The Interplay Effect and Mitigations with Cyclotron and Linac Proton Beam Scanning for Lung SBRT

PURPOSE/OBJECTIVE(S)

To evaluate the impact of different types of pencil beam scanning proton accelerators and spot sizes on interplay effects, mitigations, and plan quality for lung cancer patients treated with SBRT.

MATERIALS/METHODS

Twenty lung cancer patients (ten peripheral and ten central tumors) treated in our institution with photon SBRT were selected to represent varying tumor volumes and respiratory motion amplitudes for this retrospective study. The respiratory motion amplitude ranged from 0.1 to 1.0 cm with compression. For each patient, plans were created using: 1) cyclotron-generated proton beams (CPB) (σ: 2.7-7.0 mm); 2) linear accelerator proton beams (LPB) (σ: 2.9-5.5 mm); and 3) linear accelerator proton minibeams (LPMB) (σ: 0.9-3.9 mm). Plans were robustly optimized on the GTV using each individual 4DCT phase. Single-filed optimization (SFO) plans were the first attempt, and if the plan quality did not meet the dosimetric requirement, multi-field optimization (MFO) was used. MFO plans were created for all patients for comparison. For each patient, all plans were normalized to have the same dose to 99% of the GTV. Interplay effects were evaluated for ten scenarios of treatment delivery starting in ten breathing phases using machine generic time models and a constant breathing period of 4 seconds. Volumetric repainting (VR) was performed 2-6 times for each plan. To assess plan quality in the nominal scenario, we compared the conformity index (CI), R50, and the percentage of lung volume receiving 20 Gy (RBE) (V20Gy). CI is defined as the ratio of the 100% isodose volume to the GTV. R50 is defined as the 50% isodose volume divided by the GTV. Dmax and V18Gy of the proximal bronchial tree (PBT) were evaluated for central tumors.

RESULTS

Twelve of 20 plans can be optimized sufficiently with SFO. In interplay effect evaluation, the mean V100%RX values of the GTV were 99.42±0.6%, 97.52±3.9%, and 94.49±7.3%for CPB, LPB, and LPMB plans respectively. After VR 2/3/5 times, the V100%RX values were improved (on average) by 0.13%/1.84%/4.63% for CPB/LPB/LPMB plans. The delivery time for VR plans was the lowest for LPB plans, while delivery time for LPMB was on average 1 minute longer than CPB plans. VR showed no effect on lung V20Gy, Dmax and V18Gy of the PBT. SFO plans were more robust against the interplay effect compared with MFO plans for LPB and LPMB. Average CIs of 1.88±0.4, 1.79±0.4, and 1.75±0.4; average R50s of 7.99±4.0, 6.68±3.0, and 5.70±2.6; and average lung V20Gy values of 2.81±1.5, 2.26±1.3, and 1.85±1.1 were obtained for CPB, LPB, and LPMB plans, respectively. Dmax and V18Gy of the PBT decreased with decreasing spot sizes.

CONCLUSION

LPMB, with the smallest spot size, produced superior plan quality. In the absence of VR, proton machines with large spot sizes generated more robust plans against interplay effects. VR improved the plan robustness against interplay effects for modalities with small spot sizes and fast energy changes, preserving the low dose sparing aspect of the LPMB, even when motion is included.

Investigation of the Relationship between Aperture Use for Treating Small and Shallow Brain Lesions in Proton Therapy with Different Spot Size Variations in Three Proton Therapy Systems

PURPOSE/OBJECTIVE(S)

To compare plan quality among standard vs. aperture-based Intensity-Modulated Proton Therapy (IMPT) using cyclotron-generated proton beams (CPB), linear accelerator proton beams (LPB), and linear accelerator proton minibeams (LPMB) for multiple brain metastases.

MATERIALS/METHODS

Fifty-five brain lesions from twenty patients were planned with three different spot size ranges using CPBs (σ: 2.7-7.0 mm) and compared against LPBs (σ: 2.9-5.5 mm), and LPMBs (σ: 0.9-3.9 mm). Apertures with a diameter of 0.3 cm were applied to beams irradiating all tumors < 1 cm3 in volume and any tumor < 2.5 cm depth in the patient and compared against the same patient plans containing no apertures. All plans were optimized with the multi-field optimization (MFO) technique using the Monte Carlo algorithm. Dose coverage to each lesion for each proton plan was set to 99% of the GTV receiving the prescription (Rx) dose for all plans. Robustness with ±2 mm setup uncertainty and ±2% range uncertainty was included in robust evaluation using V100%Rx > 95% of the GTV. Conformity index (CI) and gradient index (GI) were used to analyze the effect of apertures vs. no apertures (standard) for each IMPT plan type. CI was defined as the volume of the 100% isodose line divided by the volume of the GTV + 2 mm expansion to account for robust planning. The Wilcoxon signed rank test was utilized to determine the statistical significance of dosimetric results compared between aperture-based and standard IMPT plans.

RESULTS

When apertures were implemented in the treatment planning for all shallow and small brain lesions, shallow brain tumors showed the most prominent improvement in conformity and gradient index. A 6.7% difference in average conformity was calculated for standard vs. aperture-based plans for LPMBs, followed by a 5.3% improvement for CPBs. Improvement in gradient index for standard vs. aperture-based plans was significant for both shallow and deeper tumors for CPB and LPB plan types, as shown in Table 1 below. CPB and LPB plan gradient indices were statistically significant for comparing aperture-based vs. standard IMPT plans.

CONCLUSION

We successfully quantified plan quality and evaluated results for aperture- vs. standard IMPT plans using CPBs, LPBs, and LPMBs for brain metastases. Plan quality improves the greatest with apertures applied to beams irradiating shallow tumors. Apertures may not be necessary for small, deeper tumors with IMPT.

Dosimetric Risk Estimation of Chest Wall Pain Following 5-Fraction Lung Stereotactic Body Radiotherapy

PURPOSE/OBJECTIVE(S)

Development of chest wall pain (CWP) following lung stereotactic body radiotherapy (SBRT) is a known toxicity, particularly for peripheral lesions. While CW V30 has been most consistently associated with development of post-SBRT CWP, existing series included heterogeneous dose-fractionation regimens, most commonly 48-54 Gy in 3-4 fractions. The present study aims to identify clinical and dosimetric variables associated with development of CWP among patients treated with 5 fraction lung SBRT.

MATERIALS/METHODS

Intradepartmental quality assurance database of SBRT patients was queried to identify lung targets treated to a minimum of 45 Gy in 5 fractions. Retrospective chart and plan reviews were performed on these cases to collect patient, tumor, and treatment-related data, selecting for patients with peripheral lesions (any histology), and recording presence or absence of CWP during or following SBRT. Patients with less than 6 months of post-SBRT clinical follow-up were excluded. The CW was defined as a 2 cm expansion of the ipsilateral lung (inclusive of intercostal musculature, ribs, and superficial soft tissue). Logistic regression analyses were performed on continuous and nominal data to determine statistically significant (p<0.05) correlations between clinical (age, gender, known osteopenia/osteoporosis, diabetes, prior thoracic radiotherapy, lesion distance to CW), treatment (interval of SBRT delivery, dose prescribed), and dosimetric (Dose to 0.1/1/5/10cc; V30, V40) factors with CWP.

RESULTS

Between February 2011 and January 2022, 93 patients were identified for inclusion in the present analysis, treated to 100 total lesions in 99 courses of treatment. Median patient age was 75 years (range 34-90), 48 (52%) were female, and 29 (of 99 treatment courses; 29%) had received prior thoracic radiotherapy. Median SBRT dose was 50 Gy (45-60), delivered over a median of 9 days (4-18). At a median post-SBRT follow-up of 21 months, 11 patients developed CWP at a median of 9 months post-SBRT (0-32). Statistically significant correlations were identified between CWP and known pre-existing osteopenia or osteoporosis, target distance to CW, and CW D0.1cc, D1cc, D5cc, and D10cc, but not CW V30 or V40. Crude risk of CWP for selected clinically practical dose-volume thresholds are presented in Table 1: CONCLUSION: For patients treated with lung SBRT in 5 fractions, dose to CW volume thresholds appears to correlate more closely than V30 or V40 for CWP estimation. Further investigation and validation of optimal CW volume thresholds, as well as integration of pre-existing condition clinical factors in risk estimation, appears warranted.

Prevalence and Correlates of Cardiovascular, Pulmonary, Cancer, and Mental Health Comorbidities Among Adults With HIV Who Smoke

ABSTRACT

Using data from the D.C. Cohort Longitudinal HIV Study, we examined (a) diagnosed mental health and (b) cardiovascular, pulmonary, or cancer (CPC) comorbidity among adults with HIV who smoked. Among 8,581 adults, 4,273 (50%) smoked; 49% of smokers had mental health, and 13% of smokers had a CPC comorbidity. Among smokers, non-Hispanic Black participants had a lower risk for mental health (prevalence ratio [PR]: 0.69; 95% confidence interval [CI] [0.62-0.76]) but a higher risk for CPC (PR: 1.17; 95% CI [0.84-1.62]) comorbidity. Male participants had a lower risk for mental health (PR: 0.88; 95% CI [0.81-0.94]) and CPC (PR: 0.68; 95% CI [0.57-0.81]) comorbidity. All metrics of socioeconomic status were associated with a mental health comorbidity, but only housing status was associated with a CPC comorbidity. We did not find any association with substance use. Gender, socioeconomic factors, and race/ethnicity should inform clinical care and the development of smoking cessation strategies for this population.

Social media engagement, perceptions of social media costs and benefits, and well-being in college student-athletes

Objective: The present study investigated the association between social media engagement and factors related to well-being (e.g., depression, anxiety, sleep, loneliness, self-esteem). Participants: A sample of 1120 college student-athletes (338 males, 777 females, 5 identified as non-binary) from nine universities participated in this study. Method: Data were collected through self-report measures and screen shots of participants' screen time in the previous week. Results: Overall screen time taken from devices was not associated with self-reported well-being, whereas use of social media during daily activities was related to worse well-being across domains (e.g., lower self-esteem, higher fear of missing out, stress, anxiety, depression). In addition, student-athlete perceptions that social media interfere with their lives were related to worse well-being. Conclusions: The implications of these findings, including the possibility of using protective behavioral strategies (PBS) to reduce negative impacts of social media in college students, are discussed.

Smoking cessation intentions and attempts one year after the federally mandated smoke-free housing rule

The present study examines public housing residents' smoking cessation intentions, expectancies, and attempts one year after implementation of the Department of Housing and Urban Development's mandatory smoke-free rule in public housing. The sample includes 233 cigarette smokers, ages 18-80, who reside in the District of Columbia Housing Authority. Data collection occurred between March and August 2019. Descriptive statistics, chi-square, and Wilcoxon two-sample test analyses assessed smoking cessation intentions, expectancies, and attempts across resident demographics and characteristics. Findings showed 17.2% of residents reported not thinking about quitting, 39.1% reported thinking about quitting, and 48.6% reported thinking about quitting specifically because of the rule. Residents ages 60-80 were more likely to consider quitting because of the rule, compared to residents ages 18-59. Of those thinking of quitting, 58.6% were sure they could quit if they tried. Those thinking of quitting due to the rule (62.0%) were more likely to have made at least one quit attempt in the past 3 months than those i not attributinging thinking of quitting to the rule. Res Residents trying to quit reported an average of 2.7 attempts in the last 3 months;; most perceived evidence-based cessation supports as not helpful. A A majority reported thinking about quitting and attempting to quit but continuing to smoke, indicating a significant gap between intent to quit and successfully quitting. Results suggest that the rule positively influenced smoking behaviors. However, additional interventions are needed to assist public housing residents with successfully quitting smoking.

Implementation of the Department of Housing and Urban Development's Smoke-Free Rule: A Socio-Ecological Qualitative Assessment of Administrator and Resident Perceptions

In July 2018, the United States Department of Housing and Urban Development (HUD) implemented a mandatory smoke-free rule in public housing. This study assessed administrator and resident perceptions of rule implementation during its initial year in the District of Columbia Housing Authority (DCHA). Assessment included nine focus groups (n = 69) with residents and in-depth interviews with administrators (n = 7) and residents (n = 26) from 14 DCHA communities (family = 7 and senior/disabled = 7). Semi-structured discussion guides based on the multi-level socio-ecological framework captured dialogue that was recorded, transcribed verbatim, and coded inductively. Emerging major themes for each socio-ecological framework level included: (1) Individual: the rule was supported due to perceived health benefits, with stronger support among non-smokers; (2) Interpersonal: limiting secondhand smoke exposure was perceived as a positive for vulnerable residents; (3) Organizational: communication, signage, and cessation support was perceived as a need; (4) Community: residents perceived mobility, disability, weather, and safety-related issues as barriers; and (5) Public Policy: lease amendments were perceived as enablers of rule implementation but expressed confusion about violations and enforcement. A majority of administrators and residents reported favorable implications of the mandated HUD rule. The novel application of a socio-ecological framework, however, detected implementation nuances that required improvements on multiple levels, including more signage, cessation support, clarification of enforcement roles, and addressing safety concerns.

A pilot randomized controlled trial of a tailored smoking cessation program for people living with HIV in the Washington, D.C. metropolitan area

OBJECTIVE

Morbidity and mortality from smoking-related diseases among people living with HIV (PLWH) in the U.S. surpasses that due to HIV itself. Conventional smoking cessation treatments have not demonstrated strong efficacy among PLWH. We conducted a pilot randomized controlled trial (RCT) to evaluate a tailored smoking cessation intervention based on the minority stress model. We compared standard of care counseling (SOC) to a tailored intervention (TI) including one face-to-face counseling session incorporating cognitive behavioral therapy to build resilience, and 30 days of 2-way text messaging.

RESULTS

The primary outcome was smoking cessation. Secondary outcomes included cigarettes per day (CPD), exhaled carbon monoxide (CO), and cessation self-efficacy. A total of 25 participants were enrolled (TI:11, SOC:14), and 2 were lost to follow-up. There were no significant differences in quit rates between study groups. However, there was a significantly greater decrease in CPD in the TI versus SOC (13.5 vs. 0.0, p-value:0.036). Additionally, self-efficacy increased in both groups (TI p-value:0.012, SOC p-value:0.049) and CO decreased in both groups (TI p-value: < 0.001, SOC p-value:0.049). This intervention shows promise to support smoking cessation among PLWH. A larger study is needed to fully evaluate the efficacy of this approach.

CLINICAL TRIAL

Trial Registration: Retrospectively registered (10/20/2020) NCT04594109.

Harm Perceptions of Menthol and Nonmenthol Cigarettes Differ by Brand, Race/Ethnicity, and Gender in US Adult Smokers: Results from PATH Wave 1

INTRODUCTION

Harm perceptions of menthol cigarettes may contribute to their appeal and use. African-Americans, women, and younger smokers disproportionately use menthol cigarettes, and may misperceive harm of menthol cigarettes.

METHODS

Data were from Wave 1 of the Population Assessment of Tobacco and Health (PATH) Study. Weighted analyses of current adult smokers (18 and older) were used to estimate the correlates of menthol smoking among all cigarette brands and separately for the top three cigarette brands (Newport, Camel, and Marlboro). Adjusted models examined the main effect of menthol smoking on harm perceptions of one's own brand of cigarette and interactions with race/ethnicity, age, and gender.

RESULTS

Menthol cigarettes were used by nearly 40% of current smokers, although the prevalence of menthol smoking differed across the top three brands (94% Newport, 46% Camel, and 18% Marlboro). Among menthol smokers, 80% perceived their cigarette as equally harmful, 14% perceived their brand as more harmful, and 7% perceived their brand as less harmful. In adjusted models, menthol smokers were more likely than nonmenthol smokers to misperceive their own brand as more harmful than other brands (compared to no difference in harm). Race and gender emerged as moderators of the association between menthol brand preference and harm perceptions.

CONCLUSIONS

In adjusted analyses, menthol smokers were more likely than nonmenthol smokers to perceive their brand as more harmful than other brands, with differences by sub-groups who disproportionately use menthol.

IMPLICATIONS

Menthol cigarettes have been historically marketed with messages conveying lower harm than other cigarettes. Little is known about how contemporary adult menthol smokers perceive the harm of their usual brand, and potential differences by race, gender, and young adult versus older adult age group. After adjusting for other factors, menthol smokers were more likely than nonmenthol smokers to perceive their cigarette brand as more harmful than other brands. Further, the association between menthol smoking and harm perceptions differed by race and gender, but not by age group (young adult vs. older adult). This type of large-scale study identifies critical links between menthol smoking and harm perceptions among vulnerable smokers that will inform regulatory actions designed to decrease smoking-related harm.

742. “Troponin Leaks” in Patients with Acute Respiratory Viral Infections Enrolled in SUPERNOVA: A Marker of Worse Clinical Outcomes

Background

Cardiac troponin I (cTnI) is a specific marker of cardiac muscular injury. Many patients hospitalized with acute respiratory illness (ARI) have elevated cTnI levels but do not meet EKG criteria for an acute ischemic cardiac event. Troponin leaks could be due to demand ischemia or acute inflammation of the myocardium. We hypothesized that patients with viral ARI and elevated cTnI have worse cardiopulmonary outcomes than those with viral ARI and normal cTnI.

Methods

From November 11, 2016–September 30, 2017 nasopharyngeal swabs from patients enrolled in SUPERNOVA ARI Study, a CDC/2-VA site, active surveillance platform to evaluate the incidence of viral infection in patients hospitalized with symptoms and/or signs of ARI, were tested using a FilmArray Respiratory Panel. Based on detection of any virus, patients were categorized as positive (vPCR+) or negative (vPCR−). Patient enrolled at the Houston site with cTnI obtained <48 hours of admission were included in the analysis. cTnI above upper limit of normal (>0.03 ng/dL) was defined as elevated. Demographic and clinical data were abstracted from chart review. Outcomes were myocardial infarction (MI) on admission, 30- and 90-day re-admissions due to cardio-respiratory illness and 30- and 90-day all-cause mortality. For the univariable analysis of baseline factors and outcomes we used unpaired t-tests for continuous variables and χ² or Fisher exact test for categorical variables as appropriate.

Results

Ninety-four of 332 cases were vPCR positive and cTnI levels on admission were available in 86. Demographics and comorbidities were all similar for the high (N = 42) and normal (N = 44) cTnI groups. Compared with normal cTnI group, those with high cTnI had similar 30- and 90-day readmission rates (14% vs. 9%, P = 0.4 and 26% vs. 16%, respectively, P = 0.2). However, 30- and 90-day mortality rates were higher for high cTnI patients (10% vs. 0% and 19% vs. 5%, P < 0.03).

Conclusion

Troponin elevation on patients with a documented viral respiratory infection is associated with higher 30- and 90-day mortality rates. Troponin leaks should not be dismissed as a trivial finding in this group of patients. Further work on its pathogenesis is warranted.

Disclosures

All authors: No reported disclosures.

The IAEA Human Health Campus: Online Educational Resource for Health Care Professionals in Radiation Medicine

Background: Cognizant of the educational needs of the member states, and taking advantage of the current technological advances in this digital age, the International Atomic Energy Agency (IAEA) officially launched in 2010 the Human Health Campus (HHC; http://humanhealth.iaea.org ), which is an online educational resource initiative geared toward enhancing professional knowledge of health professionals in radiation medicine. Aim: Determine how and by whom the IAEA HHC is being visited and used since its inception in October 2010. Methods: Using the information provided by Google Analytics, determine the overall key performance indicators (KPIs) such as total sessions, total users, total page views, session duration, including daily number of visits to the HHC, county of origin, evaluation of the most popular sections and source of the traffic. Results: Since its launch on October 6th, 2010, KPIs are as follows: total sessions 374,279, total users 243,195, total page views 1,393,310, pages/session 3.72, average session duration 00:03:08. % of new sessions 64.92%. The HHC has witnessed continual growth year on year (YoY) in total sessions (visits) since its inception in October 2010, and total users. For 2016 (the highest performing year so far) there were 201 visits/day, 40% increase in traffic YoY and 20% user growth. Traffic to the Webinar content has seen sustained growth in the number of YoY since being introduced to the HHC in 2013. 2016 saw the largest increase of over +600%. E-Learning modules have also seen growth in the traffic YoY since being introduced to the HHC in 2011. The year 2015 saw a large increase in total traffic with over +95%. E-Learning traffic accounts for almost 25% of all traffic to the Nuclear Medicine section. Visits by mobile devices have increased YoY exponentially since the launch of the HHC, with the mobile traffic growing strong through 2015-2016 with an increase of 5482 sessions, or an 81% uplift YoY. For 2017, it represented 18% of the total traffic (from 3% in 2012). There is a clear prevalence of desktop users (85.5%), as the preferred method of browsing the HHC. A total of 210 countries and overseas territories have visited the HHC. The United States is the largest contributor of traffic from a global perspective with 16.31% of total traffic, almost double the next largest which is the UK with 9.10%. India with 5.45% and Australia with 3.27% of total traffic, respectively, round out the top 4. Not surprisingly, more than 60% of users are from English-speaking countries. Spanish is the second most popular language of users with just over 6% of total traffic. Conclusion: The HHC is an IAEA open access Web based educational resource for professionals in the field of radiation medicine being visited by as many as 210 countries. The upward trend in its use suggests that the IAEA HHC will continue to be an important player in providing educational resources for professionals worldwide.

Dynamics of virus-specific T cell immunity in pediatric liver transplant recipients

Immunosuppression following solid organ transplantation (SOT) has a deleterious effect on cellular immunity leading to frequent and prolonged viral infections. To better understand the relationship between posttransplant immunosuppression and circulating virus-specific T cells, we prospectively monitored the frequency and function of T cells directed to a range of latent (CMV, EBV, HHV6, BK) and lytic (AdV) viruses in 16 children undergoing liver transplantation for up to 1 year posttransplant. Following transplant, there was an immediate decline in circulating virus-specific T cells, which recovered posttransplant, coincident with the introduction and subsequent routine tapering of immunosuppression. Furthermore, 12 of 14 infections/reactivations that occurred posttransplant were successfully controlled with immunosuppression reduction (and/or antiviral use) and in all cases we detected a temporal increase in the circulating frequency of virus-specific T cells directed against the infecting virus, which was absent in 2 cases where infections remained uncontrolled by the end of follow-up. Our study illustrates the dynamic changes in virus-specific T cells that occur in children following liver transplantation, driven both by active viral replication and modulation of immunosuppression.

A Type 1 Diabetes Genetic Risk Score Predicts Progression of Islet Autoimmunity and Development of Type 1 Diabetes in Individuals at Risk

OBJECTIVE

We tested the ability of a type 1 diabetes (T1D) genetic risk score (GRS) to predict progression of islet autoimmunity and T1D in at-risk individuals.

RESEARCH DESIGN AND METHODS

We studied the 1,244 TrialNet Pathway to Prevention study participants (T1D patients' relatives without diabetes and with one or more positive autoantibodies) who were genotyped with Illumina ImmunoChip (median [range] age at initial autoantibody determination 11.1 years [1.2-51.8], 48% male, 80.5% non-Hispanic white, median follow-up 5.4 years). Of 291 participants with a single positive autoantibody at screening, 157 converted to multiple autoantibody positivity and 55 developed diabetes. Of 953 participants with multiple positive autoantibodies at screening, 419 developed diabetes. We calculated the T1D GRS from 30 T1D-associated single nucleotide polymorphisms. We used multivariable Cox regression models, time-dependent receiver operating characteristic curves, and area under the curve (AUC) measures to evaluate prognostic utility of T1D GRS, age, sex, Diabetes Prevention Trial-Type 1 (DPT-1) Risk Score, positive autoantibody number or type, HLA DR3/DR4-DQ8 status, and race/ethnicity. We used recursive partitioning analyses to identify cut points in continuous variables.

RESULTS

Higher T1D GRS significantly increased the rate of progression to T1D adjusting for DPT-1 Risk Score, age, number of positive autoantibodies, sex, and ethnicity (hazard ratio [HR] 1.29 for a 0.05 increase, 95% CI 1.06-1.6; P = 0.011). Progression to T1D was best predicted by a combined model with GRS, number of positive autoantibodies, DPT-1 Risk Score, and age (7-year time-integrated AUC = 0.79, 5-year AUC = 0.73). Higher GRS was significantly associated with increased progression rate from single to multiple positive autoantibodies after adjusting for age, autoantibody type, ethnicity, and sex (HR 2.27 for GRS >0.295, 95% CI 1.47-3.51; P = 0.0002).

CONCLUSIONS

The T1D GRS independently predicts progression to T1D and improves prediction along T1D stages in autoantibody-positive relatives.

School-level disadvantage and failed cessation treatment among adolescent smokers

INTRODUCTION

While understanding factors that lead to successful adolescent smoking cessation outcomes is necessary, it is also prudent to determine factors and conditions that contribute to failure to quit smoking. The present study posits that adolescents' proximal environments, such as schools, may influence cessation treatment outcomes.

METHODS

Using aggregated and geographically-referenced data from multi-year school-based cessation trials with 14-19 year olds seeking cessation in 5 States of the USA, the present study developed and applied a tobacco-specific socio-spatial model inclusive of Hierarchical Linear Modeling. Specifically, this novel approach spatially joined individual data files (n=8855) with measures of school (n=807) and county socio-economic factors. Once linked multi-level analyses explored the extent to which cessation treatment failure was explained by the interplay of individual, school and county-level factors. Treatment was deemed as failing to meet its primary goals if participants continued to smoke cigarettes, measured 3-months post baseline.

RESULTS

Ten per cent of the variation in cessation treatment failure was attributable to school-level variables. Adolescent smokers were more likely to experience failure to quit in: a) school districts with large percentages of the population having less than high-school education, and b) schools with a higher ratio of students to teachers. The strength of the relationship between cessation self-efficacy and treatment success was further weakened among adolescents attending schools with higher percentages of students eligible for free or reduced lunch programs.

CONCLUSIONS

Findings implicate school-level socio-economic disadvantage as a significant factor inhibiting cessation, regardless of adolescent self-efficacy to quit smoking. Understanding the interplay of proximal school environments and individual-level factors may provide insights to educators, policy makers and practitioners into the complexities that inhibit or strengthen an adolescent's smoking cessation treatment experience.

Variation in heterostylous breeding systems in neighbouring populations of Oxalis alpina (Oxalidaceae)

The heterostylous reproductive system of Oxalis alpina in the Galiuro Mts. of Arizona was investigated using field surveys, controlled crosses in the greenhouse and measurements of reproductive morphs. Although populations in the Pinaleño Mts. to the immediate east and in the Santa Catalina Mts. to the immediate west have derived distylous reproductive systems, tristyly, the ancestral reproductive system in O. alpina, has been retained in the Galiuro Mts.

POPULATION

Tristylous incompatibility relationships in the Galiuro population are modified from the ancestral condition, with significant loss of incompatibility differentiation between stamen whorls of both short- and long-styled morphs. Morphological adjustments of anther positions in the Galiuro population of O. alpina match those expected in light of incompatibility modification, with divergence of the mid-level anthers away from the position of the mid stigmas of the mid-styled morph. The occurrence of tristyly in an area of Arizona where distyly is found in adjacent mountain ranges is particularly remarkable, and indicates both the isolation of populations restricted to the upper elevations of these mountain ranges and variation in the tempo of evolution over short geographic distances.

Fishpathogens.eu/noda: a free and handy online platform for Betanodavirus targeted research and data sharing

Viral nervous necrosis (VNN) is a severe neuropathological disease affecting a broad variety of finfish species worldwide. The causative agents of VNN are small viruses with a bi-segmented RNA genome known as betanodaviruses. At least four species with distinct but yet insufficiently characterized epidemiological features are recognized. The spread of VNN to an increasing number of host species, its wide geographic extent and its economical and ecological impacts justify the importance of collating as much molecular data as possible for tracing the origin of viral isolates and highlight the need for a freely accessible tool for epidemiological and molecular data sharing and consultation. For this purpose, we established a web-based specific database using the www.fishpathogens.eu platform, with the aim of collecting molecular and epidemiological information on VNN viruses, with relevance to their control, management and research studies.

Evaluation of Flexural, Diametral Tensile, and Shear Bond Strength of Composite Repairs

Objective

Repairing composite restorations may be a more conservative treatment than replacing the entire restoration. The objective of this in vitro study was to determine the best repair method by measuring flexural, diametral tensile, and shear bond strength of repaired composites in which the surfaces were treated with chemical primers (Add & Bond or Silane Bond Enhancer), a bonding agent (Optibond Solo Plus [OBSP]), or mechanical retention with a bonding agent.

Methods

Filtek Supreme Ultra shade B1B was placed in special molds to fabricate specimens that served to test the flexural, diametral tensile, or shear strength of the inherent resin substrate. The same molds were modified to make specimens for testing repair strength of the resin. Repairs were made immediately or after aging in deionized water at 37°C for seven days. All repair sites were finished with coarse Sof-Lex discs to simulate finishing new restorations or partially removing aged restorations. Repair surfaces were treated with one of the following: 1) phosphoric-acid etching and OBSP; 2) Add & Bond; 3) phosphoric-acid etching, Silane Bond Enhancer, and OBSP; or 4) quarter round bur, phosphoric-acid etching, and OBSP. Specimens were placed back in the original molds to fabricate specimens for diametral tensile or flexural testing or in an Ultradent jig to make specimens for shear bond testing. Composite resin in shade B5B was polymerized against the treated surfaces to make repairs. Two negative control groups for the three testing methods consisted of specimens in which repairs were made immediately or after aging without any surface treatments. Controls and experimental repairs were aged (water 37°C, 24 hours) before flexural, diametral tensile, or shear testing in an Instron Universal testing machine at a crosshead speed of 0.5 mm/min.

Results

Experimental flexural repair strengths ranged from 26.4% to 88.6% of the inherent substrate strength. Diametral tensile repair strengths ranged from 40% to 80% of the inherent substrate strength, and shear bond strength repairs ranged from 56% to 102%. Geometric means were statistically analyzed with two-way analysis of variance on their log-transformed values. Significant differences were determined using Tukey honestly significant difference (p&lt;0.05).

Conclusions

Depending on the mechanical property being tested, surface treatments produced different results. OBSP produced more consistent results than chemical primers.

Pegylated interferons Lambda-1a and alfa-2a display different gene induction and cytokine and chemokine release profiles in whole blood, human hepatocytes and peripheral blood mononuclear cells

Pegylated interferon-lambda-1a (Lambda), a type III interferon (IFN) in clinical development for the treatment of chronic HCV infection, has shown comparable efficacy and an improved safety profile to a regimen based on pegylated IFN alfa-2a (alfa). To establish a mechanistic context for this improved profile, we investigated the ex vivo effects of Lambda and alfa on cytokine and chemokine release, and on expression of IFN-stimulated genes (ISGs) in primary human hepatocytes and peripheral blood mononuclear cells (PBMCs) from healthy subjects. Our findings were further compared with changes observed in blood analysed from HCV-infected patients treated with Lambda or alfa in clinical studies. mRNA transcript and protein expression of the IFN-λ-limiting receptor subunit was lower compared with IFN-α receptor subunits in all cell types. Upon stimulation, alfa and Lambda induced ISG expression in hepatocytes and PBMCs, although in PBMCs Lambda-induced ISG expression was modest. Furthermore, alfa and Lambda induced release of cytokines and chemokines from hepatocytes and PBMCs, although differences in their kinetics of induction were observed. In HCV-infected patients, alfa treatment induced ISG expression in whole blood after single and repeat dosing. Lambda treatment induced modest ISG expression after single dosing and showed no induction after repeat dosing. Alfa and Lambda treatment increased IP-10, iTAC, IL-6, MCP-1 and MIP-1β levels in serum, with alfa inducing higher levels of all mediators compared with Lambda. Overall, ex vivo and in vivo induction profiles reported in this analysis strongly correlate with clinical observations of fewer related adverse events for Lambda vs those typically associated with alfa.

Organo-selenium-containing dental sealant inhibits bacterial biofilm

Oral bacteria, including Streptococcus mutans and Streptococcus salivarius, contribute to tooth decay and plaque formation; therefore, it is essential to develop strategies to prevent dental caries and plaque formation. We recently showed that organo-selenium compounds covalently attached to different biomaterials inhibited bacterial biofilms. Our current study investigates the efficacy of an organo-selenium dental sealant (SeLECT-Defense(TM) sealant) in inhibiting S. mutans and S. salivarius biofilm formation in vitro. The organo-selenium was synthesized and covalently attached to dental sealant material via standard polymer chemistry. By colony-forming unit (CFU) assay and confocal microscopy, SeLECT-Defense(TM) sealant was found to completely inhibit the development of S. mutans and S. salivarius biofilms. To assess the durability of the anti-biofilm effect, we soaked the SeLECT-Defense(TM) sealant in PBS for 2 mos at 37°C and found that the biofilm-inhibitory effect was not diminished after soaking. To determine if organo-selenium inhibits bacterial growth under the sealant, we placed SeLECT-Defense sealant over a lawn of S. mutans. In contrast to a control sealant, SeLECT-Defense(TM) sealant completely inhibited the growth of S. mutans. These results suggest that the inhibitory effect of SeLECT-Defense(TM) sealant against S. mutans and S. salivarius biofilms is very effective and durable.

Observation of a relaxed plasma state in a quasi-infinite cylinder

A helical relaxed plasma state is observed in a long cylindrical volume. The cylinder is long enough so that the predicted minimum energy state is a close approximation to the infinite cylinder solution. The plasma is injected at v ≥ 50 km/s by a coaxial magnetized plasma gun located at one end of the cylindrical volume. The relaxed state is rapidly attained in 1-2 axial Alfvén times after initiation of the plasma. Magnetic data are favorably compared with an analytical model. Magnetic data exhibit broadband fluctuations of the measured axial modes during the formation period. The broadband activity rapidly decays as the energy condenses into the lowest energy mode, which is in agreement with the minimum energy eigenstate of [Symbol: see text] × B = λB.

Linoleic acid improves the robustness of cells in agitated cultures

The murine hybridoma (CC9C10) was subjected to high shear rates in a spinner flask to determine the effect of various culture additives on cell survival. At 500 rpm, the half-life of the viable cell concentration in a low protein serum-free medium was 50 min. Both bovine serum albumin and Pluronic F-68 had a significant effect in protecting cells under these conditions. The effects of the two supplements were additive, so that in the presence of both supplements there was minimal cell damage at 500 rpm. The survival rate of cells grown in media supplemented with linoleic acid improved significantly under high stirring rates. Cells grown for one passage in 50 muM linoleic acid and stirred at 500 rpm had a significantly higher survival rate than control cells. For cells grown over 5 passages in 25 muM linoleic acid, the survival rate at 470 rpm was x3 greater than that determined for control cells. This difference gradually decreased at higher stirring rates up to 610 rpm when the half-life of the viable cell population was reduced to approximately 10 min. Supplementation of cultures with linoleic acid has previously been shown to result in incorporation into all three cellular lipid fractions - polar, non-polar and free fatty acid (Butler et al., 1997). Our explanation for the increased survivability of the cells at high agitation rates in the presence of linoleic acid is that the structural lipid components of the cell including the outer membrane attained a higher unsaturated/saturated ratio which was more robust than that of control cells.

Calibrated cylindrical Mach probe in a plasma wind tunnel

A simple cylindrical Mach probe is described along with an independent calibration procedure in a magnetized plasma wind tunnel. A particle orbit calculation corroborates our model. The probe operates in the weakly magnetized regime in which probe dimension and ion orbit are of the same scale. Analytical and simulation models are favorably compared with experimental calibration.

An isolate and sequence database of infectious haematopoietic necrosis virus (IHNV)

In the field of fish diseases, the amount of relevant information available is enormous. Internet-based databases are an excellent tool for keeping track of the available knowledge in the field. Fishpathogens.eu was launched in June 2009 with the aim of collecting, storing and sorting data on fish pathogens. The first pathogen to be included was the rhabdovirus, viral haemorrhagic septicaemia virus (VHSV). Here, we present an extension of the database to also include infectious haematopoietic necrosis virus (IHNV). The database is developed, maintained and managed by the European Community Reference Laboratory for Fish Diseases and collaborators. It is available at http://www.fishpathogens.eu/ihnv.

Observation of a helical self-organized state in a compact toroidal plasma

A nonaxisymmetric stable magnetohydrodynamic (MHD) equilibrium within a prolate cylindrical conducting boundary has been produced experimentally. It has m=1 azimuthal symmetry, helical distortion, and flat lambda profile, all in agreement with the computed magnetically relaxed minimum magnetic energy Taylor state. Despite varied initial conditions determined by two helicity injectors on the device, this same equilibrium consistently emerges as the final state. These results therefore describe a new example of self-organization in an MHD plasma.

FishPathogens.eu/vhsv: a user-friendly viral haemorrhagic septicaemia virus isolate and sequence database

A database has been created, http://www.FishPathogens.eu, with the aim of providing a single repository for collating important information on significant pathogens of aquaculture, relevant to their control and management. This database will be developed, maintained and managed as part of the European Community Reference Laboratory for Fish Diseases function. This concept has been initially developed for viral haemorrhagic septicaemia virus and will be extended in future to include information on other significant aquaculture pathogens. Information included for each isolate comprises sequence, geographical origin, host origin and useful key literature. Various search mechanisms make it easy to find specific groups of isolates. Search results can be presented in several different ways including table-based, map-based and graph-based outputs. When retrieving sequences, the user is given freedom to obtain data from any selected part of the genome of interest. The output of the sequence search can be readily retrieved as a FASTA file ready to be imported into a sequence alignment tool of choice, facilitating further molecular epidemiological study.

ERCC-1 (E) expression and its effect on survival in patients (pts) receiving concurrent cisplatin (C) and radiation (R) for locally advanced head and neck cancer (HNC)

e17033

Background: E is a DNA repair gene involved in the nucleotide excision repair pathway. Overexpression of E has been associated with resistance to C in patients with ovarian, gastric, and lung cancer. We retrospectively analyzed tissue from HNC pts who received concurrent C and R to determine if E expression was a significant independent predictor of survival. Methods: Eligible HNC pts had squamous cell histology and received definitive concurrent C and R at the Dallas VAMC. Tissue was immunostained for E using ERCC-1,clone 8F, 1:100 dilution (Abcam, Cat#ab2356, Cambridge, MA) diluted in ChemMate buffer (Ventana Medical Systems, Tucson, AZ) on a BenchMarkXT automated immunostainer using the UltraVIEW system with horseradish peroxidase and diaminobenzidine (DAB) chromogen (Ventana Medical Systems, Tucson, AZ) per the standard protocol of the UT Southwestern Pathology Immunohistochemistry Laboratory. E scoring was determined by 2 pathologists blinded to clinical outcomes. Scoring was as follows: 0 = 0% of tumor nuclei were positive, 1+ = less than 50%, 2+ = 50–75% and 3+ = 75–100%. Results: 73 consecutively treated patients were analyzed. Median age 59 (range 41 - 80); 99% male; 7% stage II, 19% stage III, 73% stage IV; primary site - 4% oral cavity, 56% oropharynx, 14% hypopharynx, 23% larynx, 3% nasopharynx; Tumor grade - 60% moderately differentiated, 4% well differentiated, 15% poorly differentiated, 21% not specified; Performance status 0–25%, 1–45%, 2–8%, unknown-22%; E scoring was 0 in 0%, 1+ (14%), 2+ (42%), 3+ (44%). In univariate analysis, E staining 3+ was not predictive of survival with a hazard ratio (HR) of .796 (95% CI .44–1.43; p = 0.44). In multivariate analysis, the only significant predictor was hypopharynx with a HR of 3.18 (95% CI 1.02–9.88; p = 0.046). HR for age > 60 was 2.16 (95% CI .96–4.86; p = 0.06). E staining 3+ was not predictive of survival with a HR of .69 (95% CI .3–1.56; p = 0.37). Median survival (MS) for the whole group was 2.8 years (y); 5y survival - 41%. MS for the E 3+ pts - 2.1y; 5y survival 38%. MS for the E < 3+ pts - 2.9y; 5y survival 44% (p = not significant). Conclusions: In our retrospective review of HNC patients receiving concurrent C and R, E staining was not a significant predictor of survival.

No significant financial relationships to disclose.

Absence of telomere shortening and oxidative DNA damage in the young adult offspring of women with pre-gestational type 1 diabetes

AIMS/HYPOTHESIS

The offspring of mothers with pre-gestational type 1 diabetes (PGDM) may be at increased risk of glucose intolerance and cardiovascular disease in childhood. The underlying causes of these observations, and whether they persist into adulthood, are unknown. The aim of the present study was to test the hypothesis that fetal chromosomal telomere oxidative DNA damage resulting from maternal PGDM programmes the offspring towards a senescent phenotype that is detectable in young adulthood.

METHODS

We studied 21 young adult offspring (age 16-23 years) with a maternal history of PGDM and 23 age- and weight-matched controls with no maternal history of diabetes. All participants underwent anthropometric assessments, a standard 75 g OGTT, measurement of peripheral blood mononuclear cell and skin fibroblast telomere length, fibroblast senescence, cell DNA damage (by determination of 8-oxoguanine levels using flow cytometry), plasma lipoprotein profiles (determined by nuclear magnetic resonance) and plasma levels of soluble adhesion molecules and inflammatory markers.

RESULTS

The groups did not differ significantly with respect to anthropometric measures, glucose tolerance, fasting and 2 h plasma insulin levels during OGTT, estimated peripheral insulin resistance, peripheral blood mononuclear cell or fibroblast telomere length, DNA damage or senescence in vitro, plasma NMR lipoprotein profiles or levels of high-sensitivity C-reactive protein. Plasma concentrations of soluble intercellular adhesion molecule 1 (sICAM-1; p < 0.05) and IL-6 (p = 0.08) were higher in the PGDM offspring.

CONCLUSIONS/INTERPRETATION

Young adult offspring of mothers with PGDM do not differ in terms of glucose tolerance, DNA damage or telomere length from controls of the same weight and BMI. This does not preclude such abnormalities at an earlier age, but there is no evidence of telomere damage as a pre-programming mechanism in the young adults enrolled in this study.

Enhanced energy confinement and performance in a low-recycling tokamak

Extensive lithium wall coatings and liquid lithium plasma-limiting surfaces reduce recycling, with dramatic improvements in Ohmic plasma discharges in the Current Drive Experiment-Upgrade. Global energy confinement times increase by up to 6 times. These results exceed confinement scalings such as ITER98P(y,1) by 2-3 times, and represent the largest increase in energy confinement ever observed for an Ohmic tokamak plasma. Measurements of Dalpha emission indicate that global recycling coefficients decrease to approximately 0.3, the lowest documented for a magnetically confined hydrogen plasma.

Isolation, culture, and characterisation of human macular inner choroidal microvascular endothelial cells

AIM

To develop a method for the reliable isolation of adult human macular inner choroidal endothelial cells (ICECs) and to subsequently characterise them for their expression of a range of endothelial cell associated surface markers.

METHOD

Human ICECs were isolated after manual dissection of maculas from fresh human posterior segments. Following enzyme digestion to form a single cell suspension, the ICECs were isolated using anti-CD31 coated Dynabeads. The isolated cells were grown in culture and examined for typical endothelial cell morphology, surface expression of vWf, CD 31, CD 105, VEGF receptors 1 and 2, and expression of E-selectin after stimulation with TNF-alpha. The cells were also examined for their ability to form fenestrations and capillary-like tubes in Matrigel.

RESULTS

The method enabled the rapid isolation of viable cells that demonstrated typical endothelial cobblestone morphology in culture. The cells stained positive for CD31, vWf, CD105, VEGF receptors 1 and 2, and E-selectin (after stimulation with TNF-alpha). The cells stained negative for alpha smooth muscle actin and fibroblast surface protein. The cells also developed fenestrations when cultured on fibronectin coated plates and formed capillary-like tubes structures when cultured on Matrigel.

CONCLUSIONS

This technique isolates cells from the human macular inner choroid that display features consistent with vascular endothelial cells. These cells could subsequently be used to further the understanding of the pathophysiological mechanisms of diseases of the inner choroid, such as choroidal neovascularisation.

Regulation of differentiation of the tracheobronchial epithelium

The study of differentiation has been the domain of embryologists and developmental biologists and, in the pulmonary field, the concern of neonatologists. Why should those of us who are neither be interested in differentiation of the epithelium lining the conducting airways? The reason is that injury to the airway epithelium and disruption of its steady state and its normal differentiation are common occurrences in both acute episodes of infection and during chronic diseases such as chronic obstructive pulmonary disease and asthma. Thus, it is important to know how injury is repaired and which are the critical mechanisms that control and regulate differentiation.

Regulation of mucous differentiation and mucin gene expression in the tracheobronchial epithelium

The goal of our studies is to elucidate mechanisms that control and modulate mucous differentiation and mucin gene expression in the conducting airways. We used cultures of normal human tracheobronchial epithelial (NHTBE) cells that were shown to secrete two major airway mucins, namely MUC5AC and MUC5B as well as several other secretory products. Mucous differentiation and expression of MUC2, MUC5AC, MUC5B and MUC7, but not MUCi, MUC4, and MUC8 mucin genes, were shown to be retinoic acid- (RA) or retinol-dependent. We found that RA control of mucin genes was mediated by the retinoid acid receptors RAR alpha and, to a lesser extent, by RAR gamma. Our studies also showed that other important bioregulators such as thyroid hormone (T3) and epidermal growth factor (EGF) modulate basal expression of mucin genes, interacting with RA in a concentration-dependent manner. T3, which binds to thyroid receptors (TRs) belonging to the same superfamily of steroid hormone nuclear receptors as the RARs, inhibits mucin gene expression, particularly MUC5AC. One possible mechanism of this T3 effect is downregulation of RAR proteins, which are critical for mucin gene expression. However, we also found that T3 inhibits MUC5AC transcription.EGF, which had previously been shown to stimulate mucin expression and mucin secretion in cultured rat tracheal epithelial (RTE) cells, inhibited mucin secretion in human bronchial epithelial cell cultures. This effect was EGF concentration- and time-dependent and was progressively abolished by increasing the RA concentration. Subsequent studies suggested that the inhibitory effects of high concentrations of EGF may result from selective reduction of MUC5AC expression. These studies thus point to potentially important species differences in the mechanisms regulating mucous production, and they also confirm previous findings indicating differential regulation of MUC5AC and MUC5B gene expression.

Regulation of mucin gene expression in human tracheobronchial epithelial cells by thyroid hormone

We reported previously that the expression of the gene encoding MUC5AC mucin in human airway epithelial cells is controlled by retinoic acid via the retinoic acid receptor (RAR)-alpha and that 3,3',5-tri-iodothyronine (T(3)) inhibits the expression of MUC5AC. The purpose of the present study was to identify mechanisms mediating the effect of T(3). T(3) has been shown to inhibit gene expression via several mechanisms, either by enhancing or repressing the transcription of target genes or by the regulation of post-transcriptional events. Results showed that T(3) strongly inhibited MUC5AC-driven luciferase activity in normal human tracheobronchial epithelial cells that had been transiently transfected with a MUC5AC-luciferase reporter construct; however, it did not affect MUC5AC mRNA stability. These results indicate that T(3) suppresses MUC5AC expression at the transcriptional level. An analysis of deletion constructs showed that deletion of the region downstream of 3 kb resulted in markedly decreased levels of MUC5AC transcription in the absence of T(3) (i.e. under control conditions) as well as a loss of responsiveness to the inhibitory effects of T(3). This suggests that this region might contain elements important for the activation as well as the repression of MUC5AC transcription. To determine whether T(3) modulates retinoic-acid-dependent MUC5AC transcription via an alteration in the abundance of retinoid receptor proteins, we examined the type and abundance of these receptors in nuclear extracts of airway epithelial cells grown in the presence or absence of T(3). Western blots showed that T(3) markedly decreased several types of retinoid receptor while not affecting T(3) receptor proteins. Consistent with this finding were gel-shift assays revealing a decrease in RAR-retinoic acid response element complexes obtained from T(3)-treated cells. We propose that T(3) might inhibit retinoid-dependent MUC5AC expression by decreasing retinoid receptor levels and thereby decreasing the transcriptional activation of this gene for mucins.