existing individual E-R data for 23 human controlled ozone exposure studies with a wide range of concentrations, activity levels, and exposure patterns have been obtained. The data were fit to the original model and to a version of the model that contains a threshold below which no response occurs using a statistical program for fitting nonlinear mixed models., Results: Mean predicted FEV₁ responses and the predicted proportions of individuals experiencing FEV₁ responses greater than 10, 15, and 20% were found to be in agreement with observed responses across a wide range of exposure conditions for both models. The threshold model, however, provided a better fit to the data than the original, particularly at the lowest levels of exposure., Conclusion: The models identified in this manuscript predict population FEV₁ response characteristics for 18-35-year-old individuals exposed to ozone over a wide range of conditions and represent a substantial improvement over earlier E-R models. Because of its better fit to the data, particularly at low levels of exposure, the threshold model is likely to provide more accurate estimates of risk in future risk assessments of ozone-induced FEV₁ effects.

Polychlorinated biphenyls (PCBs) are persistent pollutants that are ubiquitous in the food chain, and detectable amounts are in the blood of almost every person in most populations that have been examined. Extensive evidence from animal studies shows that PCBs are neurotoxins, even at low doses. Interpretation of human data regarding low-level, early-life PCB exposure and subsequent neurodevelopment is problematic because levels of exposure were not similarly quantified across studies. We expressed the exposure levels from 10 studies of PCB and neurodevelopment in a uniform manner using a combination of data from original investigators, laboratory reanalyses, calculations based on published data, and expert opinion. The mainstay of our comparison was the median level of PCB 153 in maternal pregnancy serum. The median concentration of PCB 153 in the 10 studies ranged from 30 to 450 ng/g serum lipid, and the median of the 10 medians was 110 ng/g. We found that (a)) the distribution of PCB 153 exposure in most studies overlapped substantially, (b)) exposure levels in the Faroe Islands study were about 3-4-fold higher than in most other studies, and (c)) the exposure levels in the two recent U.S. studies were about one-third of those in the four earlier U.S. studies or recent Dutch, German, and northern Québec studies. Our results will facilitate a direct comparison of the findings on PCBs and neurodevelopment when they are published for all 10 studies.