Acrylamide: review of toxicity data and dose-response analyses for cancer and noncancer effects

Acrylamide (ACR) is used in the manufacture of polyacrylamides and has recently been shown to form when foods, typically containing certain nutrients, are cooked at normal cooking temperatures (e.g., frying, grilling or baking). The toxicity of ACR has been extensively investigated. The major findings of these studies indicate that ACR is neurotoxic in animals and humans, and it has been shown to be a reproductive toxicant in animal models and a rodent carcinogen. Several reviews of ACR toxicity have been conducted and ACR has been categorized as to its potential to be a human carcinogen in these reviews. Allowable levels based on the toxicity data concurrently available had been developed by the U.S. EPA. New data have been published since the U.S. EPA review in 1991. The purpose of this investigation was to review the toxicity data, identify any new relevant data, and select those data to be used in dose-response modeling. Proposed revised cancer and noncancer toxicity values were estimated using the newest U.S. EPA guidelines for cancer risk assessment and noncancer hazard assessment. Assessment of noncancer endpoints using benchmark models resulted in a reference dose (RfD) of 0.83 microg/kg/day based on reproductive effects, and 1.2 microg/kg/day based on neurotoxicity. Thyroid tumors in male and female rats were the only endpoint relevant to human health and were selected to estimate the point of departure (POD) using the multistage model. Because the mode of action of acrylamide in thyroid tumor formation is not known with certainty, both linear and nonlinear low-dose extrapolations were conducted under the assumption that glycidamide or ACR, respectively, were the active agent. Under the U.S. EPA guidelines (2005), when a chemical produces rodent tumors by a nonlinear or threshold mode of action, an RfD is calculated using the most relevant POD and application of uncertainty factors. The RfD was estimated to be 1.5 microg/kg/day based on the use of the area under the curve (AUC) for ACR hemoglobin adducts under the assumption that the parent, ACR, is the proximate carcinogen in rodents by a nonlinear mode of action. When the mode of action in assumed to be linear in the low-dose region, a risk-specific dose corresponding to a specified level of risk (e.g., 1 x 10-5) is estimated, and, in the case of ACR, was 9.5 x 10-2 microg ACR/kg/day based on the use of the AUC for glycidamide adduct data. However, it should be noted that although this review was intended to be comprehensive, it is not exhaustive, as new data are being published continuously.

Association of Healthcare Costs With Per Unit Body Mass Index Increase

OBJECTIVE

The objective of this study was to quantify the healthcare costs per unit increase in body mass index (BMI).

METHODS

This cross-sectional study included 35,932 employees and spouses in a manufacturing company who participated in an indemnity/PPO plan and one health risk appraisal during 2001 and 2002.

RESULTS

Within the BMI range of 25 to 45 kg/m, medical costs and pharmaceutical costs increased dollar 119.7 (4%) and dollar 82.6 (7%) per BMI unit, respectively, adjusted for age and gender. The adjusted medical costs related to diabetes and heart disease increased by dollar 6.2 and dollar 20.3 per BMI unit. The likelihood of having any medical claim increased 11.6% per BMI unit for diabetes and 5.2% for heart disease.

CONCLUSIONS

Each unit increase in BMI is associated with higher healthcare costs and increased likelihood of having claims for most major diagnostic codes and for diabetes and heart diseases.

Intrinsic and extrinsic effects in the temperature-dependent photoluminescence of semiconducting carbon nanotubes

The temperature dependence of the band gap of semiconducting carbon nanotubes was measured for ten different nanotube species. The unprecedented effectiveness in avoiding the effect of external strain, or any other effects originating from the surrounding environment, lead to an accurate measurement of the band gap temperature dependence, giving fundamental insight into the nanotube electron-phonon interaction. Small but reproducible energy shifts of the emission lines with temperature were observed, showing a moderate chirality dependence, well in agreement with recent theoretical calculations. In addition to the energy shift, a substantial narrowing of the emission lines was also observed. The removal of the temperature shift of the band gap allows the precise measurement of the effect of external strain on carbon nanotubes in different environments.

BMI, physical activity, and health care utilization/costs among Medicare retirees

OBJECTIVE

To examine the influence of physical activity (PA) and BMI on health care utilization and costs among Medicare retirees.

RESEARCH METHODS AND PROCEDURES

This cross-sectional study was based on 42,520 Medicare retirees in a U.S.-wide manufacturing corporation who participated in indemnity/preferred provider and one health risk appraisal during the years 2001 and 2002. Participants were assigned into one of the three weight groups: normal weight, overweight, and obese. PA behavior was classified into three levels: sedentary (0 time/wk), moderately active (1 to 3 times/wk), and very active (4+ times/wk).

RESULTS

Generalized linear models revealed that the moderately active retirees had US 1456 dollars, US 1731 dollars, and US 1177 dollars lower total health care charges than their sedentary counterparts in the normal-weight, overweight, and obese groups, respectively (p < 0.01). The very active retirees had US 1823 dollars, US 581 dollars, and US 1379 dollars lower costs than the moderately active retirees. Health care utilization and specific costs showed similar trends with PA levels for all BMI groups. The total health care charges were lower with higher PA level for all age groups (p < 0.01).

DISCUSSION

Regular PA has strong dose-response effects on both health care utilization and costs for overweight/obese as well as normal-weight people. Promoting active lifestyle in this Medicare population, especially overweight and obese groups, could potentially improve their well-being and save a substantial amount of health care expenditures. Because those Medicare retirees are hard to reach in general, more creative approaches should be launched to address their needs and interests as well as help reduce the usage of health care system.

FIA/MS analysis of temporally ozonated benzo[a]pyrene and pyrene and their reaction products: inhibition of gap junction-mediated intercellular communication

In this study, the polycyclic aromatic hydrocarbons, benzo[a]pyrene (BaP) and pyrene, were subjected to temporal ozonation. The products from ozonation of 5 mg l(-1) BaP and 5 mg l(-1) pyrene, for varying time intervals (0, 1, 2, 3, 4, 5, 6, 8, 10, 20, and 30 min) were tested for their effects on gap junction-mediated intercellular communication (GJIC) in Clone 9 rat liver cells. Additionally, the ozonation products were also analyzed by flow injection analysis/mass spectrometry (FIA/MS) and the results were compared with the toxicity observed in the GJIC assay. Treatment of the Clone 9 cells with 5 mg l(-1) of ozonated BaP products resulted in a decrease in GJIC that was inversely proportional to the length of ozonation. The products from 1 min of ozonation resulted in a 92% decrease in the rate of GJIC, but with >5 min ozonation, the products did not suppress GJIC. In contrast, pyrene (0.5 mg l(-1)) required >10 min of ozonation to alleviate its effects on GJIC. FIA/MS, using atmospheric pressure chemical ionization (APCI), demonstrated products with higher molecular weights (MW) than their corresponding parent compounds, BaP (MW 252) and pyrene (MW 202). Ozonation of pyrene formed significantly fewer products than BaP. More importantly, pyrene ozonation products were constant from 1 to 10 min, while BaP ozonation products seemed to vary between time intervals. With the longer ozonation times (20 and 30 min), BaP and pyrene formed similar products (m/z peaks 157, 111, and 96). The suppression of GJIC by ozonated products seemed to correlate with oxidation of the aromatic ring framework. Further oxidation (longer ozonation times) to lower MW products correlated with restoration of normal GJIC.

Potential immaturity of the T-cell and antigen-presenting cell interaction in cord blood with particular emphasis on the CD40-CD40 ligand costimulatory pathway

There are reports of immaturity of the neonatal immune system, which may explain the low incidence of graft-versus-host-disease (GVHD) after cord blood transplantation. The CD40 ligand (CD40L)-CD40 interaction is important in regulating the cellular immune response. We hypothesized that the neonatal immune system may show immaturity in this interaction. We studied the function of the CD40L-CD40 interaction in the T-cell interaction with B cells and monocytes in cord blood compared with adult blood in vitro. Consistent with previous reports, CD4+ T cells do not express CD40L after T-cell activation. In whole blood, adult monocytes, but not neonatal monocytes, were activated following T-cell activation. However, the activation of adult monocytes was not dependent on the CD40L-CD40 interaction. Using the CD40L trimer (Lt), we showed that cord B cells have comparable responses to CD40 ligation to those of the adult B cells. Both cord and adult monocytes do not respond as well as B cells and this is probably related to low density of expression of CD40. However, interferon-gamma up-regulated CD40 on adult monocytes but not on cord monocytes. This potentiated the adult monocyte response to CD40 ligation by CD40Lt. Our findings suggest that the neonatal CD40L-CD40 pair is immature in the cellular immune response involving monocytes and that interferon-gamma fails to activate neonatal monocytes for a response to CD40L. These findings suggest that in the inflammatory microenvironment of cord blood transplantation neonatal monocytes may play a minor role in the effector arm of the immune response. This finding may be one of several mechanisms for the low incidence of GVHD that is observed following cord blood transplantation. Also the ligand-receptor immaturity may contribute to the increased susceptibility of newborns to certain infections.

Jet injector compared with oral midazolam for preoperative sedation in children

BACKGROUND

This study compared onset of sedation and satisfaction with two needleless jet injectors with the oral route for the administration of midazolam.

METHODS

Forty-five children ages 1-6 years were randomly assigned to receive either 0.5 mg kg(-1) oral midazolam, 0.2 mg kg(-1) subcutaneous midazolam by J-Tip injector or 0.2 mg kg(-1) intramuscular midazolam by Bioject injector. After midazolam administration the children were monitored for oxygen saturation, heart rate and level of sedation (0, alert; 1, calm; 2, drowsy; 3, dozing; 4, asleep) every 2 min for 20 min by a physician blinded to the route of administration. Patient satisfaction, resistance to treatment, success of delivery, problems with separation, and acceptance of mask at the time of induction were evaluated after midazolam treatment.

RESULTS

The Bioject showed a faster onset of sedation than either the J-Tip injector or the oral midazolam (P < 0.05). The children were significantly less satisfied with the Bioject and J-Tip administration vs oral midazolam (P < 0.05). There were no differences in resistance, success of delivery, problems with separation, mask acceptance, arterial oxygen saturation or heart rate.

CONCLUSION

Despite children being less satisfied with Bioject injection of midazolam, the procedure is safe, effective and provides a more rapid onset of preoperative sedation in children than either the J-Tip injection or oral route.

Relationship of body mass index and physical activity to health care costs among employees

This study examined the relationship between physical activity and health care costs by different weight groups. The study sample consisted of 23,490 active employees grouped into normal weight, overweight, and obese categories. After adjustment for covariates, physically moderately active (1 to 2 times/week) and very active (3 + times/week) employees had approximately $250 less paid health care costs annually than sedentary employees (0 time/week) across all weight categories. The difference was approximately $450 in the obese subpopulation. The maximum possible savings was estimated to be 1.5% of the total health care costs if all obese sedentary employees would adapt a physically active lifestyle. As a strategy to control escalating health care costs, wellness programs should facilitate engagement in moderate physical activity of at least 1 to 2 times a week among sedentary obese people and help them to maintain this more active lifestyle.)

The relationship between National Heart, Lung, and Blood Institute Weight Guidelines and concurrent medical costs in a manufacturing population

PURPOSE

To explore the relationship between the 1998 National Heart, Lung, and Blood Institute (NHLBI) weight guidelines and concurrent medical costs.

DESIGN

Cross-sectional study.

SETTING

In a nationwide manufacturing corporation (General Motors Corporation).

SUBJECTS

A total of 177,971 employees, retirees, and their adult dependents who were enrolled in Indemnity/PPO health insurance plan during the years 1996 and 1997 and completed one health risk appraisal (HRA) in the same period.

MEASURES

The participants were categorized into six weight groups according to the NHLBI 1998 guidelines (body mass index [BMI] < 18.5, 18.5-24.9, 25-29.9, 30-34.9, 35-39.9, > or = 40 kg/m2). The height and weight data were collected by self-reported values on an HRA or biometric screening completed during 1996 to 1997. To represent the typical medical costs in a given group, the median, instead of mean, medical charges were used in this article. The annual median medical charges (including drug charges) for years 1996 and 1997 were compared among the six weight groups by using Wilcoxon rank sum tests. The differences in median charges were also tested between the normal weight group and the other five groups for each of the 10 gender-age subgroups (five age groups: 19-44, 45-54, 55-64, 65-74, 75+).

RESULTS

Overall median medical costs were consistent with the NHLBI weight guidelines. The normal-weight group costs the least and both underweight and overweight-obesity groups cost more. The median medical costs of the six weight groups were $3184, $2225, $2388, $2801, $3182, and $3753, respectively, with statistical differences existing between any two groups of the last five categories. The underweight groups, especially in females, were not consistent with the guidelines in the two young groups (ages 19-44 and 45-54). An inconsistent relationship between medical costs and BMI groups was seen in the oldest males (age 75+).

CONCLUSIONS

The six weight groups defined by the 1998 NHLBI guidelines are consistent with concurrent medical costs. Except for the underweight group (BMI < 18.5 kg/m2), medical costs gradually increased with BMI. Given that the prevalence of obesity continues to increase in western countries, effective weight control programs would help avoid a substantial amount of medical costs associated with overweight/obesity and related diseases.

Immune escape mechanisms of childhood ALL and a potential countering role for DC-like leukemia cells

BACKGROUND

Pre-B ALL cells generally elicit a weak immune host response, due to poor expression of co-stimulatory molecules and/or suppression of immune function. A possible way to enhance immunogenicity of pre-B ALL cells is to convert them to DC-like cells.

METHODS

To study the effect of ALL cells on T-cell function, ALL cells were incubated with T adult cells activated by OKT3 MAb. Liquid culture of de novo pre-B ALL cells for 7 days, in a medium containing IL-1alpha, IL-3, IL-7, Flt 3 ligand (L) and tumor-necrosis factor alpha (TNF-alpha) produced DC-like cells. These were evaluated for morphology, viability, phenotype, as measured by flow cytometry, and function, including MLR.

RESULTS

Pre-B ALL cell-lines NALM-6, BALM and de novo pre-B ALL cells failed to stimulate T cells, but suppressed stimulated T cells. The DC-like cells displayed characteristic features of DCs: filiform cytoplasmic projections, and phenotypic expression of co-stimulatory molecules CD80/86, MHC Class I and II molecules, CD83 and CD1a. Genetic monoclonality study confirmed their leukemic origin. In a 5-day MLR culture, the DC-like cells potently activated allogeneic adult and cord CD4+ and CD8+ T cells. Furthermore, both CD4+ and CD8+ T cells were primed towards a Type I. No such effect was seen with unmanipulated de novo pre-B ALL cells.

DISCUSSION

DC-like cells can be generated from childhood pre-B ALL cells and are potent stimulators of adult and naïve cord CD8+ T cells via CD4+ cells. These cells may form part of an immunotherapy strategy to overcome tolerance to ALL cells.

The association between synthetic bedding and adverse respiratory outcomes among skin-prick test positive and skin-prick test negative children

BACKGROUND

Synthetic bedding has been associated with increased child wheeze and also higher allergen levels in several studies. We aimed to examine whether the association between synthetic bedding and adverse respiratory outcomes was more evident among skin-prick test (SPT) positive children.

METHODS

A cross-sectional survey involving a population sample of 758 (81% of eligible) school children aged 8-10 years from randomly selected schools in the Australian Capital Territory in 1999. Parental questionnaires for ISAAC respiratory symptoms and child bedding were obtained. SPT results of 10 common allergens were available on 722 of the subjects (77% of those eligible). Synthetic pillow or quilt use was termed synthetic upper bedding.

RESULTS

Synthetic quilt use was associated with asthma (Adjusted Odds Ratio 1.67 (1.05, 2.65)), recent wheeze (AOR 1.63 (1.03, 2.59)) and allergic rhinoconjunctivitis (AOR 2.11 (1.33, 3.34)) among SPT-positive children. However, these associations were not apparent for SPT-negative children. Similarly, increasing synthetic upper bedding use was associated with more than 12 episodes of wheeze among SPT-positive children (AOR 1.69 (1.08, 2.64), P=0.02, per category) but not SPT-negative children (AOR 0.77 (0.26, 2.21), P=0.6, per category).

CONCLUSION

The apparent association between synthetic upper bedding and adverse respiratory outcomes was evident among SPT-positive but not SPT-negative children. Prospective intervention studies that aim to examine the effect of upper bedding composition on child asthma among SPT-positive children are required.

Which clinical subgroups within the spectrum of child asthma are attributable to atopy?

STUDY OBJECTIVES

The contribution of atopy to childhood asthma has been debated. We aimed to examine the relationship between atopy and asthma, taking into account differences in respiratory symptoms and disease severity.

DESIGN

A cross-sectional asthma survey involving the following: (1) a population sample of 758 (81% of eligible) school children aged 8 to 10 years from randomly selected schools in the Australian Capital Territory in 1999, and (2) a hospital-based sample of 78 (70% of eligible) children attending the hospital for asthma. Skin-prick test results to 10 common aeroallergens were available on 722 children and 77 children, respectively. Baseline spirometry was obtained on a subset of school children (n = 515, 78% of eligible).

RESULTS

The association between atopy and wheeze by wheeze frequency over the past year was as follows: no episodes (odds ratio [OR], 1.00 [reference]), 1 to 3 episodes (OR, 3.27; 95% confidence interval [CI], 2.15 to 4.97), 4 to 12 episodes (OR, 3.44; 95% CI, 1.75 to 6.75), and > 12 episodes (OR, 8.70; 95% CI, 3.07 to 24.55), with a higher population attributable fraction (PAF) for > 12 episodes (75%) than 1 to 3 episodes (49%). Atopy was moderately related to asthma ever (OR, 2.09; 95% CI, 1.52 to 2.85; PAF, 33%) but strongly related to 1999 hospital attendance for asthma (OR, 16.95; 95% CI, 6.76 to 42.48; PAF, 89%). Adjustment for child age, gas heater use, and maternal smoking near the child did not materially alter these findings.

CONCLUSIONS

The clinical features of frequent wheeze or hospital asthma attendance are largely attributable to atopy, but infrequent wheeze or a history of asthma ever are not. Atopic children are overrepresented in the severe range of the asthma spectrum.

Self-reported utilization of preventive health services by retired employees age 65 and older

OBJECTIVES

Increased utilization of preventive services among the aging has been associated with improved health status and decreased medical costs. We sought to examine the use of the Health Risk Appraisal (HRA) in benchmarking compliance and characterizing those retired employees who met preventive service guidelines.

DESIGN

A retrospective cohort study of retired employees age 65 and older.

SETTING

Nation-wide health promotion program offered by General Motors Corporation.

PARTICIPANTS

59,670 retired General Motors employees age 65 and older who participated in a nationwide mailed HRA health promotion program.

MEASUREMENTS

Preventive health services compliance was measured using selected HRA questions. Gender, HRA participation patterns, overall health risk status, medical plan selection and disease status were examined as predictors of increased compliance. Multivariate logistic regression models were developed to test the relative contributions of participant characteristics to increased utilization.

RESULTS

The self-reported HRA data indicated that compliance levels were higher than national averages. The Healthy People 2000 goals for the preventive services studied were met and exceeded (with the exception of tetanus immunization). Higher compliance was associated with being male, younger than 70 years, multiple-year HRA participation, overall low risk status and HMO insurance plan selection.

CONCLUSION

The results from the HRA indicated that this population participated at a higher level than a comparable national sample exceeding goals set by Healthy People 2000.

Changes in health risks among the participants in the United Auto Workers--General Motors LifeSteps Health Promotion Program

PURPOSE

To examine health risk changes among participants of a multicomponent worksite health promotion program.

DESIGN

A study using health risk changes among health risk appraisal (HRA) participants linked to program participation records. Baseline risk and participation in multiple programs were examined in relation to risk change in multivariate models.

SETTING

Worksite health promotion programming sponsored by the United Auto Workers (UAW) and General Motors (GM).

SUBJECTS

Active employees (12,984) who voluntarily participated in an HRA in each of two program years.

INTERVENTION

The nationwide program was a mailed HRA and a 1-800 nurse line. A pilot program (implemented in two cities) added screening, wellness programs, a materials resource, and, for high risk participants, health coaching and vouchers for medical office visits.

MEASURES

Using 13 selected health risk factors from the HRA, changes in overall health risks were measured as program outcomes in three ways: one-directional, net, and risk status change.

RESULTS

A greater decrease in the number of health risks was observed with increased program participation. The decrease was significantly related to the number of baseline risk factors and eligibility for high risk programs. Associated with program participation, the number of people at low risk status increased from 70.1% to 71.3% at year 2 among nationwide participants and from 52.4% to 58.9% among pilot participants.

CONCLUSIONS

Participation was associated with a significant impact on health risk. Baseline risk of participants and eligibility for high risk programs were necessary factors to control when measuring program effects on health risk changes.

The relationship between low level nitrogen dioxide exposure and child lung function after cold air challenge

BACKGROUND

Nitrogen dioxide (NO(2)) or home gas appliance use has been inconsistently associated with adverse respiratory outcomes in childhood.

OBJECTIVES

(i) To examine the contribution of home gas appliance type and personal NO(2) exposure. (ii) To examine the relationship between NO(2) exposure and child lung function and respiratory history. (iii) To assess whether these relationships vary by house dust mite sensitization status.

METHODS

A cross-sectional survey of 344 children (71% of the eligible group) with a mean age of 9.1 years from four randomly selected schools in the Australian Capital Territory from July to September 1999. Study measurements included a parental questionnaire, NO(2) exposure by passive gas samplers, skin prick testing for 10 aeroallergens and lung function at rest and after cold air challenge.

RESULTS

Total NO(2) exposure was low with a mean concentration of 10.1 ppb. No associations were found between NO(2) exposure or gas appliance use and asthma, wheeze or baseline lung function. Personal NO(2) exposure was associated with a reduction in forced expiratory volume in one second (FEV1)/forced vital capacity (FVC) after cold air challenge (adjusted difference - 0.12% (- 0.23% to - 0.01%) per 1 ppb increase). After exclusion of children who had home heating changed because of asthma, gas heater use was also significantly associated with a reduction in this measure (adjusted difference - 2.0% (- 3.7% to - 0.2%)). There was some evidence that these reductions were greater among the non-mite-sensitized children.

CONCLUSIONS

The effect of low-level NO(2) exposure on these respiratory outcomes was not marked. The possible effect of low-level NO(2) exposure on non-specific bronchial reactivity requires confirmation. Future studies on NO(2) and respiratory health should include measures of house dust mite sensitization and bronchial hyper-responsiveness.

Internal associations among health-risk factors and risk prevalence

OBJECTIVE

To explore risk associations between health variables and to compare these associations with the prevalence of each risk.

METHODS

Manufacturing-company employees (N=16,879) completed a self-reported health risk appraisal with on-site biometric screening.

RESULTS

Risk prevalence and risk association findings differed by gender, age, and overall risk level. Risks that were most highly associated with other risks were different from risks that were most prevalent.

CONCLUSIONS

The findings suggest that in addition to risk prevalence, individual characteristics and the level of association between risks are also important to consider when planning health interventions.

Plasma naltrexone during opioid detoxification

Orogastric naltrexone is used for opioid detoxification, but it is not known how gastric absorption affects plasma concentrations of the drug. We measured plasma naltrexone during orogastric naltrexone, given in repeated doses of 12.5 mg, 25 mg, 50 mg and 50 mg. Plasma naltrexone was measured after each naltrexone dose. The increase in plasma naltrexone was highly variable between patients during orogastric administration. Adequate detoxification was questioned in 4 of 10 patients because plasma naltrexone did not increase above 5 ng/ml. There was a negative correlation between plasma naltrexone and the presence of withdrawal symptoms on the day after the procedure (r = -0.78, P < 0.05). These results show that the increase in plasma naltrexone is variable during orogastric administration and this may impair successful detoxification.

System requirements for a computerised patient record information system at a busy primary health care clinic

A prototyping approach was used to determine the essential system requirements of a computerised patient record information system for a typical township primary health care clinic. A pilot clinic was identified and the existing manual system and business processes in this clinic was studied intensively before the first prototype was implemented. Interviews with users, incidental observations and analysis of actual data entered were used as primary techniques to refine the prototype system iteratively until a system with an acceptable data set and adequate functionalities were in place. Several non-functional and user-related requirements were also discovered during the prototyping period.

Predicting the learning and consultation time in a computerized primary healthcare clinic

Managers would like to know how long it takes healthcare service providers to achieve the same throughput of patients per day that they were used to with a pen-and-paper system. This study has been undertaken to derive a model for predicting the time it takes a service provider from a previously disadvantaged community to enter a patient's record in terms of his or her experience and the number of data units that have to be captured. A model was also derived to predict the average consultation time in terms of the number of data units that are captured by an experienced service provider. It can be inferred that healthcare service providers should be allowed at least 6 months of computerized system experience before any decisions about the success of the technology introduction can be made.