Risk for pulmonary late effects in childhood Hodgkin lymphoma survivors

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Background: Survivors of Hodgkin lymphoma (HL) are at risk for pulmonary late effects, including pulmonary fibrosis (PF). Established risk factors such as younger age at diagnosis and specific therapeutic exposures explain a fraction of the risk for these outcomes. Notably, systemic inflammation and impaired telomere maintenance are associated with adverse pulmonary outcomes in adult populations, but have not been explored in cancer survivors. Our aim was to identify pulmonary diffusion defects in HL survivors, and evaluate the impact of short lymphocyte telomere length (LTL) and systemic inflammation on these outcomes. Methods: Blood samples, demographic and treatment data, and lung carbon monoxide diffusion capacity corrected for hemoglobin and alveolar volume (DLCO) were obtained from HL survivors ≥6 months off therapy and without history of relapse or transplant. LTL was measured by telomere flow FISH (Repeat Diagnostics), and age-based percentiles determined from population controls. Plasma elevations in pro-inflammatory cytokines (HCYTMAG panel, EMD Millipore) were detected on a Luminex platform. Associations between clinical features and most recent DLCO were determined by linear regression, adjusted for age, sex, radiation, and race/ethnicity. In a subset of subjects, cytokine levels and LTL were compared in survivors with DLCO above or below the mean using a Student t-test or Fisher’s Exact test, respectively. Results: Seventy-two HL survivors met inclusion criteria (mean age at diagnosis=14 years, range: 3-18 years). Mean off-therapy DLCO was 75% (range: 52-98%), below the lower limit of normal (76%) in healthy populations. DLCO was inversely associated with female sex (p = 0.002). Five of 24 survivors (21%) had LTL ≤10th percentile for age, but there was no difference in LTL relative to DLCO. Survivors with DLCO ≤75% had higher IL1α and IL1β levels (n = 30, p = 0.07). Conclusions: HL survivors had lower than expected DLCO, with females at highest risk for impaired pulmonary diffusion. Twice as many survivors as expected had LTL ≤10th percentile, and PF-related cytokine profiles were observed in survivors with lower DLCO, suggesting inflammation and telomere maintenance defects may contribute to late effects in HL survivors.

Exploratory analysis of ERCC2 DNA methylation in survival among pediatric medulloblastoma patients

AIM

Medulloblastoma is the most frequent malignant pediatric brain tumor. While survival rates have improved due to multimodal treatment including cisplatin-based chemotherapy, there are few prognostic factors for adverse treatment outcomes. Notably, genes involved in the nucleotide excision repair pathway, including ERCC2, have been implicated in cisplatin sensitivity in other cancers. Therefore, this study evaluated the role of ERCC2 DNA methylation profiles on pediatric medulloblastoma survival.

METHODS

The study population included 71 medulloblastoma patients (age <18years at diagnosis) and recruited from Texas Children's Cancer Center between 2004 and 2009. DNA methylation profiles were generated from peripheral blood samples using the Illumina Infinium Human Methylation 450 Beadchip. Sixteen ERCC2-associated CpG sites were evaluated in this analysis. Multivariable regression models were used to determine the adjusted association between DNA methylation and survival. Cox regression and Kaplan-Meier curves were used to compare 5-year overall survival between hyper- and hypo-methylation at each CpG site.

RESULTS

In total, 12.7% (n=9) of the patient population died within five years of diagnosis. In our population, methylation of the cg02257300 probe (Hazard Ratio=9.33; 95% Confidence Interval: 1.17-74.64) was associated with death (log-rank p=0.01). This association remained suggestive after correcting for multiple comparisons (FDR p<0.2). No other ERCC2-associated CpG site was associated with survival in this population of pediatric medulloblastoma patients.

CONCLUSION

These findings provide the first evidence that DNA methylation within the promoter region of the ERCC2 gene may be associated with survival in pediatric medulloblastoma. If confirmed in future studies, this information may lead to improved risk stratification or promote the development of novel, targeted therapeutics.

Second malignancy risk among pediatric, adolescent, and young adult survivors of fusion-positive and fusion-negative sarcomas: Results from the SEER database, 1992 through 2012

BACKGROUND

The current study builds on the hypothesis that cancer-predisposing germline mutations are less common among patients with fusion-positive (F+) sarcomas compared to those with fusion-negative (F-) sarcomas, resulting in a lower risk of developing second malignant neoplasms (SMNs) in those with F + sarcomas.

METHODS

Standardized incidence ratios (SIRs) for developing SMNs were evaluated in 4822 survivors of F + and 3963 survivors of F- sarcomas that were diagnosed between 1992 and 2012 in pediatric, adolescent, and young adult patients (aged birth-39 years) and reported in the Surveillance, Epidemiology, and End Results (SEER) database. Cox proportional hazards models (adjusted hazard ratio [aHR]) and competing risk methods (subhazard ratio [sHR]) were used to evaluate SMN risk in those with F- versus F + sarcomas while controlling for demographic and clinical variables.

RESULTS

SMN risk was found to be nearly 2-fold greater among survivors of F + sarcomas (SIR, 1.86; 95% confidence interval [95% CI], 1.48-2.30) and nearly 3-fold greater among survivors of F- sarcomas (SIR, 2.89; 95% CI, 2.30-3.59) compared with the reference population. Although SMN types were noted to be similar between the fusion groups, the rate of any SMN was noted to be greater among survivors of F- sarcomas (aHR, 1.38 [95% CI, 1.01-1.89] and sHR, 1.27 [95% CI, 0.94-1.73]) when compared with survivors of F + sarcomas. The difference was most notable for solid tumor SMNs after index sarcomas were diagnosed between 2002 and 2012, for which rates of SMN were >2-fold greater among survivors of F- sarcomas (aHR, 2.31 [95% CI, 1.20-4.48] and sHR, 2.24 [95% CI, 1.13-4.43]).

CONCLUSIONS

The findings of the current study highlight the increased SMN risk experienced by survivors of sarcoma and demonstrate higher SMN rates in survivors of F- sarcomas compared to those with a history of F + sarcomas. Cancer 2016;122:3492-3500. © 2016 American Cancer Society.

Weight loss advice and prospective weight change among overweight firefighters

BACKGROUND

Obesity compromises firefighter safety, yet more than 70% of firefighters are overweight. Though healthcare professionals are encouraged to counsel overweight patients, the effectiveness of weight counseling is not consistent across studies.

OBJECTIVE

Examine longitudinal changes in cardiovascular risk factors and determine the role of healthcare professional weight loss advice on six-month weight changes among a national sample of male, overweight and obese firefighters.

METHODS

This study included baseline and six-month assessments of 757 firefighters. Medical and demographic data were collected using questionnaires. Investigators collected height, weight, percent body fat, waist circumference, blood pressure, and fasting serum samples (total cholesterol, high-density lipoprotein, low-density lipoprotein, glucose). Multilevel linear regression assessed the association between weight advice and outcomes.

RESULTS

Participants lost an average of 0.55 kg (95%CI: 0.17-0.93), and experienced significant improvements in systolic blood pressure (mean: 3.75 mm Hg; 95% CI: 2.35-5.14) and non-significant improvements in other clinical outcomes. Healthcare professional weight advice was not significantly associated with weight loss or other outcomes.

CONCLUSION

Similar to other studies, results show little benefit of low intensity weight loss counseling. Additional research is needed to identify effective and feasible weight management strategies to address firefighter obesity.

Abstract 5215: Parental and birth characteristics and childhood lymphoma in Texas, 1995-2011

Purpose: In the United States, lymphoma represents approximately one-third of all malignancies in those less than 20 years of age. As most cases are of unknown etiology, the identification of risk factors for the prevention of childhood lymphoma is critical. Parental and birth characteristics are often evaluated in studies of childhood cancer to determine the role of inborn variation on disease risk. Thus we sought to evaluate the role of parental and birth characteristics on the risk of childhood lymphoma.

Material and Methods: Cases (n = 374) were obtained from the Texas Cancer Registry (TCR) and limited to children born in Texas during or after 1995 and diagnosed with a lymphoma between 1995-2011. Diagnostic information came from the TCR, and case birth characteristic data was obtained from linked Texas birth certificates provided by the Center for Health Statistics. A randomly selected group of 10 controls for each case with subsequent birth characteristic data available was obtained from linked birth certificates. Multinomial logistic regression was used to generate relative-risk ratios (aRRR) and 95% confidence intervals (CI), adjusted for relevant covariates, to evaluate the association between several parental and birth characteristics and lymphoma risk (overall and by subtype).

Results: Most parental and birth characteristics were not associated with risk of childhood lymphoma. However, two factors were associated with lymphoma risk overall and by subtype: maternal race/ethnicity and infant sex. When compared to non-Hispanic white mothers, Hispanic mothers were more likely to have offspring that developed: 1) any lymphoma (aRRR: 1.09; 95% CI: 0.85-1.40) and 2) non-Hodgkin excluding Burkitt lymphoma (aRRR: 1.42; 95% CI: 0.96-2.11). The reverse was seen for non-Hispanic black mothers. There was also a disparity in risk by infant sex. Specifically, female children were at a decreased risk of developing all lymphomas (aRRR: 0.59; 95% CI: 0.47-0.74); Hodgkin lymphoma (aRRR: 0.65; 95% CI: 0.46-0.92); and Burkitt lymphoma (aRRR: 0.18; 95% CI: 0.10-0.33) when compared to male children. Additionally, paternal nativity was suggested to increase overall lymphoma risk (aRRR: 1.29; 95% CI: 0.96-1.73); an increase specifically suggested among those diagnosed with Hodgkin lymphoma (aRRR: 1.46; 95% CI: 0.93-2.32).

Conclusion: In this relatively large population-based study of these factors on the risk of childhood lymphoma, we found little evidence that parental and birth characteristics were strongly associated with disease risk.

Citation Format: Erin C. Peckham, Michael E. Scheurer, Heather E. Danysh, Austin L. Brown, Joseph Lubega, Philip J. Lupo. Parental and birth characteristics and childhood lymphoma in Texas, 1995-2011. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 5215.

Weight Advice Associated With Male Firefighter Weight Perception and Behavior

INTRODUCTION

The high prevalence of overweight and obesity threatens the health and safety of the fire service. Healthcare professionals may play an important role in helping firefighters achieve a healthy weight by providing weight loss counseling to at-risk firefighters. This study characterizes the impact of healthcare professional weight loss advice on firefighter weight perceptions and weight loss behaviors among overweight and obese male firefighters.

METHODS

A national sample of 763 overweight and obese male firefighters who recalled visiting a healthcare provider in the past 12 months reported information regarding healthcare visits, weight perceptions, current weight loss behaviors, and other covariates in 2011-2012. Analyzed in 2013, four unique multilevel logistic regression models estimated the association between healthcare professional weight loss advice and the outcomes of firefighter-reported weight perceptions, intentions to lose weight, reduced caloric intake, and increased physical activity.

RESULTS

Healthcare professional weight loss advice was significantly associated with self-perception as overweight (OR=4.78, 95% CI=2.16, 10.57) and attempted weight loss (OR=2.06, 95% CI=1.25, 3.38), but not significantly associated with reduced caloric intake (OR=1.26, 95% CI=0.82, 1.95) and increased physical activity (OR=1.51, 95% CI=0.89, 2.61), after adjusting for confounders.

CONCLUSIONS

Healthcare professional weight loss advice appears to increase the accuracy of firefighter weight perceptions, promote weight loss attempts, and may encourage dieting and physical activity behaviors among overweight firefighters. Healthcare providers should acknowledge their ability to influence the health behaviors of overweight and obese patients and make efforts to increase the quality and frequency of weight loss recommendations for all firefighters.

SOD2 genetic variant associated with treatment-related ototoxicity in cisplatin-treated pediatric medulloblastoma

Manganese superoxide dismutase (MnSOD), encoded by the SOD2 gene, is involved in the detoxification of superoxide anion. Superoxide is likely a source of oxidative stress in the cochlea following treatment with platinum agents and radiation. Therefore, we examined SOD2 variants in association with ototoxicity among cisplatin-treated childhood medulloblastoma patients. Blood samples were obtained from 71 eligible patients treated for pediatric medulloblastoma at Texas Children’s Cancer Center (1987–2010). Ototoxicity was defined as requiring the use of a hearing aid sometime after the initiation of therapy. DNA was genotyped on the Illumina HumanOmni-1 Quad BeadChip. A linkage disequilibrium (LD)-based single-nucleotide polymorphism (SNP) selection strategy was used to identify a minimal set of informative variants. Associations between SNPs and ototoxicity were assessed using logistic regression. Of the 71 eligible patients, 26 (37%) suffered from cisplatin-related ototoxicity. Study participants were primarily male (73%) and non-Hispanic white (42%). Five SOD2 variants (rs7855, rs5746151, rs5746136, rs2758331, and rs4880) identified by the LD-based selection strategy were genotyped. After correcting for multiple comparisons, the C-allele of the rs4880 variant was significantly associated with ototoxicity (odds ratio = 3.06, 95% confidence interval: 1.30–7.20) in adjusted models. The rs4880 T > C substitution results in a Val > Ala amino acid change at position 16 of the MnSOD mitochondrial targeting sequence. The Ala variant, which has been associated with increased MnSOD activity, was associated with hearing damage in this study. Platinum-based therapies increase the expression of MnSOD, which may result in an abundance of hydrogen peroxide, a reactive oxygen species. Therefore, oxidative stress may be an important mechanism in therapy-related cochlear damage.

Abstract 5576: MnSOD polymorphism is associated with ototoxicity in pediatric medulloblastoma patients

Purpose: The SOD2 gene encodes manganese superoxide dismutase (MnSOD) and is critical for superoxide anion detoxification. Variants in SOD2 have been associated with noise-induced hearing loss, and animal models suggest MnSOD expression is up-regulated in the cochlea after treatment with platinum-based chemotherapeutic agents. Therefore, we examined the role of SOD2 variants on ototoxicity among cisplatin-treated childhood medulloblastoma patients.

Methods: Peripheral blood samples were obtained from 100 patients treated for pediatric medulloblastoma or supratentorial primitive neuroectodermal tumor at Texas Children's Cancer Center or MD Anderson Cancer Center between 1982 and 2009. Demographic, clinical, and treatment information was abstracted from patient medical records. A diagnosis of ototoxicity was assigned to patients whose medical records indicated they had received cisplatin chemotherapy and required the use of a hearing aid ≥1 year following the completion of primary therapy. DNA was genotyped on the Illumina HumanOmni-1 Quad BeadChip (San Diego, CA). A linkage disequilibrium-based single nucleotide polymorphism (SNP) selection strategy was used to identify a minimal set of informative common variants (minor allele frequency ≥5%). The association between each SNP and ototoxicity was assessed using multivariable logistic regression, assuming a log-additive model. Adjusted models included confounders (age at diagnosis, gender, craniospinal radiotherapy dose, cisplatin dose, amifostine therapy, and ethnicity) selected using a change in estimate approach.

Results: Study participants were primarily male (73.2%) and non-Hispanic white (42.3%) with a mean age at diagnosis of 7.3 years. Of the 71 eligible patients with available information, 26 (36.6%) suffered from cisplatin-related ototoxicity. Five SOD2 variants (rs7855, rs5746151, rs5746136, rs2758331, rs4880) identified by the LD-based selection strategy were available in the genotyped data. After correcting for multiple comparisons, the C allele of the rs4880 variant was significantly associated with ototoxicity (OR = 3.00; 95% CI: 1.32-6.82) in adjusted models.

Conclusions: In this study, the SOD2 rs4880 variant was associated with ototoxicity. The rs4880 T&gt;C substitution results in a Val&gt;Ala amino acid change at position 16 of the MnSOD mitochondrial targeting sequence. Specifically, the Ala-variant, which has been associated with increased MnSOD activity, was associated with hearing damage in this study. Platinum-based therapies increase the expression of MnSOD, which may result in an abundance of hydrogen peroxide, a reactive oxygen species. Therefore oxidative stress may be an important mechanism in therapy-related cochlear damage. Characterizing genetic predictors of ototoxicity susceptibility may aid in prevention strategies and potentially identify novel antioxidant therapeutic targets.

Citation Format: Austin L. Brown, Philip J. Lupo, Mehmet F. Okcu, Ching C. Lau, Surya P. Rednam, Michael E. Scheurer. MnSOD polymorphism is associated with ototoxicity in pediatric medulloblastoma patients. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 5576. doi:10.1158/1538-7445.AM2015-5576

Abstract 853: The role of germline microRNA-related polymorphisms on pediatric medulloblastoma prognosis and survival

Background: Five-year survival for pediatric medulloblastoma is between 60-80%, which remains far from ideal. While the molecular features of these tumors are being used to improve risk stratification, novel markers are needed to identify those at the greatest risk of recurrence and poor survival. MicroRNAs (miRNA) regulate gene expression and may play a major role in regulatory networks related to cancer therapy. Because of that, single nucleotide polymorphisms (SNPs) within these regions (miR-SNPs), which have the ability to alter normal miRNA function, are being evaluated in terms of cancer prognosis and survival. However, to our knowledge, miR-SNPs have not been evaluated in terms of outcomes (recurrence and survival) among those with pediatric medulloblastoma.

Methods: Patients with medulloblastoma (n = 100) treated at Texas Children's Cancer Center and MD Anderson Cancer Center between 1982 and 2009 who had existing genotype data from the Illumina Omni1 array were included in this analysis. We selected 25 miR-SNPs within 24 genes with a minor allele frequency (MAF) greater than 5%. Variants were selected from within pri- or pre-miRNAs, miRNA processing machinery, or within binding sites identified in the literature as related to tumorigenesis. The remaining variants were predicted to create or destroy miRNA binding sites per the prediction algorithm PolymiRTS 3.0. Adjusted hazard ratios (aHR) and 95% confidence intervals (CIs) were calculated using Cox regression under log-additive or dominant genetic models (if the MAF fell between 5-15%) to estimate the association between miR-SNPs and progression-free and overall survival (OS) times. All models were adjusted for sex (reference = male), race (reference = white), and age at diagnosis (continuous). Clinical variables including risk group, and craniospinal radiation were also analyzed. Multiple comparisons were adjusted for using the false discovery rate method.

Results: The median follow-up time among 88 survivors was 8.33 years (range 1.16 - 25.83 years). Individuals who carry a copy of the minor allele of KIAA0423 (rs1053667), which is located within a putative miR-19a/b binding site, experienced 2.93 times the hazard of progression (CC+CT vs. TT: aHR = 2.93; 95% CI: 1.10-7.83). For overall survival, carriers of a copy of the minor allele experienced 3.96 times the hazard of death (CC+CT vs. TT: aHR = 3.96; 95% CI: 1.12-14.02). While these data point to a potentially strong effect, the results did not remain significant after adjustment for multiple comparisons.

Conclusions: This preliminary analysis suggests that certain miR-SNPs may be associated with pediatric medulloblastoma recurrence and survival; however our findings must be validated in a larger population. Validated miR-SNPs may potentially be used for refined risk stratification for those diagnosed with childhood cancers or may be informative for targeted therapies.

Citation Format: Erin C. Peckham, Philip J. Lupo, Austin L. Brown, Mehmet Fatih Okcu, Ching C. Lau, Surya Rednam, Michael E. Scheurer. The role of germline microRNA-related polymorphisms on pediatric medulloblastoma prognosis and survival. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 853. doi:10.1158/1538-7445.AM2015-853

Prevalence and correlates of cell phone use among Texas drivers

Introduction

Cell phone use while driving restricts peripheral awareness and impairs reaction time. This study assessed the 3-year prevalence of cell phone use (CPU) of drivers and characteristics associated with its use in six cities across Texas, 2011–2013.

Methods

CPU and driver characteristics were observed among motor vehicles (n = 1280) stopped at major intersections in medical and academic campuses. A multivariable logistic regression model described the association between driver characteristics and CPU.

Results

The overall prevalence of any CPU was 18.7%. Any type of CPU and talking tended to decline, while texting seemed to increase from 2011 to 2013. CPU was more likely among female drivers (OR = 1.63; 95% CI = 1.21, 2.20), drivers < 25 years of age (OR = 4.12; 95% CI = 2.29, 7.39), and drivers without passengers (OR = 4.40; 95% CI = 2.82, 6.88).

Conclusion

Despite its dangers, CPU remains popular among Texas drivers. CPU and texting bans should target public health campaigns towards female and younger drivers.

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Cell phone use and drivers were observed in Texas medical and academic campuses.

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The overall prevalence of any cell phone use tended to decline from 2011 to 2013.

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Texting appeared to increase from 2011 to 2013.

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Cell phone use was more likely among females, those < 25 years and drivers alone.

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Cell phone use and texting bans should target females and younger drivers.

Distinct miRNA expression in dorsal striatal subregions is associated with risk for addiction in rats

Recently, we published data using an animal model that allowed us to characterize animals into two groups, addiction vulnerable and addiction resilient, where we identified that addiction/relapse vulnerability was associated with deficits in synaptic plasticity-associated gene expression in the dorsal striatum (DS). Notable was the strong reduction in expression for activity-regulated cytoskeleton-associated protein (Arc) considered a master regulator of synaptic plasticity. In the present study, we confirmed that Arc messenger RNA was significantly decreased in the DS, but importantly, we identified that this reduction was restricted to the dorsomedial (DMS) and not dorsolateral striatum (DLS). There is recent evidence of microRNA (miRNA)-associated posttranscriptional suppression of Arc and animal models of addiction have identified a key role for miRNA in the regulation of addiction-relevant genes. In further support of this link, we identified several differentially expressed miRNA with the potential to influence addiction-relevant plasticity genes, including Arc. A key study recently reported that miR-212 expression is protective against compulsive cocaine-seeking. Supporting this hypothesis, we found that miR-212 expression was significantly reduced in the DMS but not DLS of addiction-vulnerable animals. Together, our data provide strong evidence that miRNA promote ongoing plasticity deficits in the DS of addiction-vulnerable animals.

Longitudinal annoyance responses to a road traffic noise management strategy that reduced heavy vehicles at night

A traffic management strategy was designed to reduce trucks using an urban corridor. The intervention had potential to affect night-time truck flows, but did not target truck traffic in the day, or vehicles other than trucks at any hour. A two-year long panel study measured the community's response to this intervention, using five repeated measurements of response. There were significant reductions in the panel's response to noise, both for night-time annoyance and for interference with activities. This was remarkable given that noise monitoring showed that the intervention produced no change in conventional traffic noise indicators. However, there were measureable changes in the number of articulated truck movements at night, and the benefit can be attributed to reduction in the number of noise events from heavy vehicles. The parallel tracking of changes in reported noise effects and the numbers of heavy vehicles in the night hours in this longitudinal study provides strong support to the notion that noise effects at night depend on the number of noise events experienced, not only on the overall level of traffic noise. The latter appear to be unresponsive indicators by which to assess the noise-effect benefit of heavy vehicle reduction strategies.

Perceptual constancy in auditory perception of distance to railway tracks

Distance to a sound source can be accurately estimated solely from auditory information. With a sound source such as a train that is passing by at a relatively large distance, the most important auditory information for the listener for estimating its distance consists of the intensity of the sound, spectral changes in the sound caused by air absorption, and the motion-induced rate of change of intensity. However, these cues are relative because prior information/experience of the sound source-its source power, its spectrum and the typical speed at which it moves-is required for such distance estimates. This paper describes two listening experiments that allow investigation of further prior contextual information taken into account by listeners-viz., whether they are indoors or outdoors. Asked to estimate the distance to the track of a railway, it is shown that listeners assessing sounds heard inside the dwelling based their distance estimates on the expected train passby sound level outdoors rather than on the passby sound level actually experienced indoors. This form of perceptual constancy may have consequences for the assessment of annoyance caused by railway noise.

U.S. school travel, 2009 an assessment of trends

BACKGROUND

The White House Task Force on Childhood Obesity has set a goal of increasing walking and biking to school by 50% within 5 years. Meeting the goal requires a detailed understanding of the current patterns of school travel.

PURPOSE

To document nationally representative estimates of the amount of school travel and the modes used to access school in 2009 and compare these levels with 1969, 1995, and 2001.

METHODS

The National Household Travel Survey collected data on the travel patterns of 150,147 households in 2008 and 2009. Analyses, conducted in 2010, documented the time, vehicle miles traveled, and modes used by American students to reach school. A binary logit model assessed the influence of trip, child, and household characteristics on the decision to walk to school.

RESULTS

In 2009, 12.7% of K-8 students usually walked or biked to school compared with 47.7% in 1969. Rates of walking and biking to school were higher on the trip home from school in each survey year. During the morning peak period, school travel accounted for 5%-7% of vehicle miles traveled in 2009 and 10%-14% of all private vehicles on the road.

CONCLUSIONS

There have been sharp increases in driving children to school since 1969 and corresponding decreases in walking to school. This increase is particularly evident in the number of vehicle trips generated by parents dropping children at school and teens driving themselves. The NHTS survey provides a unique opportunity to monitor these trends in the future.

Tooth pulp inflammation increases brain-derived neurotrophic factor expression in rodent trigeminal ganglion neurons

Nociceptive pathways with first-order neurons located in the trigeminal ganglion (TG) provide sensory innervation to the head, and are responsible for a number of common chronic pain conditions, including migraines, temporomandibular disorders and trigeminal neuralgias. Many of those conditions are associated with inflammation. Yet, the mechanisms of chronic inflammatory pain remain poorly understood. Our previous studies show that the neurotrophin brain-derived neurotrophic factor (BDNF) is expressed by adult rat TG neurons, and released from cultured newborn rat TG neurons by electrical stimulation and calcitonin gene-related peptide (CGRP), a well-established mediator of trigeminal inflammatory pain. These data suggest that BDNF plays a role in activity-dependent plasticity at first-order trigeminal synapses, including functional changes that take place in trigeminal nociceptive pathways during chronic inflammation. The present study was designed to determine the effects of peripheral inflammation, using tooth pulp inflammation as a model, on regulation of BDNF expression in TG neurons of juvenile rats and mice. Cavities were prepared in right-side maxillary first and second molars of 4-week-old animals, and left open to oral microflora. BDNF expression in right TG was compared with contralateral TG of the same animal, and with right TG of sham-operated controls, 7 and 28 days after cavity preparation. Our ELISA data indicate that exposing the tooth pulp for 28 days, with confirmed inflammation, leads to a significant upregulation of BDNF in the TG ipsilateral to the affected teeth. Double-immunohistochemistry with antibodies against BDNF combined with one of nociceptor markers, CGRP or transient receptor potential vanilloid type 1 (TRPV1), revealed that BDNF is significantly upregulated in TRPV1-immunoreactive (IR) neurons in both rats and mice, and CGRP-IR neurons in mice, but not rats. Overall, the inflammation-induced upregulation of BDNF is stronger in mice compared to rats. Thus, mouse TG provides a suitable model to study molecular mechanisms of inflammation-dependent regulation of BDNF expression in vivo.

Response to a change in transport noise exposure: a review of evidence of a change effect

Environmental appraisals of transport infrastructure plans are generally conducted in situations where there will be a step change, or an abrupt change, in noise exposure. While there has been a number of studies of response to step changes in exposure, and seven previous reviews of subsets of these studies, understanding of human response to a change in noise exposure remains limited. Building largely on these previous reviews, this paper examines the evidence that when noise exposure is changed, subjective reaction may not change in the way that would be predicted from steady-state exposure-response relationships. The weight of evidence, while not incontrovertible, is that when exposure changes, responses show an excess response compared to responses predicted from steady-state exposure-response relationships. That is, there is a change effect in addition to an exposure effect--at least for road studies and at least where the change in exposure results from changes at the source. Further, there appears to be little, if any, adaptation of this excess response with time.

Response to a change in transport noise exposure: competing explanations of change effects

Annoyance response to a change in noise exposure appears to demonstrate an excess response relative to those predicted from exposure-response curves obtained under steady-state conditions. This change effect also appears to persist well after the change. Numerous explanations have been postulated for this phenomenon. This paper catalogs the different explanations and reviews the evidence for each. The evidence is of limited and variable quality but, while inadequate to endorse any one explanation, is sufficient to reject some notions and to identify a residual set of plausible explanations. These include two explanations based on modifiers of exposure-response relationships that potentially change between before and after conditions, an explanation based on differential response criteria of respondents chronically exposed to different steady-state levels of noise, and an explanation based on retention of coping strategies. All have ramifications for the assessment of human response (annoyance) where noise exposure changes, and some have wider implications for the interpretation of generalized exposure-response curves obtained in the steady state.

Pressure-polishing pipettes for improved patch-clamp recording

Pressure-polishing is a method for shaping glass pipettes for patch-clamp recording. We first developed this method for fabricating pipettes suitable for recording from small (<3 m) neuronal cell bodies. The basic principal is similar to glass-blowing and combines air pressure and heat to modify the shape of patch pipettes prepared by a conventional micropipette puller. It can be applied to so-called soft (soda lime) and hard (borosilicate) glasses. Generally speaking, pressure polishing can reduce pipette resistance by 25% without decreasing the diameter of the tip opening (Goodman and Lockery, 2000). It can be applied to virtually any type of glass and requires only the addition of a high-pressure valve and fitting to a microforge. This technique is essential for recording from ultrasmall cells (<5 m) and can also improve single-channel recording by minimizing pipette resistance. The blunt shape is also useful for perforated-patch clamp recording since this tip shape results in a larger membrane bleb available for perforation.

Patch clamp recording of ion channels expressed in Xenopus oocytes

Since its development by Sakmann and Neher (1, 2), the patch clamp has become established as an extremely useful technique for electrophysiological measurement of single or multiple ion channels in cells. This technique can be applied to ion channels in both their native environment and expressed in heterologous cells, such as oocytes harvested from the African clawed frog, Xenopus laevis. Here, we describe the well-established technique of patch clamp recording from Xenopus oocytes. This technique is used to measure the properties of expressed ion channels either in populations (macropatch) or individually (single-channel recording). We focus on techniques to maximize the quality of oocyte preparation and seal generation. With all factors optimized, this technique gives a probability of successful seal generation over 90 percent. The process may be optimized differently by every researcher based on the factors he or she finds most important, and we present the approach that have lead to the greatest success in our hands.

Making patch-pipettes and sharp electrodes with a programmable puller

Glass microelectrodes (also called pipettes) have been a workhorse of electrophysiology for decades. Today, such pipettes are made from glass capillaries using a programmable puller. Such instruments heat the capillary using either a metal filament or a laser and draw out the glass using gravity, a motor or both. Pipettes for patch-clamp recording are formed using only heat and gravity, while sharp electrodes for intracellular recording use a combination of heat, gravity, and a motor. The procedure used to make intracellular recording pipettes is similar to that used to make injection needles for a variety of applications, including cRNA injection into Xenopus oocytes. In general, capillary glass <1.2 mm in diameter is used to make pipettes for patch clamp recording, while narrower glass is used for intracellular recording (outer diameter = 1.0 mm). For each tool, the puller is programmed slightly differently. This video shows how to make both kinds of recording pipettes using pre-established puller programs.