Meaningful Work, Career Fit, and Professional Well-Being of Pediatric Academicians in the United States

OBJECTIVE

Examine associations between time spent in academic activities perceived as meaningful and professional well-being among academic pediatrics faculty.

METHODS

The sample comprised 248 full-time pediatric faculty (76% female, 81% white, non-Hispanic, 41% instructor or assistant professor) across the United States who completed an online survey in November 2019. Survey items included sociodemographic and professional characteristics, professional well-being measures (Stanford Professional Fulfillment Index; Maslach Burnout Inventory; Intention to Leave Academic Medicine), perceived meaningfulness of academic activities and assigned time to those activities. We defined global career fit as total percentage time assigned to professional activities considered meaningful by individuals, and activity-specific career fit as percentage time assigned to each meaningful professional activity.

RESULTS

As global career fit scores increased, professional fulfillment increased (r = 0.45, P < .001), whereas burnout (r = -0.29, P < .001) and intention to leave (r = -0.22, P < .001) decreased. Regarding activity-specific career fit, for individuals who considered patient care meaningful, as assigned time to patient care increased, professional fulfillment decreased (r = -0.14, P = .048) and burnout (r = 0.16, P = .02) and intention to leave (r = 0.26, P < .001) increased. There was no significant correlation between assigned time for teaching, research, or advocacy and professional well-being. Faculty were less likely to intend to leave academic medicine as assigned time increased for administrative or leadership activities if considered meaningful (r = -0.24, P = .01).

CONCLUSIONS

Time assigned to meaningful work activities may relate to professional well-being of academic pediatrics faculty. More time assigned to patient care, despite being meaningful, was associated with poor self-reported professional well-being. Effort allocation among diverse academic activities needs to be optimized to improve faculty well-being.

Post hospital admission blood lactate measurements are associated with mortality but not neurologic morbidity in children with cerebral malaria

BACKGROUND

In children with cerebral malaria (CM) admission blood lactate has previously guided intravenous fluid therapy and been validated as a prognostic biomarker associated with death. The usefulness of post-admission measurements of blood lactate in children with CM is less clear. The strength of association between blood lactate and neurological sequelae in CM survivors, as well as the optimal duration of post-admission measurements of blood lactate to identify children at higher risk of adverse outcomes is unknown.

METHODS

A retrospective cohort study of 1674 Malawian children with CM hospitalized from 2000 to 2018 who had blood lactate measurements every 6 h for the first 24 h after admission was performed. The strength of association between admission lactate or values measured at any time point in the first 24 h post-admission and outcomes (mortality and neurological morbidity in survivors) was estimated. The duration of time after admission that lactate remained a valid prognostic biomarker was assessed.

RESULTS

When lactate is analysed as a continuous variable, children with CM who have higher values at admission have a 1.05-fold higher odds (95% CI 0.99-1.11) of death compared to those with lower lactate values. Children with higher blood lactate at 6 h have 1.16-fold higher odds (95% CI 1.09-1.23) of death, compared to those with lower values. If lactate levels are dichotomized into hyperlactataemic (lactate > 5.0 mmol/L) or not, the strength of association between admission lactate and mortality increases (OR = 2.49, 95% CI 1.47-4.22). Blood lactate levels obtained after 18 h post-admission are not associated with outcomes. Similarly, the change in lactate concentrations through time during the first 24 h of hospital admission is not associated with outcomes. Blood lactate during hospitalization is not associated with adverse neurologic outcomes in CM survivors.

CONCLUSIONS

In children with CM, blood lactate is associated with death but not neurologic morbidity in survivors. To comprehensively estimate prognosis, blood lactate in children with CM should be assessed at admission and for 18 h afterwards.

Loss to Hospital Follow-Up in Pediatric Cerebral Malaria Survivors: A Case-Control Study

Children surviving central nervous system (CNS) infections are at high risk of neurological, behavioral, and cognitive sequalae. Early identification, characterization, and treatment of these sequelae may improve child and family health. In Africa, it is unclear if there are demographic or clinical factors that increase the risk of post-hospital loss to follow-up in children with CNS infections. If these factors exist, targeted educational efforts to increase rates of post-hospital retention could be focused on families at highest risk. We performed a case-control study of Malawian children with cerebral malaria, a locally common CNS infection, previously admitted to a specialized research unit in Blantyre, Malawi. Routine survivor post-hospital follow-up was scheduled for 1 month, 6 months, and 12 months. We compared demographic and clinical characteristics between 84 children who missed one or more of these post-hospital visits with 120 children who attended all visits. There were no statistically significant differences in demographic or clinical characteristics between children whose families returned for all follow-up visits and those who did not. Specifically, when comparing these groups, we found no differences in age (P = 00.646), sex (P = 0.789), duration of hospitalization (P = 0.903), distance from home to hospital (P = 0.355), type or severity of neurological sequelae (P = 0.837), guardian literacy (P = 0.057), or number of discharge medications (P = 0.464). No factors assessed in this study were associated with higher risk of loss to follow-up in Malawian child survivors of CNS infections. During hospitalization, educational efforts to increase post-hospital retention should focus on all families.

Health-related quality of life in a systematically assessed cohort of children and adults with urea cycle disorders

PURPOSE

Individuals with urea cycle disorders (UCDs) may develop recurrent hyperammonemia, episodic encephalopathy, and neurological sequelae which can impact Health-related Quality of Life (HRQoL). To date, there have been no systematic studies of HRQoL in people with UCDs.

METHODS

We reviewed HRQoL and clinical data for 190 children and 203 adults enrolled in a multicenter UCD natural history study. Physical and psychosocial HRQoL in people with UCDs were compared to HRQoL in healthy people and people with phenylketonuria (PKU) and diabetes mellitus. We assessed relationships between HRQoL, UCD diagnosis, and disease severity. Finally, we calculated sample sizes required to detect changes in these HRQoL measures.

RESULTS

Individuals with UCDs demonstrated worse physical and psychosocial HRQoL than their healthy peers and peers with PKU and diabetes. In children, HRQoL scores did not differ by diagnosis or severity. In adults, individuals with decreased severity had worse psychosocial HRQoL. Finally, we show that a large number of individuals would be required in clinical trials to detect differences in HRQoL in UCDs.

CONCLUSION

Individuals with UCDs have worse HRQoL compared to healthy individuals and those with PKU and diabetes. Future work should focus on the impact of liver transplantation and other clinical variables on HRQoL in UCDs.

Temporal Trends of Blood Glucose in Children with Cerebral Malaria

Hypoglycemia, defined as a blood glucose < 2.2 mmol/L, is associated with death in pediatric cerebral malaria (CM). The optimal duration of glucose monitoring in CM is unknown. We collected data from 1,674 hospitalized Malawian children with CM to evaluate the association between hypoglycemia and death or neurologic disability in survivors. We assessed the optimal duration of routine periodic measurements of blood glucose. Children with hypoglycemia at admission had a 2.87-fold higher odds (95% CI: 1.35-6.09) of death and, if they survived, a 3.21-fold greater odds (95% CI: 1.51-6.86) of sequelae at hospital discharge. If hypoglycemia was detected at 6 hours but not at admission, there was a 7.27-fold higher odds of death (95% CI: 1.85-8.56). The presence of newly developed hypoglycemia after admission was not independently associated with neurological sequelae in CM survivors. Among all new episodes of blood sugar below a treatment threshold of 3.0 mmol/L, 94.7% occurred within 24 hours of admission. In those with blood sugar below 3.0 mmol/L in the first 24 hours, low blood sugar persisted or recurred for up to 42 hours. Hypoglycemia at admission or 6 hours afterward is strongly associated with mortality in CM. Children with CM should have 24 hours of post-admission blood glucose measurements. If a blood glucose less than the treatment threshold of 3.0 mmol/L is not detected, routine assessments may cease. Children who have blood sugar values below the treatment threshold detected within the first 24 hours should continue to have periodic glucose measurements for 48 hours post-admission.

Clinical outcomes of children and adolescents with sickle cell disease and COVID-19 infection: A year in review at a metropolitan tertiary pediatric hospital

Background

COVID-19 was declared a global pandemic in March 2020. Early reports were primarily in adults, and sickle cell disease (SCD) was classified as a risk factor for severe COVID-19 disease. However, there are a limited number of primarily multi-center studies reporting on the clinical course of pediatric patients with SCD and COVID-19.

Methods

We conducted an observational study of all patients with SCD diagnosed with COVID-19 at our institution between March 31, 2020, and February 12, 2021. Demographic and clinical characteristics of this group were collected by retrospective chart review.

Results

A total of 55 patients were studied, including 38 children and 17 adolescents. Demographics, acute COVID-19 clinical presentation, respiratory support, laboratory findings, healthcare utilization, and SCD modifying therapies were comparable between the children and adolescents. Seventy-three percent (N = 40) of all patients required emergency department care or hospitalization. While 47% (N = 26) were hospitalized, only 5% (N = 3) of all patients required intensive care unit admission. Patients frequently had concurrent vaso-occlusive pain crisis (VOC) (N = 17, 43%) and acute chest syndrome (ACS) (N = 14, 35%). Those with ACS or an oxygen requirement had significantly higher white blood cell count, lower nadir hemoglobin, and higher D-dimers, supporting a pro-inflammatory and coagulopathic picture. Non-hospitalized patients were more likely to be on hydroxyurea than hospitalized patients (79 vs. 50%, p = 0.023).

Conclusion

Children and adolescent patients with SCD and acute COVID-19 often present with ACS and VOC pain requiring hospital-level care. Hydroxyurea treatment appears to be protective. We observed no mortality despite variable morbidity.

Changes in HDL cholesterol, particles, and function associate with pediatric COVID-19 severity

Background

Myriad roles for high-density lipoprotein (HDL) beyond atheroprotection include immunologic functions implicated in the severity of coronavirus disease-2019 (COVID-19) in adults. We explored whether there is an association between HDL and COVID-19 severity in youth.

Methods

A pediatric cohort (N = 102), who tested positive for COVID-19 across a range of disease manifestations from mild or no symptoms, to acute severe symptoms, to the multisystem inflammatory syndrome of children (MIS-C) was identified. Clinical data were collected from the medical record and reserve plasma aliquots were assessed for lipoproteins by NMR spectroscopy and assayed for HDL functional cholesterol efflux capacity (CEC). Findings were compared by COVID-19 status and symptom severity. Lipoprotein, NMR spectroscopy and CEC data were compared with 30 outpatient COVID negative children.

Results

Decreasing HDL cholesterol (HDL-c), apolipoprotein AI (ApoA-I), total, large and small HDL particles and HDL CEC showed a strong and direct linear dose-response relationship with increasing severity of COVID-19 symptoms. Youth with mild or no symptoms closely resembled the uninfected. An atypical lipoprotein that arises in the presence of severe hepatic inflammation, lipoprotein Z (LP-Z), was absent in COVID-19 negative controls but identified more often in youth with the most severe infections and the lowest HDL parameters. The relationship between HDL CEC and symptom severity and ApoA-I remained significant in a multiply adjusted model that also incorporated age, race/ethnicity, the presence of LP-Z and of GlycA, a composite biomarker reflecting multiple acute phase proteins.

Conclusion

HDL parameters, especially HDL function, may help identify youth at risk of more severe consequences of COVID-19 and other novel infectious pathogens.

First STEPS: Primary Outcomes of a Randomized, Stepped-Care Behavioral Clinical Trial for Parents of Young Children With New-Onset Type 1 Diabetes

OBJECTIVE

Despite the emotional challenges of parental adjustment to a child's type 1 diabetes diagnosis and the unique complexities of early childhood, there are few programs designed to meet the needs of parents of young children at new onset. This study evaluated First STEPS (Study of Type 1 in Early childhood and Parenting Support), a stepped-care behavioral intervention designed to support parents' psychosocial functioning and promote children's glycemic outcomes.

RESEARCH DESIGN AND METHODS

Using a two-site randomized clinical trial design, parents (n = 157) of children aged 1-6 years completed baseline data within 2 months of diabetes diagnosis and were randomly assigned to intervention (n = 115) or usual care (n = 42) for 9 months. Intervention steps included: 1) peer parent coaching, with step-ups to 2) structured behavioral counseling and 3) professional consultations with a diabetes educator and psychologist, based on parent mood and child HbA1c. Participants completed follow-ups at 9 and 15 months postrandomization. Primary outcomes were parent depressive symptoms and child HbA1c.

RESULTS

Depressive symptoms improved in both groups, and intervention parents had significantly lower depressive symptoms at the 9- and 15-month follow-ups compared with usual care. HbA1c decreased in both groups, but there were no between-group differences at 9 or 15 months.

CONCLUSIONS

First STEPS improved parents' mood following young children's type 1 diabetes diagnosis. Results indicate likely benefits of parent coach support, supplemented by intervention intensifications, including behavioral intervention and diabetes education. This model has high potential for patient engagement. The absence of a medical intervention component may explain null findings for HbA1c; incorporating targeted behavioral support for intensive diabetes treatment may maximize intervention impact.

The prostate tissue‐based telomere biomarker as a prognostic tool for metastasis and death from prostate cancer after prostatectomy

Current biomarkers are inadequate prognostic predictors in localized prostate cancer making treatment decision‐making challenging. Previously, we observed that the combination of more variable telomere length among prostate cancer cells and shorter telomere length in prostate cancer‐associated stromal cells – the telomere biomarker – is strongly associated with progression to metastasis and prostate cancer death after prostatectomy independent of currently used pathologic indicators. Here, we optimized our method allowing for semi‐automated telomere length determination in single cells in fixed tissue, and tested the telomere biomarker in five cohort studies of men surgically treated for clinically localized disease (N = 2,255). We estimated the relative risk (RR) of progression to metastasis (N = 311) and prostate cancer death (N = 85) using models appropriate to each study's design adjusting for age, prostatectomy stage, and tumor grade, which then we meta‐analyzed using inverse variance weights. Compared with men who had less variable telomere length among prostate cancer cells and longer telomere length in prostate cancer‐associated stromal cells, men with the combination of more variable and shorter telomere length had 3.76 times the risk of prostate cancer death (95% confidence interval [CI] 1.37–10.3, p = 0.01) and had 2.23 times the risk of progression to metastasis (95% CI 0.99–5.02, p = 0.05). The telomere biomarker was associated with prostate cancer death in men with intermediate risk disease (grade groups 2/3: RR = 9.18, 95% CI 1.14–74.0, p = 0.037) and with PTEN protein intact tumors (RR = 6.74, 95% CI 1.46–37.6, p = 0.015). In summary, the telomere biomarker is robust and associated with poor outcome independent of current pathologic indicators in surgically treated men.

An educational intervention to facilitate appropriate subspecialty referrals: a study assessing resident communication skills

BACKGROUND

Our goal was to improve pediatric residents' advanced communication skills in the setting of referral to address the entrustable professional activity of subspecialty referral identified by the American Board of Pediatrics. To accomplish this aim, we created a referral and consultation curriculum to teach and assess core communication skills in subspecialty referral involving an adolescent with syncope, an anxiety-provoking symptom that is rarely associated with serious pathology.

METHODS

We utilized blended multimodal educational interventions to improve resident communication skills in referral of patients. Trainees participated in 1) an interactive online module on syncope focusing on "red-flag" symptoms that would warrant a subspecialty cardiology referral and 2) a 4-h intervention with Standardized Parents (SPs), focusing on the case-based application of communication skills. Communication skills were assessed by two pre- and post- Objective Structured Clinical Examination encounters of patients with syncope, with an SP evaluation using a 20-item checklist. Analysis was performed with Sign test and McNemar's test. Trainees provided feedback on a Critical Incident Questionnaire, which was analyzed qualitatively.

RESULTS

Sixty-four residents participated. There was an overall improvement in communication skills based on SP scores (82.7 ± 10.9% to 91.7 ± 5.0%, p < 0.001), and 13/20 items demonstrated significant improvement post-intervention. Residents' improved performance enabled them to address patient/family emotions, explain referral logistics, and clarify concerns to agree on a plan.

CONCLUSIONS

By participating in this curriculum, residents' communication skills improved immediately post-intervention. Further research is needed to assess if this intervention improves patient care by providing residents with enduring skills to judiciously manage the referral process.

Multinational Analysis of Children Transfused With Pathogen Inactivated Platelets

BACKGROUND

Pathogen inactivated (PI) platelets are a technological advancement in blood safety; however, the pediatric experience is not well characterized. We studied pediatric patients who received transfusions of PI platelets across several centers and countries to determine if transfusion reaction rates differed when compared with conventional platelets.

METHODS

This is a retrospective multisite study conducted during 2 time periods. The study period started at the time each site began using PI platelets on a widespread basis, and the control period was a similar timespan before PI introduction. Suspected acute transfusion reactions were compared.

RESULTS

The study included 3839 pediatric patients who were 0 to 18 years of age who received >7930 platelet transfusions, in total, across 4 centers in 3 countries between 2013 and 2019. The age distribution of patients in the study and control period was not significantly different (P = .190). There was not a difference in the percentage of patients who had any type of transfusion reaction between the time periods (1.0% and 1.1%, P = .803). There were fewer patients with mild allergic reactions in the study period compared with the control period (0.2% and 0.7% of patients with reactions, respectively, P = .018).

CONCLUSIONS

Pediatric patients have the same rate of acutely suspected transfusion reactions when receiving PI or conventional platelet transfusions. Subgroup analysis found fewer mild allergic reactions in the study period, which was contemporaneous to the addition of using platelet additive solution more broadly. Future studies of PI platelets should include children to better assess transfusion efficacy and hemostatic outcomes.

Natural and anthropogenic noise increase vigilance and decrease foraging behaviors in song sparrows

Animals glean information about risk from their habitat. The acoustic environment is one such source of information, and is an important, yet understudied ecological axis. Although anthropogenic noise has become recently ubiquitous, risk mitigation behaviors have likely been shaped by natural noise over millennia. Listening animals have been shown to increase vigilance and decrease foraging in both natural and anthropogenic noise. However, direct comparisons could be informative to conservation and understanding evolutionary drivers of behavior in noise. Here, we used 27 song sparrows (Melospiza melodia) and 148 laboratory behavioral trials to assess foraging and vigilance behavior in both anthropogenic and natural noise sources. Using five acoustic environments (playbacks of roadway traffic, a whitewater river, a whitewater river shifted upwards in frequency, a river with the amplitude modulation of roadway traffic, and an ambient control), we attempt to parse out the acoustic characteristics that make a foraging habitat risky. We found that sparrows increased vigilance or decreased foraging in 4 of 6 behaviors when foraging in higher sound levels regardless of the noise source or variation in frequency and amplitude modulation. These responses may help explain previously reported declines in abundance of song sparrows exposed to playback of intense river noise. Our results imply that natural soundscapes have likely shaped behavior long before anthropogenic noise, and that high sound levels negatively affect the foraging-vigilance trade-off in most intense acoustic environments. Given the ever-increasing footprint of noise pollution, these results imply potential negative consequences for bird populations.

Lipid-Lowering Drug Use and Cancer Incidence and Mortality in the ARIC Study

Background

Lipid-lowering drugs, particularly statins, are associated with reduced incidence of certain cancers in some studies. Associations with cancer mortality are not well studied, and whether associations are similar across race is unknown.

Methods

We conducted a prospective analysis of 12 997 cancer-free participants in the Atherosclerosis Risk in Communities Study who were never users at visit 1 (1987-1989). Ever use, duration of use, and age at first use were modeled as time-dependent variables using Cox regression to estimate associations with total, obesity- and smoking-associated, bladder, breast, colorectal, lung, and prostate cancer incidence and mortality.

Results

We ascertained 3869 cancer cases and 1661 cancer deaths in 237 999 or more person-years. At 6 years of follow-up, 70.8% of lipid-lowering drug use was a statin. Compared with never use, ever use was associated with lower total, obesity- and smoking-associated cancer mortality and with colorectal cancer mortality (hazard ratio [HR] = 0.50, 95% confidence interval [CI] = 0.32 to 0.79) and incidence (HR = 0.69, 95% CI = 0.53 to 0.92). Inverse associations were consistent by sex and race. Shorter-term use was associated with bladder cancer incidence in men (<10 years: HR = 1.67, 95% CI = 1.02 to 2.73). First use at age 60 years or older was inversely associated with: total mortality, obesity- and smoking-associated mortality, and colorectal cancer mortality; and total incidence, obesity- and smoking-associated incidence, and breast, colorectal, and prostate cancer incidence.

Conclusions

This study provides additional evidence for inverse associations between lipid-lowering drug use and cancer incidence and mortality but a positive association with bladder cancer incidence in men. Evaluation of the impact of chemoprevention strategies that include lipid-lowering drugs on population-level cancer burden is needed.

Predictors of mood, diabetes-specific and COVID-19-specific experiences among parents of early school-age children with type 1 diabetes during initial months of the COVID-19 pandemic

OBJECTIVE

The current study explored pre-pandemic sociodemographics, medical characteristics, social/family support, and mood symptoms, and current COVID-19 experiences as predictors of mood, positive/negative diabetes-specific experiences, and COVID-19-specific distress among parents of children with type 1 diabetes during the COVID-19 pandemic. We hypothesized that parents from marginalized backgrounds, youth with higher pre-pandemic A1c and no CGM use, parents with lower pre-pandemic social/family support and more pre-pandemic mood/anxiety symptoms, and those with more negative COVID-19 experiences would have more depressive symptoms, fewer positive and more negative diabetes-specific experiences, and more COVID-19-specific distress during the initial months of the pandemic.

RESEARCH DESIGN AND METHODS

Participants were parents of early school-age children with type 1 diabetes (n = 100; 65% non-Hispanic, white, 92% mothers, 75% married; M_{child age}  = 6.74 ± 1.59 years) who had completed a behavioral intervention trial ≥6 months ago and were re-contacted in June/July 2020 to report on their COVID-19 pandemic experiences and parent psychosocial outcomes. Pre-pandemic parent mood/anxiety symptoms, family/social support, and children's medical characteristics (CGM use; M_A1C  = 8.17% ± 1.40%) were assessed M = 1.45 ± 0.59 years prior.

RESULTS

More pre-pandemic social support predicted fewer depressive symptoms, more positive diabetes-specific experiences, and less COVID-19-specific distress during the pandemic. More pre-pandemic depressive symptoms predicted more depressive symptoms during the pandemic. More life disruptions due to the pandemic were associated with more negative diabetes-specific experiences and more COVID-19-specific distress. Parents of color had more negative diabetes-specific experiences.

CONCLUSIONS

Social support may be particularly important to assess and address through intervention. Pediatric diabetes care providers should monitor parent experiences in relation to children's diabetes management. ClinicalTrials.gov identifier: NCT02527525.

Obesity is Associated with Shorter Telomere Length in Prostate Stromal Cells in Men with Aggressive Prostate Cancer

In our prior studies, obesity was associated with shorter telomeres in prostate cancer-associated stromal (CAS) cells, and shorter CAS telomeres were associated with an increased risk of prostate cancer death. To determine whether the association between obesity and shorter CAS telomeres is replicable, we conducted a pooled analysis of 790 men who were surgically treated for prostate cancer, whose tissue samples were arrayed on five tissue microarray (TMA) sets. Telomere signal was measured using a quantitative telomere-specific FISH assay and normalized to 4',6-diamidino-2-phenylindole for 351 CAS cells (mean) per man; men were assigned their median value. Weight and height at surgery, collected via questionnaire or medical record, were used to calculate body mass index (BMI; kg/m²) and categorize men as normal (<25), overweight (25 ≤ BMI < 30), or obese (≥30). Analyses were stratified by grade and stage. Men were divided into tertiles of TMA- (overall) or TMA- and disease aggressiveness- (stratified) specific distributions; short CAS telomere status was defined by the bottom two tertiles. We used generalized linear mixed models to estimate the association between obesity and short CAS telomeres, adjusting for age, race, TMA set, pathologic stage, and grade. Obesity was not associated with short CAS telomeres overall, or among men with nonaggressive disease. Among men with aggressive disease (Gleason≥4+3 and stage>T2), obese men had a 3-fold increased odds of short CAS telomeres (OR: 3.06; 95% confidence interval: 1.07-8.75; P _trend = 0.045) when compared with normal weight men. Telomere shortening in prostate stromal cells may be one mechanism through which lifestyle influences lethal prostate carcinogenesis. PREVENTION RELEVANCE: This study investigates a potential mechanism underlying the association between obesity and prostate cancer death. Among men with aggressive prostate cancer, obesity was associated with shorter telomeres prostate cancer associated stromal cells, and shorter CAS telomeres have been associated with an increased risk of prostate cancer death.

Influence of the Turing instability on the motion of domain boundaries

Turing's theory of pattern formation has provided crucial insights into the behavior of various biological, geographical, and chemical systems over the last few decades. Existing studies have focused on moving-boundary Turing systems for which the motion of the boundary is prescribed by an external agent. In this paper, we present an extension of this theory to a class of systems in which the front motion is governed by the physical processes that occur within the domain. Biological systems exhibiting apically dominant growth and corrosion of metals and alloys highlight some of the noteworthy examples of such systems. In this study, we characterize the nature of interaction between the moving front and the Turing-instability for both an activator-inhibitor and an activator-substrate model. Behavioral regimes of periodic, as well as nonperiodic (nonconstant), growth rates are obtained. Furthermore, the trends in the first show striking similarities with the cyclic-boundary-kinetics observed in experimental systems. In general, a stationary, periodic structure is also left behind the moving front. If the periodicity of the boundary kinetics agrees with the allowed range of the stable-periodic solutions, the pattern formed tends to persist. Otherwise, it evolves to a nearby energy-minimum either by peak-splitting, peak-decay, or by settling down to a spatially homogeneous state.

Abstract 2357: Lipid-lowering drug use, duration of use, and age at first use is associated with a lower risk of colorectal cancer mortality in men and women in the Atherosclerosis Risk in Communities (ARIC) Study

Background: While lipid-lowering drugs, particularly statins, are associated with a modestly reduced risk of developing colorectal cancer (CRC), the association of lipid-lowering drug use, duration of use, and age at first use with CRC mortality in men and women without the diagnosis at baseline, has not been well studied. Further, whether associations are similar across race is unknown. Thus, we aimed to characterize the association between lipid-lowering drug use and CRC mortality in men and women and by race. We classified lipid-lowering drug use in a time-dependent manner as current use, duration of use, and age at first use.

Methods: We conducted a prospective cohort study of 14,428 cancer-free men and women attending visit 2 (1990-1992) of the Atherosclerosis Risk in Communities (ARIC) Study. Death from CRC was ascertained from the underlying cause on death certificates. Follow-up began at visit 2 and ended at date of death or 12/31/2015, whichever came first. There were 384 incident CRC cases and 144 deaths in 290,249 person-years. Cox regression was used to estimate relative hazards (HR) and 95% confidence intervals (CI) for CRC incidence and death adjusting for age, sex, education, race and field center, BMI, smoking status and pack years, alcohol use, red and processed meat consumption, aspirin use, and family history of any cancer and family history of CRC overall and by gender and race. Current lipid-lowering medication use, duration of use (&lt;15 years, ≥15 years), and age at first use (&lt;50, 50-59, 60-69, and ≥70 years of age) were modeled as time-dependent variables.

Results: Mean age was 57 years and mean BMI was 28.1 kg/m2; 54.9% were women and 27.9% were Black. By visit 4 (1996-98), after an average of 6 years of follow-up, 22% of participants were using lipid-lowering drugs. Compared to never users, current use was associated with 53% lower risk of CRC death (HR 0.47; 95%CI 0.32-0.71). Inverse associations were present in both men (HR 0.59; 95%CI 0.35-0.99) and women (HR 0.37; 95%CI 0.20-0.69) and in Black (HR 0.44; 95%CI 0.19-1.00) and White (HR 0.49; 95%CI 0.31-0.77) participants. Inverse associations were consistent across different patterns of duration of use and was inverse irrespective of age at first use. Current use was also associated with a lower risk of CRC incidence (HR: 0.72; 95%CI 0.57-0.92).

Conclusions: Current use of lipid-lowering drugs was associated with a statistically significant lower risk of dying from CRC in participants without cancer at baseline, including men and women and in Black and white participants, irrespective of the duration (15 year intervals) or age at first use.

Support: NHLBI contracts, NCI grants, NPCR

Citation Format: Michael T. Marrone, John R. Barber, Alison M. Mondul, Anna E. Prizment, David Couper, Corinne E. Joshu, Elizabeth A. Platz. Lipid-lowering drug use, duration of use, and age at first use is associated with a lower risk of colorectal cancer mortality in men and women in the Atherosclerosis Risk in Communities (ARIC) Study [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2357.

The association between serum sex steroid hormone concentrations and intraprostatic inflammation in men without prostate cancer and irrespective of clinical indication for biopsy in the placebo arm of the Prostate Cancer Prevention Trial

BACKGROUND

Intraprostatic inflammation is an emerging prostate cancer risk factor. Estrogens are pro-inflammatory while androgens are anti-inflammatory. Thus, we investigated whether serum sex steroid hormone concentrations are associated with intraprostatic inflammation to inform mechanistic links among hormones, inflammation, and prostate cancer.

METHODS

We conducted a cross-sectional study among 247 men in the placebo arm of the Prostate Cancer Prevention Trial who had a negative end-of-study biopsy, most (92.7%) performed without clinical indication per trial protocol. Serum estradiol, estrone, and testosterone were previously measured by immunoassay in pooled baseline and Year 3 serum. Free estradiol and free testosterone were calculated. Inflammation was visually assessed (median of three prostate biopsy cores per man). Polytomous or logistic regression was used to estimate the odds ratio (OR) and 95% confidence interval (CI) of some or all cores inflamed (both vs none) or any core inflamed (vs none) by hormone tertile, adjusting for age, race, and family history. We evaluated effect modification by waist circumference and body mass index (BMI).

RESULTS

In all, 51.4% had some and 26.3% had all cores inflamed. Free (P-trend = .11) but not total estradiol was suggestively inversely associated with all cores inflamed. In men with waist circumference greater than or equal to 102 cm (P-trend = .021) and BMI ≥ 27.09 kg/m² (P-trend = .0037) free estradiol was inversely associated with any core inflamed. Estrone was inversely associated with all cores inflamed (T3: OR = 0.36, 95% CI 0.14-0.95, P-trend = .036). Total (T3: OR = 1.91, 95% CI 0.91-4.02, P-trend = .11) and free (T3: OR = 2.19, 95% CI 1.01-4.74, P-trend = .05) testosterone were positively associated with any core inflamed, especially free testosterone in men with waist circumference less than 102 cm (T3: OR = 3.51, 95% CI 1.03-12.11, P-trend = .05).

CONCLUSIONS

In this first study in men without prostate cancer and irrespective of clinical indication for biopsy, contrary to the hypothesis, circulating estrogens appeared to be inversely associated, especially in heavy men, whereas androgens appeared to be positively associated with intraprostatic inflammation.

Clinical stage provides useful prognostic information even after pathological stage is known for prostate cancer in the PSA era

BACKGROUND

Pathological and clinical stage are associated with prostate cancer-specific survival after prostatectomy. With PSA screening, the post-surgery prognostic utility of clinical stage is debatable in studies seeking to identify new biomarkers. Few studies have investigated clinical stage and lethal prostate cancer association after accounting for pathological stage. We hypothesize that clinical stage provides prognostic information beyond pathological stage in the PSA era.

METHODS

Cox regression models tested associations between clinical and pathological stage and lethal prostate cancer among 3,064 participants from the Health Professionals Follow-Up Study and Physicians' Health Study (HPFS/PHS) who underwent prostatectomy. Likelihood ratio tests and c-statistics were used to assess the models' prognostic utility. Equivalent analyses were performed in 16,134 men who underwent prostatectomy at Johns Hopkins.

RESULTS

Independently, clinical and pathological stage were associated (p<0.0001 for both) with rate of lethal prostate cancer in HPFS/PHS. The model with clinical and pathological stage fit significantly better than the model with only pathological stage in all men (p = 0.01) and in men diagnosed during the PSA era (p = 0.04). The mutually adjusted model also improved discriminatory ability. In the Johns Hopkins cohort, the model with clinical and pathological stage improved discriminatory ability and fit significantly better overall (p<0.0001) and in the PSA era (p<0.0001).

CONCLUSIONS

Despite stage migration resulting from widespread PSA screening, clinical stage remains associated with progression to lethal prostate cancer independent of pathological stage. Future studies evaluating associations between new factors and poor outcome following prostatectomy should consider including both clinical and pathological stages since the data is already available.

High Extratumoral Mast Cell Counts Are Associated with a Higher Risk of Adverse Prostate Cancer Outcomes

BACKGROUND

Given our previous findings that low intratumoral and high extratumoral mast cell numbers are associated with higher risk of biochemical recurrence after radical prostatectomy, we now assessed this relationship with race and the development of metastases.

METHODS

We stained for mast cell tryptase via IHC and fluorescent immunolabeling in 885 men across multiple tissue microarray sets designed to assess biomarkers in association with race and prostate cancer outcomes (median follow-up, 7.0 years).

RESULTS

Intratumoral and extratumoral mast cell counts were significantly lower in tissues from African-American compared with European-American men, but not within strata of cancer grade. There was no association between mast cell counts and ERG positivity, PTEN loss, or TP53 missense mutation. Higher minimum extratumoral mast cells were associated with an increased risk of biochemical recurrence [comparing highest with lowest tertiles: HR, 1.61; 95% confidence interval (CI), 1.12-2.29; P trend = 0.01]; this pattern was similar among European-American and African-American men and by grade of disease. There was no significant association between minimum intratumoral mast cell count and biochemical recurrence, overall or within strata of race and grade. Finally, high minimum number of extratumoral mast cells was associated with prostate cancer metastases (comparing highest with lowest tertiles: HR, 2.12; 95% CI, 1.24-3.63; P trend = 0.01).

CONCLUSIONS

High extratumoral mast cell numbers are associated with biochemical recurrence and the development of metastases after radical prostatectomy.

IMPACT

Higher numbers of benign tissue mast cells are associated with a higher risk of adverse outcomes after radical prostatectomy, including metastatic prostate cancer.

Racial Difference in Prostate Cancer Cell Telomere Lengths in Men with Higher Grade Prostate Cancer: A Clue to the Racial Disparity in Prostate Cancer Outcomes

BACKGROUND

Black men have worse prostate cancer outcomes following treatment than White men even when accounting for prognostic factors. However, biological explanations for this racial disparity have not been fully identified. We previously showed that more variable telomere lengths among cancer cells and shorter telomere lengths in cancer-associated stromal (CAS) cells individually and together ("telomere biomarker") are associated with prostate cancer-related death in surgically treated men independent of currently used prognostic indicators. Here, we hypothesize that Black-White differences in the telomere biomarker and/or in its components may help explain the racial disparity in prostate cancer outcomes.

METHODS

Black [higher grade (Gleason ≥4+3) = 34 and lower grade = 93] and White (higher grade = 34 and lower grade = 89) surgically treated men were frequency matched on age, pathologic stage, and grade. We measured telomere lengths in cancer and CAS cells using a robust telomere-specific FISH assay. Tissue microarray and grade-specific distributional cutoff points without regard to race were evaluated.

RESULTS

Among men with higher grade disease, the proportion of Black men (47.1%) with more variable cancer cell telomere lengths was 2.3-times higher (P = 0.02) than that in White men (20.6%). In contrast, among men with lower grade disease, cancer cell telomere length variability did not differ by race. The proportion of men with shorter CAS cell telomeres did not differ by race for either higher or lower grade disease.

CONCLUSIONS

A greater proportion of Black men with higher grade disease have an adverse prostate cancer cell telomere phenotype than White men with higher grade disease.

IMPACT

Our findings suggest a possible explanation for the racial disparity in prostate cancer outcomes.

SES and correlated factors do not explain the association between periodontal disease, edentulism, and cancer risk

PURPOSE

Severe periodontal disease and edentulism have been previously reported to be significantly associated with cancer risk and mortality, including in the Atherosclerosis Risk in Communities study (2018); however, complex sources of confounding by socioeconomic status (SES), and characteristics correlated with SES, could have been present in earlier analyses.

METHODS

To capture life course SES and its correlates, we generated a propensity score and included it, along with other potential confounders such as smoking and obesity, into a Cox regression model to examine the association between periodontal disease and cancer risk. In addition, we stratified the model with the propensity score by low and high SES. All statistical tests were two-sided.

RESULTS

Compared with our previous study, the associations for severe periodontitis and cancer incidence remained comparable after weighting by the propensity score (e.g., for total cancer: before weighting, hazard ratio = 1.24, 95% confidence interval = 1.07-1.42 vs. after weighting, hazard ratio = 1.23, 95% confidence interval = 1.05-1.44 when comparing severe periodontitis to no or mild periodontitis). Associations were comparable in low and high SES strata and statistically significant among participants with high SES.

CONCLUSIONS

Complex sources of confounding by SES and its correlates are unlikely to fully account for the positive associations observed for periodontal disease and edentulism and cancer risk.

Phylogenomics resolves major relationships and reveals significant diversification rate shifts in the evolution of silk moths and relatives

BACKGROUND

Silkmoths and their relatives constitute the ecologically and taxonomically diverse superfamily Bombycoidea, which includes some of the most charismatic species of Lepidoptera. Despite displaying spectacular forms and diverse ecological traits, relatively little attention has been given to understanding their evolution and drivers of their diversity. To begin to address this problem, we created a new Bombycoidea-specific Anchored Hybrid Enrichment (AHE) probe set and sampled up to 571 loci for 117 taxa across all major lineages of the Bombycoidea, with a newly developed DNA extraction protocol that allows Lepidoptera specimens to be readily sequenced from pinned natural history collections.

RESULTS

The well-supported tree was overall consistent with prior morphological and molecular studies, although some taxa were misplaced. The bombycid Arotros Schaus was formally transferred to Apatelodidae. We identified important evolutionary patterns (e.g., morphology, biogeography, and differences in speciation and extinction), and our analysis of diversification rates highlights the stark increases that exist within the Sphingidae (hawkmoths) and Saturniidae (wild silkmoths).

CONCLUSIONS

Our study establishes a backbone for future evolutionary, comparative, and taxonomic studies of Bombycoidea. We postulate that the rate shifts identified are due to the well-documented bat-moth "arms race". Our research highlights the flexibility of AHE to generate genomic data from a wide range of museum specimens, both age and preservation method, and will allow researchers to tap into the wealth of biological data residing in natural history collections around the globe.

Telomere alterations in neurofibromatosis type 1-associated solid tumors

The presence of Alternative lengthening of telomeres (ALT) and/or ATRX loss, as well as the role of other telomere abnormalities, have not been formally studied across the spectrum of NF1-associated solid tumors. Utilizing a telomere-specific FISH assay, we classified tumors as either ALT-positive or having long (without ALT), short, or normal telomere lengths. A total of 426 tumors from 256 NF1 patients were evaluated, as well as 99 MPNST tumor samples that were sporadic or of unknown NF1 status. In the NF1-glioma dataset, ALT was present in the majority of high-grade gliomas: 14 (of 23; 60%) in contrast to only 9 (of 47; 19%) low-grade gliomas (p = 0.0009). In the subset of ALT-negative glioma cases, telomere lengths were estimated and we observed 17 (57%) cases with normal, 12 (40%) cases with abnormally long, and only 1 (3%) case with short telomeres. In the NF1-associated malignant nerve sheath tumor (NF1-MPNST) set (n = 75), ALT was present in 9 (12%). In the subset of ALT-negative NF1-MPNST cases, telomeres were short in 9 (38%), normal in 14 (58%) and long in 1 (3%). In the glioma set, overall survival was significantly decreased for patients with ALT-positive tumors (p < 0.0001). In the NF1-MPNST group, overall survival was superior for patients with tumors with short telomeres (p = 0.003). ALT occurs in a subset of NF1-associated solid tumors and is usually restricted to malignant subsets. In contrast, alterations in telomere lengths are more prevalent than ALT.

Age-Specific Serum Total and Free Estradiol Concentrations in Healthy Men in US Nationally Representative Samples

Purpose

To report age-specific serum estradiol concentration in nonsmoking, lean US men without comorbidities. We provide concentrations from 30 and 15 to 20 years ago given previously described declines in serum estradiol in US men over time.

Methods

We used data from the Third National Health and Nutrition Examination Survey (NHANES III; 1988 to 1991) and continuous NHANES (1999 to 2004). Serum estradiol and SHBG were previously measured by competitive electrochemiluminescence immunoassays. Free estradiol was estimated from estradiol, SHBG, and albumin. By age, we calculated median concentrations overall and for nonsmoking, lean (body mass index <25 kg/m² and waist <102 cm) men without diabetes, cardiovascular disease, or cancer.

Results

Overall, respective total estradiol medians for men ages 20 to 39, 40 to 59, and ≥60 years old were 37.0, 33.9, and 33.5 pg/mL in NHANES III and 31.3, 30.5, and 27.0 pg/mL in continuous NHANES. In nonsmoking, lean men without comorbidities, respective total estradiol medians were 32.0, 32.1, and 32.0 pg/mL in NHANES III and 29.1, 22.7, and 26.1 pg/mL in continuous NHANES. Overall, respective free estradiol medians were 0.82, 0.72, and 0.64 pg/mL in NHANES III and 0.67, 0.61, and 0.47 pg/mL in continuous NHANES. In nonsmoking, lean men without comorbidities, respective free estradiol medians were 0.64, 0.67, and 0.62 pg/mL in NHANES III and 0.58, 0.42, and 0.40 pg/mL continuous NHANES.

Conclusion

We report US nationally representative serum estradiol concentrations in healthy men, which could be used for targeting estradiol during testosterone supplementation and for general good health.

Periodontal Disease Assessed Using Clinical Dental Measurements and Cancer Risk in the ARIC Study

Background

While evidence is increasingly consistent with a positive association between periodontitis and cancer risk, most studies have relied on self-reported periodontitis. In this study, we prospectively evaluated the association of periodontal disease severity with cancer risk in black and white older adults in a cohort study that included a dental examination.

Methods

Included were 7466 participants in the Atherosclerosis Risk in Communities study cohort who at visit 4 (1996-1998) reported being edentulous or underwent the dental examination. Probing depth and gingival recession were measured at six sites on all teeth; these measurements were used to define periodontal disease severity. Incident cancers (n = 1648) and cancer deaths (n = 547) were ascertained during a median of 14.7 years of follow-up. All statistical tests were two-sided.

Results

An increased risk of total cancer (hazard ratio [HR] = 1.24, 95% confidence interval [CI] = 1.07 to 1.44, Ptrend = .004) was observed for severe periodontitis (>30% of sites with attachment loss >3 mm) compared with no/mild periodontitis (<10% of sites with attachment loss >3 mm), adjusting for smoking and other factors. Strong associations were observed for lung cancer (HR = 2.33, 95% CI = 1.51 to 3.60, Ptrend < .001), and elevated risks were noted for colorectal cancer for severe periodontitis, which were significant among never smokers (HR = 2.12, 95% CI = 1.00 to 4.47). Associations were generally weaker, or not apparent among black participants, except for lung and colorectal cancers, where associations were similar by race. No associations were observed for breast, prostate, or hematopoietic and lymphatic cancer risk.

Conclusions

This study provides additional evidence that cancer risk, especially for lung and colorectal cancer, is elevated in individuals with periodontitis. Additional research is needed to understand cancer site-specific and racial differences in findings.

Nationally Representative Estimates of Serum Testosterone Concentration in Never-Smoking, Lean Men Without Aging-Associated Comorbidities

Context

Testosterone deficiency prevalence increases with age, comorbidities, and obesity.

Objective

To inform clinical guidelines for testosterone deficiency management and development of targets for nonpharmacologic intervention trials for these men, we determined serum testosterone in never-smoking, lean men without select comorbidities in nationally representative surveys.

Design Setting Participants

We used cross-sectional data for never-smoking, lean men ≥20 years without diabetes, myocardial infarction, congestive heart failure, stroke, or cancer, without use of hormone-influencing medications, and participated in morning sessions of National Health and Nutrition Examination Survey (NHANES) III (phase I 1988-1991) or continuous NHANES (1999-2004). By age, we determined median total testosterone (ng/mL) measured previously by a Food and Drug Administration-approved immunoassay and median estimated free testosterone concentration.

Results

In NHANES III, in never-smoking, lean men without comorbidities, median (25th, 75th percentile) testosterone was 4% to 9% higher than all men-20 to 39 years: 6.24 (5.16, 7.51), 40 to 59: 5.37 (3.83, 6.49), and ≥60: 4.61 (4.01, 5.18). In continuous NHANES, in never-smoking, lean men without comorbidities, levels were 13% to 24% higher than all men-20 to 39 years: 6.26 (5.32, 7.27), 40 to 59: 5.86 (4.91, 6.55), and ≥60: 4.22 (3.74, 5.73). In never-smoking, lean men without comorbidities, median estimated free testosterone was similar to (NHANES III) or slightly higher than (continuous NHANES) in all men.

Conclusions

These nationally representative data document testosterone levels (immunoassay) in never-smoking, lean men without select comorbidities 30 and 15 to 20 years ago. This information can be incorporated into guidelines for testosterone deficiency management and used to develop targets for nonpharmacologic intervention trials for testosterone deficiency.

Serum Urate, Genetic Variation, and Prostate Cancer Risk: Atherosclerosis Risk in Communities (ARIC) Study

BACKGROUND

Evidence is mounting that intraprostatic inflammation influences prostate cancer development. Uric acid crystals depositing in the prostate could result in injury and inflammation, increasing prostate cancer risk.

METHODS

Included were 6,574 men ages 45-64 years who enrolled in the Atherosclerosis Risk in Communities study in 1987 to 1989. We used Cox proportional hazards regression to estimate the association of serum urate concentration alone and to improve accuracy, jointly with a genetic risk score (GRS, N = 4,983) derived from variants predictive of urate concentration, with prostate cancer (N = 813) risk.

RESULTS

Serum urate concentration or joint categories of urate concentration and GRS were not associated with prostate cancer risk (P trend for quartiles = 0.3). Results were generally similar by race and after excluding users of medications that influence uric acid.

CONCLUSIONS

Serum urate alone and with a urate-associated GRS were not associated with prostate cancer risk.

IMPACT

It is unlikely that circulating urate concentration influences prostate cancer development.

Dietary choline and betaine intakes and risk of total and lethal prostate cancer in the Atherosclerosis Risk in Communities (ARIC) Study

PURPOSE

Two prior cohort studies suggested that choline, but not betaine intake, is associated with an increased risk of advanced prostate cancer (PCa). Given that evidence remains limited, we evaluated whether intakes of choline and derivative betaine are associated with total and lethal PCa risk and PCa death in men with PCa.

METHODS

We included 6,528 men (24.4% African American) without a cancer diagnosis at baseline (1987-1989) followed through 2012. Dietary intake was assessed using a food frequency questionnaire coupled with a nutrient database. We used Cox proportional hazards regression to estimate hazards ratios (HRs) and 95% confidence intervals (CIs) of total and lethal PCa risk overall and by race.

RESULTS

Choline intake was not associated with total (n = 811) or lethal (n = 95) PCa risk overall or by race. Betaine intake was inversely associated with lethal (tertile 3 vs 1, HR 0.59, 95% CI 0.35-1.00, p trend = 0.04), but not total PCa risk; patterns for lethal PCa were similar by race. Neither nutrient was associated with PCa death in men with PCa.

CONCLUSIONS

Choline intake was not associated with total or lethal PCa or with PCa death in men with PCa. Betaine intake was inversely associated with lethal, but not total PCa risk or with PCa death in men with PCa. Our results do not support the hypothesis that higher choline intake increases lethal PCa risk, but do suggest that higher betaine intake may be associated with lower lethal PCa risk. Further investigation with a larger number of lethal cases is needed.

Hyperglycemia, Classified with Multiple Biomarkers Simultaneously in Men without Diabetes, and Risk of Fatal Prostate Cancer

The association between hyperglycemia and prostate cancer risk is inconsistent, and its association with prostate cancer mortality is understudied. Thus, we investigated the association between hyperglycemia and prostate cancer risk and mortality using multiple biomarkers simultaneously to classify hyper- and normoglycemia. We conducted a prospective analysis of 5,162 cancer-free men attending visit 2 (1990-1992) of the Atherosclerosis Risk in Communities (ARIC) study followed for total (N = 671) and lethal (N = 69) prostate cancer incidence and prostate cancer mortality (N = 64) through 2012. Men without diagnosed diabetes were classified as normo- or hyperglycemic using joint categories of fasting glucose, glycated hemoglobin, and glycated albumin (or fructosamine) defined by clinical or research cutpoints. We evaluated the multivariable-adjusted association of hyperglycemia with prostate cancer incidence and mortality using Cox proportional hazards regression; men with diagnosed diabetes were included as a separate exposure category. Among 4,753 men without diagnosed diabetes, 61.5% were classified as having hyperglycemia (high on ≥1 biomarker). HbA1c and glycated albumin together classified 61.9% of 1,736 men with normal fasting glucose as normoglycemic. Compared with men who were normal on all three biomarkers, men who were high on ≥1 biomarker had an increased risk of lethal [HR, 2.50; 95% confidence interval (CI), 1.12-5.58] and fatal (HR, 3.20; 95% CI, 1.26-8.48) disease, but not total prostate cancer incidence (HR, 0.98; 95% CI, 0.81-1.20); associations were similar including fructosamine instead of glycated albumin. Our findings indicate hyperglycemia is associated with an increased risk of lethal and fatal prostate cancer, but not total prostate cancer incidence.

Aspirin and Non-Aspirin NSAID Use and Prostate Cancer Incidence, Mortality, and Case Fatality in the Atherosclerosis Risk in Communities Study

BACKGROUND

NSAIDs appear to moderately reduce prostate cancer risk. However, evidence is limited on whether NSAIDs protect against prostate cancer mortality (death from prostate cancer among men without a cancer history) and case fatality (death from prostate cancer among men with prostate cancer), and whether benefits are consistent in white and black men. This study investigated associations of aspirin and non-aspirin (NA) NSAID use with prostate cancer incidence, mortality, and case fatality in a population-based cohort of white and black men.

METHODS

We included 6,594 men (5,060 white and 1,534 black) from the Atherosclerosis Risk in Communities study without a cancer history at enrollment from 1987 to 1989. NSAID use was assessed at four study visits (1987-1998). Cancer outcomes were ascertained through 2012. Cox proportional hazards regression was used to estimate adjusted HRs, overall and by race.

RESULTS

Aspirin use was not associated with prostate cancer incidence. However, aspirin use was inversely associated with prostate cancer mortality [HR, 0.59; 95% confidence interval (CI), 0.36-0.96]. This association was consistent among white and black men and appeared restricted to men using aspirin daily and/or for cardiovascular disease prevention. Aspirin use was inversely associated with case fatality (HR, 0.45; 95% CI, 0.22-0.94). NA-NSAID use was not associated with these endpoints.

CONCLUSIONS

Aspirin use was inversely associated with prostate cancer mortality and case fatality among white and black men.

IMPACT

If confirmed by additional studies, benefits of aspirin for preventing prostate cancer mortality may need to be factored into risk-benefit calculations of men considering an aspirin regimen.

Alternative lengthening of telomeres, ATRX loss and H3-K27M mutations in histologically defined pilocytic astrocytoma with anaplasia

Anaplasia may be identified in a subset of tumors with a presumed pilocytic astrocytoma (PA) component or piloid features, which may be associated with aggressive behavior, but the biologic basis of this change remains unclear. Fifty-seven resections from 36 patients (23 M, 13 F, mean age 32 years, range 3-75) were included. A clinical diagnosis of NF1 was present in 8 (22%). Alternative lengthening of telomeres (ALT) was assessed by telomere-specific FISH and/or CISH. A combination of immunohistochemistry, DNA sequencing and FISH were used to study BRAF, ATRX, CDKN2A/p16, mutant IDH1 p.R132H and H3-K27M proteins. ALT was present in 25 (69%) cases and ATRX loss in 20 (57%), mostly in the expected association of ALT+/ATRX- (20/24, 83%) or ALT-/ATRX+ (11/11, 100%). BRAF duplication was present in 8 (of 26) (31%). H3-K27M was present in 5 of 32 (16%) cases, all with concurrent ATRX loss and ALT. ALT was also present in 9 (of 11) cases in the benign PA precursor, 7 of which also had ATRX loss in both the precursor and the anaplastic tumor. In a single pediatric case, ALT and ATRX loss developed in the anaplastic component only, and in another adult case, ALT was present in the PA-A component only, but ATRX was not tested. Features associated with worse prognosis included subtotal resection, adult vs. pediatric, presence of a PA precursor preceding a diagnosis of anaplasia, necrosis, presence of ALT and ATRX expression loss. ALT and ATRX loss, as well as alterations involving the MAPK pathway, are frequent in PA with anaplasia at the time of development of anaplasia or in their precursors. Additionally, a small subset of PA with anaplasia have H3-K27M mutations. These findings further support the concept that PA with anaplasia is a neoplasm with heterogeneous genetic features and alterations typical of both PA and diffuse gliomas.

Longer-term Lipid-lowering Drug Use and Risk of Incident and Fatal Prostate Cancer in Black and White Men in the ARIC Study

Lipid-lowering medications, particularly statins, may protect against aggressive prostate cancer. Fatal prostate cancer, the most clinically relevant outcome, remains understudied for this association. We prospectively studied lipid-lowering medication use and both incident and fatal prostate cancer in black and white men in the Atherosclerosis Risk in Communities (ARIC) study. A total of 6,518 men without cancer at visit 2 (1990-1992), the start of the statin era, were followed for prostate cancer incidence and death through 2012. Medication use was collected during study visits and telephone calls at up to nine time points during follow-up. Cox regression was used to estimate HR and 95% confidence intervals (CI) of total (white N = 541, black N = 259) and fatal (white N = 56, black N = 34) prostate cancer overall and by race. Lipid-lowering medication use was modeled as time-dependent current use or duration (never, <10, and ≥10 years). By visit 4 (1996-1998), 21% of white and 11% of black men had used a lipid-lowering medication, mostly statins. There was a suggestion that current users were less likely to die from prostate cancer than nonusers (HR = 0.67, 95% CI = 0.42-1.07) after multivariable adjustment. We observed no statistically significant differences between black and white men. Current use was not associated with incident prostate cancer, although long-term use was statistically significantly inversely associated with incidence (HR = 0.68; 95% CI = 0.50-0.92). Long-term lipid-lowering medication use was associated with lower risk of prostate cancer. Current use was possibly associated with fatal prostate cancer.

Association of tumor-infiltrating T-cell density with molecular subtype, racial ancestry and clinical outcomes in prostate cancer

The inflammatory microenvironment plays an important role in the pathogenesis and progression of tumors and may be associated with somatic genomic alterations. We examined the association of tumor-infiltrating T-cell density with clinical-pathologic variables, tumor molecular subtype, and oncologic outcomes in surgically treated primary prostate cancer occurring in patients of European-American or African-American ancestry. We evaluated 312 primary prostate tumors, enriched for patients with African-American ancestry and high grade disease. Tissue microarrays were immunostained for CD3, CD8, and FOXP3 and were previously immunostained for ERG and PTEN using genetically validated protocols. Image analysis for quantification of T-cell density in tissue microarray tumor spots was performed. Automated quantification of T-cell densities in tumor-containing regions of tissue microarray spots and standard histologic sections were correlated (r = 0.73, p < 0.00001) and there was good agreement between visual and automated T-cell density counts on tissue microarray spots (r = 0.93, p < 0.00001). There was a significant correlation between CD3+, CD8+, and FOXP3+ T-cell densities (p < 0.00001), but these were not associated with most clinical or pathologic variables. Increased T-cell density was significantly associated with ERG positivity (median 309 vs. 188 CD3+ T cells/mm2; p = 0.0004) and also with PTEN loss (median 317 vs. 192 CD3+ T cells/mm2; p = 0.001) in the combined cohort of matched European-American and African-American ancestry patients. The same association or a similar trend was present in patients of both ancestries when analyzed separately. When the African-American patients from the matched race set were combined with a separate high grade set of African-American cases, there was a weak association of increased FOXP3+ T-cell densities with increased risk of metastasis in multivariable analysis. Though high T-cell density is associated with specific molecular subclasses of prostate cancer, we did not find an association of T-cell density with racial ancestry.

Abstract 4947: Aspirin use and risk of lethal prostate cancer in the Atherosclerosis Risk in Communities cohort

Background: Aspirin is commonly used to treat pain and inflammation, and is recommended for some individuals for prevention of cardiovascular disease (CVD) and colorectal cancer. Observational studies suggest that aspirin use may also lower risk of prostate cancer. However, there is limited evidence on whether aspirin may protect against lethal prostate cancer in particular, and on whether benefits are consistent in black and white men. This study sought to determine the association between aspirin use and risk of total and lethal prostate cancer, overall and by race, among men in the Atherosclerosis Risk in Communities (ARIC) cohort.

Methods: The ARIC study enrolled individuals from four U.S. communities in 1987-89. This analysis was restricted to white and black men from this cohort who had non-missing data on aspirin use and were cancer-free at baseline. Aspirin use was assessed at four study visits (V1: 1987-89, V2: 1990-92, V3: 1993-95, V4: 1996-98). Indication for aspirin use was reported at V4. Cancer outcomes were ascertained through 2012. Cox proportional hazards regression was used to estimate cause-specific hazard ratios (HRs) and 95% confidence intervals (CIs) for total incident prostate cancer and lethal prostate cancer, defined as cancer that was advanced at diagnosis or fatal during follow-up. Models were adjusted for race, study center, year of birth, education, and family history of prostate cancer (time-fixed), and smoking status, body mass index, use of statins, diabetes, and coronary heart disease (time-varying). Stratified models and likelihood ratio tests were used to test for effect modification by race.

Results: There were 6,594 men (5,060 white, 1,534 black) included in this analysis. Aspirin use was reported by 29%, 33%, 37% and 44% of men at V1, V2, V3, and V4, respectively. Through the end of 2012, 817 total incident prostate cancers, including 97 lethal prostate cancers, were diagnosed. Aspirin use was not associated with risk of total prostate cancer (HR 1.06, 95% CI 0.91-1.23). However, aspirin use was inversely associated with risk of lethal prostate cancer (HR 0.58, 95% CI 0.35-0.95). This association was consistent among both white men (HR 0.64, 95% CI 0.36-1.13) and black men (HR 0.47, 95% CI 0.16-1.35, p-interaction=0.45). When looked at by indication for use, the inverse association with lethal prostate cancer appeared to be only among men who reported using aspirin regularly for CVD prevention (HR 0.63, 95% CI 0.27-1.50).

Conclusions: Aspirin use was inversely associated with lethal prostate cancer, but not total prostate cancer, in this study population. The association was not modified by race and was possibly restricted to men who used aspirin regularly for CVD prevention. Support: NHLBI, NCI, NPCR

Citation Format: Lauren M. Hurwitz, Corinne E. Joshu, John R. Barber, Anna E. Prizment, Mara Z. Vitolins, Miranda R. Jones, Aaron R. Folsom, Misop Han, Elizabeth A. Platz. Aspirin use and risk of lethal prostate cancer in the Atherosclerosis Risk in Communities cohort [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4947.

A unique telomere DNA expansion phenotype in human retinal rod photoreceptors associated with aging and disease

We have identified a discrete, focal telomere DNA expansion phenotype in the photoreceptor cell layer of normal, non-neoplastic human retinas. This phenotype is similar to that observed in a subset of human cancers, including a large fraction of tumors of the central nervous system, which maintain their telomeres via the non-telomerase-mediated alternative lengthening of telomeres (ALT) mechanism. We observed that these large, ultra-bright telomere DNA foci are restricted to the rod photoreceptors and are not observed in other cell types. Additionally, focus-positive rod cells are dispersed homogeneously throughout the posterior retinal photoreceptor cell layer and appear to be human-specific. We examined 108 normal human retinas obtained at autopsy from a wide range of ages. These large, ultra-bright telomere DNA foci were not observed in infants before 6 months of age; however, the prevalence of focus-positive rod cells dramatically increased throughout life. To investigate associations between this phenotype and retinal pathology, we assessed adult glaucoma (N = 29) and diabetic retinopathy (N = 38) cases. Focus-positive rod cells were prominent in these diseases. When compared to the normal group, after adjusting for age, logistic regression modeling revealed significantly increased odds of falling in the high category of focus-positive rod cells for glaucoma and diabetic retinopathy. In summary, we have identified a dramatic telomere alteration associated with aging and diseases affecting the retina.

Enhancing the Infrastructure of the Atherosclerosis Risk in Communities (ARIC) Study for Cancer Epidemiology Research: ARIC Cancer

Background: We describe the expansion of the Atherosclerosis Risk in Communities (ARIC) Study into a cancer cohort. In 1987 to 1989, ARIC recruited 15,792 participants 45 to 64 years old to be sex (55% female), race (27% black), and geographically diverse. ARIC has exceptional data collected during 6 clinical visits and calls every 6 months, repeated biospecimens, and linkage to Medicare claims data.Methods: We established a Cancer Coordinating Center to implement infrastructure activities, convened a Working Group for data use, leveraged ARIC staff and procedures, and developed protocols. We initiated a cancer-specific participant contact, added questions to existing contacts, obtained permission to collect medical records and tissue, abstracted records, linked with state cancer registries, and adjudicated cases and characterizing data.Results: Through 2012, we ascertained and characterized 4,743 incident invasive, first, and subsequent primary cancers among 4,107 participants and 1,660 cancer-related deaths. We generated a total cancer incidence and mortality analytic case file, and analytic case files for bladder, breast, colorectal, liver, lung, pancreas, and prostate cancer incidence, mortality, and case fatality. Adjudication of multiple data sources improved case records and identified cancers not identified via registries. From 2013 onward, we ascertain cases from self-report coupled with medical records. Additional cancer registry linkages are planned.Conclusions: Compared with starting a new cohort, expanding a cardiovascular cohort into ARIC Cancer was an efficient strategy. Our efforts yielded enhanced case files with 25 years of follow-up.Impact: Now that the cancer infrastructure is established, ARIC is contributing its unique features to modern cancer epidemiology research. Cancer Epidemiol Biomarkers Prev; 27(3); 295-305. ©2017 AACR.

A Prospective Study of Chronic Inflammation in Benign Prostate Tissue and Risk of Prostate Cancer: Linked PCPT and SELECT Cohorts

Background: We leveraged two trials to test the hypothesis of an inflammation-prostate cancer link prospectively in men without indication for biopsy.Methods: Prostate Cancer Prevention Trial (PCPT) participants who had an end-of-study biopsy performed per protocol that was negative for cancer and who subsequently enrolled in the Selenium and Vitamin E Cancer Prevention Trial (SELECT) were eligible. We selected all 100 cases and sampled 200 frequency-matched controls and used PCPT end-of-study biopsies as "baseline." Five men with PSA > 4 ng/mL at end-of-study biopsy were excluded. Tissue was located for 92 cases and 193 controls. We visually assessed inflammation in benign tissue. We estimated ORs and 95% confidence intervals (CI) using logistic regression adjusting for age and race.Results: Mean time between biopsy and diagnosis was 5.9 years. In men previously in the PCPT placebo arm, 78.1% of cases (N = 41) and 68.2% of controls (N = 85) had at least one baseline biopsy core (∼5 evaluated per man) with inflammation. The odds of prostate cancer (N = 41 cases) appeared to increase with increasing mean percentage of tissue area with inflammation, a trend that was statistically significant for Gleason sum <4+3 disease (N = 31 cases; vs. 0%, >0-<1.8% OR = 1.70, 1.8-<5.0% OR = 2.39, ≥5% OR = 3.31, P_trend = 0.047). In men previously in the finasteride arm, prevalence of inflammation did not differ between cases (76.5%; N = 51) and controls (75.0%; N = 108).Conclusions: Benign tissue inflammation was positively associated with prostate cancer.Impact: This first prospective study of men without biopsy indication supports the hypothesis that inflammation influences prostate cancer development. Cancer Epidemiol Biomarkers Prev; 26(10); 1549-57. ©2017 AACR.

Abstract 5324: ERG expression and PTEN loss by BMI and weight change in men with prostate cancer

Background: Obesity and weight gain are associated with poor prostate cancer outcome; underlying mechanisms are unknown. Obesity has been more strongly associated with lethal disease in men positive for the TMPRSS2:ERG gene fusion than negative for this fusion. PTEN loss is associated with increased risk of lethal progression; its association with obesity has not been explored. We evaluated whether prevalence of ERG expression and PTEN loss in prostate tumors differs by BMI and weight change.

Methods: From a retrospective cohort study of 1,337 men with clinically-localized prostate cancer who underwent prostatectomy at Johns Hopkins (1993-2006), we sampled 291 men by combination of BMI at 1 year after surgery (normal, overweight, obese) and weight change from 5 years before to 1 year after surgery (loss, maintenance, gain). Within each category, men were frequency-matched on age, Gleason sum, organ confinement, and surgery year. We used genetically validated immunohistochemistry assays to assess ERG positivity and heterogeneous PTEN loss. Logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for the association of BMI and weight change (adjusted for height, starting weight) with ERG positivity and heterogeneous PTEN loss.

Results: Mean age was 56.1 years and mean Gleason sum was 6.2; 73% had organ-confined disease. Prevalence of ERG positivity did not statistically significantly differ by BMI or weight change. However, when jointly categorized by BMI and weight change, overweight/obese men who maintained (OR=2.5; 95%CI 1.1-5.7) or gained weight (OR=2.5; 95%CI 1.1-5.8), and normal weight men who gained weight (OR=4.7; 95%CI 1.4-15.2) were significantly more likely to have ERG positive tumors compared with normal weight men who maintained weight. Overweight/obese men were also significantly more likely (OR=2.4; 95%CI 1.3-4.7) to have PTEN loss compared with normal weight men. When stratified by ERG status, this association appeared to be stronger for men with ERG positive tumors (OR=2.9; 95%CI 1.3-6.8) than for men with ERG negative tumors (OR=1.6; 95%CI 0.6-4.9). Prevalence of PTEN loss did not differ by weight change. When jointly categorized by BMI and weight change, overweight/obese men who maintained (OR=2.0; 95%CI 0.8-5.3) or gained weight (OR=1.9; 95%CI 0.7-5.1) appeared to be more likely to have PTEN loss compared with normal weight men who maintained weight.

Conclusions: Overweight/obese men who maintained or gained weight circa diagnosis and normal weight men who gained weight were more likely to have ERG positive tumors. Overweight/obese men were more likely to have tumors with PTEN loss; this association was stronger among overweight/obese men who also had ERG positive tumors. The TMPRSS2:ERG gene fusion and PTEN loss may contribute to the increased risk of poor prostate cancer outcomes among overweight/obese men. Funding: Prostate Cancer Foundation

Citation Format: Janelle S. Ho, Ibrahim Kulac, Tamara L. Lotan, John R. Barber, Patrick C. Walsh, Misop Han, Angelo M. De Marzo, Elizabeth A. Platz, Corinne E. Joshu. ERG expression and PTEN loss by BMI and weight change in men with prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5324. doi:10.1158/1538-7445.AM2017-5324

Low Intratumoral Mast Cells Are Associated With a Higher Risk of Prostate Cancer Recurrence

BACKGROUND

Mast cells are of interest in prostate cancer because they possess both pro- and anti-tumorigenic properties and are present in the tumor microenvironment. We studied the association of mast cell count and densities with prostate cancer recurrence using tissue microarrays (TMAs) for 462 men who recurred (cases) and 462 controls that were matched to the cases nested in a cohort of radical prostatectomy patients.

METHODS

Dual-immunostaining for mast cell tryptase and epithelial cytokeratin-8 and whole slide image analysis were used to assess total mast cell number, mast cell density (mast cell number/tissue area), and mast cell number per epithelial or stromal area in TMA spots containing tumor (up to 4 per man). We used conditional logistic regression to estimate the odds ratio (OR) and 95% confidence interval of recurrence for the mean, minimum, and maximum mast cell parameters in tumor tissue among each man's TMA spots.

RESULTS

After taking into account matching factors of age, race, Gleason sum, and pathologic stage, higher minimum mast cell density in the tumor (comparing highest to lowest quartiles: OR = 0.58, 95% CI 0.40-0.86; P-trend = 0.004) was associated with a lower risk of recurrence. Patterns for mast cell number and ratio of mast cell number to epithelial or stromal area were similar to those for mast cell density.

CONCLUSIONS

Our results suggest that intratumoral mast cells may be protective against prostate cancer recurrence and could potentially serve as a prognostic biomarker after prostatectomy. Prostate 77: 412-424, 2017. © 2016 Wiley Periodicals, Inc.

Differential long-term stability of microRNAs and RNU6B snRNA in 12-20 year old archived formalin-fixed paraffin-embedded specimens

Background

The quantitative analysis of microRNA (miRNA) gene expression in archived formalin-fixed, paraffin embedded (FFPE) tissues has been instrumental to identifying their potential roles in cancer biology, diagnosis, and prognosis. However, it remains unclear whether miRNAs remain stable in FFPE tissues stored for long periods of time.

Methods

Here we report Taqman real-time RT-PCR quantification of miR-21, miR-141, miR-221, and RNU6B small nuclear RNA (snRNA) levels from 92 radical prostatectomy specimens stored for 12–20 years in FFPE blocks. The relative stability of each transcript over time was assessed using general linear models. The correlation between transcript quantities, sample age, and RNA integrity number (RIN) were determined utilizing Spearman rank correlation.

Results

All transcript levels linearly decreased with sample age, demonstrating a clear loss of miRNA stability and RNU6B snRNA stability over time. The most rapid rates of degradation were observed for RNU6B and miR-21, while miR-141 and miR-221 were more stable. RNA quality was not correlated with sample age or with miR-21, miR-221, or RNU6B snRNA levels. Conversely, miR-141 levels increased with RNA quality.

Conclusions

MiRNA and snRNA levels gradually decreased over an eight year period in FFPE tissue blocks. Sample age was the most consistent feature associated with miRNA stability. The reference snRNA, RUN6B, was more rapidly degraded when compared to miR-141 and miR-221 miRNAs. Various miRNAs demonstrated differential rates of degradation. Quantitative miRNA studies from long-term archived FFPE tissues may therefore benefit from epidemiologic study design or statistical analysis methods that take into account differential storage-dependent transcript degradation.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-016-3008-4) contains supplementary material, which is available to authorized users.

High-resolution telomere fluorescence in situ hybridization reveals intriguing anomalies in germ cell tumors

Testicular germ cell tumor (TGCT) is the most common malignancy of young men. Most patients are completely cured, which distinguishes these from most other malignancies. Orchiectomy specimens (n=76) were evaluated using high-resolution (single-cell discriminative) telomere-specific fluorescence in situ hybridization (FISH) with simultaneous Oct4 immunofluorescence to describe telomere length phenotype in TGCT neoplastic cells. For the first time, the TGCT precursor lesion, germ cell neoplasia in situ (GCNIS) is also evaluated in depth. The intensity of the signals from cancerous cells was compared to the same patient's reference cells-namely, healthy germ cells (defined as "medium" length) and interstitial/somatic cells (defined as "short" telomere length). We observed short telomeres in most GCNIS and pure seminomas (P=.006 and P=.0005, respectively). In contrast, nonseminomas displayed longer telomeres. Lesion-specific telomere lengths were documented in mixed tumor cases. Embryonal carcinoma (EC) demonstrated the longest telomeres. A fraction of EC displays the telomerase-independent alternative lengthening of telomeres (ALT) phenotype (24% of cases). Loss of ATRX or DAXX nuclear expression was strongly associated with ALT; however, nuclear expression of both proteins was retained in half of ALT-positive ECs. The particular distribution of telomere lengths among TGCT and GCNIS precursors implicate telomeres anomalies in pathogenesis. These results may advise management decisions as well.

Inflammation in Benign Prostate Tissue and Prostate Cancer in the Finasteride Arm of the Prostate Cancer Prevention Trial

BACKGROUND

A previous analysis of the placebo arm of the Prostate Cancer Prevention Trial (PCPT) reported 82% overall prevalence of intraprostatic inflammation and identified a link between inflammation and higher-grade prostate cancer and serum PSA. Here, we studied these associations in the PCPT finasteride arm.

METHODS

Prostate cancer cases (N = 197) detected either on a clinically indicated biopsy or on protocol-directed end-of-study biopsy, and frequency-matched controls (N = 248) with no cancer on an end-of-study biopsy were sampled from the finasteride arm. Inflammation in benign prostate tissue was visually assessed using digital images of hematoxylin and eosin-stained sections. Logistic regression was used for statistical analysis.

RESULTS

In the finasteride arm, 91.6% of prostate cancer cases and 92.4% of controls had at least one biopsy core with inflammation in benign areas (P < 0.001 for difference compared with placebo arm). Overall, the odds of prostate cancer did not differ by prevalence [OR, 0.90; 95% confidence interval (CI), 0.44-1.84] or extent (P trend = 0.68) of inflammation. Inflammation was not associated with higher-grade disease (prevalence: OR, 1.07; 95% CI, 0.43-2.69). Furthermore, mean PSA concentration did not differ by the prevalence or extent of inflammation in either cases or controls.

CONCLUSION

The prevalence of intraprostatic inflammation was higher in the finasteride than placebo arm of the PCPT, with no association with higher-grade prostate cancer.

IMPACT

Finasteride may attenuate the association between inflammation and higher-grade prostate cancer. Moreover, the missing link between intraprostatic inflammation and PSA suggests that finasteride may reduce inflammation-associated PSA elevation.

Incremental stiffness and electrical contact conductance in the contact of rough finite bodies

If two half spaces are in contact, there exists a formal mathematical relation between the electrical contact resistance and the incremental elastic compliance. Here, this relation is extended to the contact of finite bodies. In particular, it is shown that the additional resistance due to roughness of the contacting surfaces (the interface resistance) bears a similar relation to the additional compliance as that obtained for the total resistance in the half-space problem.

Determining the contact area in elastic-indentation problems

A general relationship is established, determining the contact area in the indentation of an elastic half-space. Contact pressure is shown to increase monotonically with load throughout the contact area.

Tiger moth responses to a simulated bat attack: timing and duty cycle

Many night-flying insects perform complex, aerobatic escape maneuvers when echolocating bats initiate attack. Tiger moths couple this kinematic defense with an acoustic reply to a bat's biosonar-guided assault. The jamming hypothesis for the function of these moth sounds assumes that tiger moth clicks presented at high densities, temporally locked to the terminal phase of the bat attack will produce the greatest jamming efficacy. Concomitantly, this hypothesis argues that moths warning bats of bad tasting chemicals sequestered in their tissues should call early to give the bat time to process the meaning of the warning signal and that moths calling at low duty cycles are more likely to employ such an aposematic strategy. We report here the first investigation of a tiger moth assemblage's response to playback of a bat echolocation attack sequence. This assemblage of arctiid moths first answered the echolocation attack sequence 960±547 ms (mean ± s.d.) from the end of the bat attack. The assemblage reached a half-maximum response shortly after the first response, at 763±479 ms from the end of the terminal buzz. Tiger moth response reached a maximum at 475±344 ms from the end of the sequence; during the approach phase, well before the onset of the terminal buzz. In short, much of tiger moth response to bat attack occurs outside of the jamming hypotheses' predictions. Furthermore, no relationship exists between the duty cycle of a tiger moth's call (and thus the call's probability of jamming the bat) and its temporal response to bat attack. These data call into doubt the assumptions behind the jamming hypothesis as currently stated but do not directly test the functionality of arctiid sounds in disrupting echolocation in bat-moth aerial battles.

Can two streams of auditory information be processed simultaneously? Evidence from the gleaning bat Antrozous pallidus

A tenet of auditory scene analysis is that we can fully process only one stream of auditory information at a time. We tested this assumption in a gleaning bat, the pallid bat (Antrozous pallidus) because this bat uses echolocation for general orientation, and relies heavily on prey-generated sounds to detect and locate its prey. It may therefore encounter situations in which the echolocation and passive listening streams temporally overlap. Pallid bats were trained to a dual task in which they had to negotiate a wire array, using echolocation, and land on one of 15 speakers emitting a brief noise burst in order to obtain a food reward. They were forced to process both streams within a narrow 300 to 500 ms time window by having the noise burst triggered by the bats' initial echolocation pulses as it approached the wire array. Relative to single task controls, echolocation and passive sound localization performance was slightly, but significantly, degraded. The bats also increased echolocation interpulse intervals during the dual task, as though attempting to reduce temporal overlap between the signals. These results suggest that the bats, like humans, have difficulty in processing more than one stream of information at a time.