Comparative Potency Method for Cancer Risk Assessment: Application to Diesel Particulate Emissions1

An estimation of the human lung cancer “unit risk” from diesel engine particulate emissions has been made using a comparative potency approach. This approach involves evaluating the tumorigenic and mutagenic potencies of the particulates from four diesel and one gasoline engine in relation to other combustion and pyrolysis products (coke oven, roofing tar, and cigarette smoke) that cause lung cancer in humans. The unit cancer risk is predicated on the linear nonthreshold extrapolation model and is the individual lifetime excess lung cancer risk from continuous exposure to 1 μg carcinogen per m³ inhaled air. The human lung cancer unit risks obtained from the epidemiologic data for coke oven workers, roofing tar applicators, and cigarette smokers were, respectively, 9.3 × 10^?4, 3.6 × 10^?4, and 2.2 × 10^?6 per μg particulate organics per m³ air. The comparative potencies of these three materials and the diesel and gasoline engine exhaust particulates (as organic extracts) were evaluated by in vivo tumorigenicity bioassays involving skin initiation and skin carcinogenicity in SENCAR mice and by the in vitro bioassays that proved suitable for this analysis: Ames Salmonella microsome bioassay, L5178Y mouse lymphoma cell mutagenesis bioassay, and sister chromatid exchange bioassay in Chinese hamster ovary cells. The relative potencies of the coke oven, roofing tar, and cigarette smoke emissions, as determined by the mouse skin initiation assay, were within a factor of 2 of those determined using the epidemiologic data. The relative potencies, from the in vitro bioassays as compared to the human data, were similar for coke oven and roofing tar, but for the cigarette smoke condensate the in vitro tests predicted a higher relative potency. The mouse skin initiation bioassay was used to determine the unit lung cancer risk for the most potent of the diesel emissions. Based on comparisons with coke oven, roofing tar, and cigarette smoke, the unit cancer risk averaged 4.4 × 10^?4. The unit lung cancer risks for the other, less potent motor-vehicle emissions were determined from their comparative potencies relative to the most potent diesel using three in vitro bioassays. There was a high correlation between the in vitro and in vivo bioassays in their responses to the engine exhaust particulate extracts. The unit lung cancer risk per μg particulates per m³ for the automotive diesel and gasoline exhaust particulates ranged from 0.20 × 10^?4 to 0.60 × 10^?4; that for the heavy-duty diesel engine was 0.02 × 10^?4. These unit risks provide the basis for a future assessment of human lung cancer risks when combined with human population exposure to automotive emissions.     

Effective targeted and community HIV/STD prevention programs

Community interventions and interventions targeting specific groups at risk of STDs/HIV have demonstrated significant impacts on sexual behavior, particularly condom use and safer sex. The scientific evidence suggests the factors that make these interventions particularly effective include the establishment of community, including business and CBO partnerships; maintainance of the intervention post-research funding; and buy-in by the community or target group. The modification of risky normative beliefs through the use of opinion leaders and role models, and through intervention delivery by peer educators, is an important facet of such interventions. Interventions delivered by health professionals, absent a community base, appear to be unsuccessful. Where cultures or subcultures are targeted, the close involvement of such groups in the design and delivery of messages is critical to their success. Diffusion of interventions through existing social networks further extends the intervention into the community and acts to reinforce and maintain changes in peer norms toward safer sexual behavior. The available data confirm that community or medical infrastructure-based interventions are effective in changing sexual behavior and can reach a wider range of the population than face-to-face programs if they incorporate peer educators as role models in modifying norms, and if diffusion of the intervention is integral to the design.     

"Languaging" factors affecting clients' acceptance of forgiveness intervention in marital therapy

Forgiveness is a significant intervention for healing interpersonal injury. Yet therapists do not often use forgiveness intervention. Employing a semantic perspective and a survey design (n = 307), this study investigated whether the language used to rationalize forgiveness intervention (set at five levels: personal growth, relationship reconciliation, spiritual issue, others' growth, and pardoning/condoning) may affect its acceptability. Gender, problem type, and choice were also included in the analyses. Overall, forgiveness was found to be an acceptable intervention. A pardoning/condoning rationale led to significantly lower acceptability ratings. Other results are discussed. We conclude that therapists should be less apprehensive about using forgiveness, but need to inform themselves better concerning its purpose, process, and articulation.     

Perspectives on workplace disability management: a review of the literature

Work-related musculoskeletal injuries represent a major source of work disability. While many employers recognize the importance of workplace disability management approaches and are assuming greater responsibility for preventing and minimizing work-related disability, questions about the effectiveness of these interventions exist. The purposes of this article are to: 1) describe the essential components of workplace disability management programs related to musculoskeletal injuries; 2) review the literature on disability management practices based on research evidence by focussing on workplace-based interventions and the role of the workplace; and 3) provide recommendations for disability management in the prevention and reduction of disability, and the rehabilitation of injured workers with musculoskeletal work injuries. The literature suggests that employer participation, a supportive work climate and cooperation between labour and management are crucial factors in facilitating return to work. Given the complexity of the disability management process and the numbers of individuals involved, it is essential that all workplace parties work together to achieve the goal of safe and early return to work.     

Perspectives on work (re)entry for persons with disabilities: implications for clinicians

Despite the prevalence of government funding to support employment opportunities for persons with disabilities, real jobs for this population still appear to be elusive. McMaster University researchers examined how six stakeholder groups defined workplace (re)entry success for persons with disabilities. Focus groups and individual interviews were conducted with representation from employers, unions, persons with disabilities, co-workers, supervisors and human resource departments. Participants numbered 86 and the average age was 42. Participant comments provided the researchers with rich data related to the study objectives. Success was perceived as not only a match between the employee and the job but also a win-win for employer and employer, a uniquely defined set of circumstances based on the specific individual and their environment as well as respect for the individual's dignity and quality of life. This article discusses the study and its outcomes and highlights implications for clinicians.     

Why mentoring in the workplace works

Workplaces are ideal contexts for mentoring relationships between adults and older youth. To teach the competencies required in contemporary workplaces (many of which are equally useful in other settings), mentors need to use sophisticated teaching behaviors, which the authors characterize as reflective questioning and problem solving.     

The impact of touch-tone data entry on reports of HIV and STD risk behaviors in telephone interviews

Respondents concerns about privacy can decrease reporting of HIV and STD risk behaviors in general population telephone surveys. The purpose of this paper is to describe the results of an experimental study evaluating whether one method for increasing privacy, touch-tone data entry (TTDE), is effective in increasing estimates of sexual behaviors from a population-based survey. We conducted a random-digit-dial telephone survey of adults in New Jersey (n = 405), with half the respondents using TTDE for answering sexual behavior questions. TTDE led to increased reports of same-sex sexual behavior, certain HIV and STD risk factors, and concern about one s risk for HIV and STD transmission. TTDE also narrowed the difference between men s and women s reports of the number of different sexual partners over the past 10 years. The feasibility and limitations of TTDE are discussed, as well as possible alternative interpretations that consider the impact of TTDE on the dynamics of the interaction between the respondent and the interviewer.     

Predictors of substance abuse treatment outcomes in Tennessee

In planning and implementing programs to treat substance abuse, it is important to understand which factors influence post-treatment abstinence.This article identifies and analyzes several variables important in predicting the likelihood of abstinence among substance abuse clients. The data used in this study was collected from 1,350 clients treated for alcohol or drug abuse in residential, halfway house, or outpatient facilities in Tennessee. We analyzed 22 variables as possible treatment outcome predictors by using two statistical procedures: stepwise logistic regression analysis and Quick, Unbiased, Efficient, Statistical Tree (QUEST) analysis, a tree-structured classification algorithm analysis. We found one pretreatment, five in-treatment, and three post-treatment variables to be significant predictors of treatment outcome: previous treatment history, perceived helpfulness of the treatment, simultaneous treatment for mental health, number of days in treatment,completion of treatment, special skills training during treatment, obtaining healthcare services for major physical health problem after treatment, living with someone using alcohol or drugs post treatment, and arrest record since treatment.     

Multi-family psychoeducation groups in the treatment of children with mood disorders

This study examined the impact of adjunctive multi-family psychoeducation groups (MFPG) on mood-disordered children aged 8 to 11 and their families. Participants were 35 children and 47 parents from families randomly assigned to either immediate MFPG plus treatment as usual (n = 18) or a 6-month wait-list condition plus treatment as usual (n = 17). At the 6 month follow up, immediate treatment families reported: Increased parental knowledge about childhood mood symptoms; increased positive family interactions as reported by the parent; increased perceptions of parental support as reported by children; and increased utilization of appropriate services by families. Expected impact on decreasing negative family interactions was not found. Results are largely consistent with hypothesized findings and support the need to further investigate the adjunctive role of psychoeducation in the treatment of childhood mood disorders.