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At least 1,675 records · Page 93

Emerging (and converging) pathways in Parkinson's disease: keeping mitochondrial wellness

The selective cell loss in the ventral component of the substantia nigra pars compacta and the presence of alpha-synuclein (α-syn)-rich intraneuronal inclusions called Lewy bodies are the pathological hallmarks of Parkinson's disease (PD), the most common motor system disorder whose aetiology remains largely elusive. Although most cases of PD are idiopathic, there are rare familial forms of the disease that can be traced to single gene mutations that follow Mendelian inheritance pattern. The study of several nuclear encoded proteins whose mutations are linked to the development of autosomal recessive and dominant forms of familial PD enhanced our understanding of biochemical and cellular mechanisms contributing to the disease and suggested that many signs of neurodegeneration result from compromised mitochondrial function. Here we present an overview of the current understanding of PD-related mitochondrial dysfunction including defects in bioenergetics and Ca{sup 2+} homeostasis, mitochondrial DNA mutations, altered mitochondrial dynamics and autophagy. We emphasize, in particular, the convergence of many “apparently” different pathways towards a common route involving mitochondria. Understanding whether mitochondrial dysfunction in PD represents the cause or the consequence of the disease is challenging and will help to define the pathogenic processes at the basis of the PD onset and progression. - Highlights: • Mitochondrial dysfunctions are a common feature of neurodegenerative diseases. • Many familial PD related proteins ensure mitochondrial function. • Mutations in PD genes differently affect mitochondria related activities.

60 APPLIED LIFE SCIENCES↗

A unified mechanism for plant polyketide biosynthesis derived from in silico modeling

Highlights: • A unitary mechanism for the cyclization of tetraketides in stilbene and chalcone synthase. • The identification of an active water that functions as a “Claisen switch” in chalcone synthase. • QM-MM and FMO analysis of model tetraketide ligands highlighting common and disparate components of binding pockets and cyclization sites in stilbene and chalcone synthase. The polyketide synthases found in a variety of plants and fungi provide a varied source of biologically active compounds of pharmacological and medicinal interest. Stilbene synthase and chalcone synthase catalyze the formation of a common tetraketide intermediate, but use different cyclization mechanisms to produce distinct and separate natural products. While key structural differences have been identified to explain this functional diversity, a fuller explication of the factors responsible for this mechanistic disparity is required. Based on the energetics of our models of the bound tetraketides, and our structural analysis of the active sites we propose that a key tautomeric conversion provides a mechanistic framework common to both cyclizations. A previously unidentified active water molecule facilitates cyclization in chalcone synthase through a Claisen mechanism. Such a “Claisen switch” is comparable to the previously characterized “aldol switch” mechanism proposed for the biosynthesis of resveratrol in stilbene synthase.

60 APPLIED LIFE SCIENCES↗

Surface chemistry connecting heterogeneous catalysis, photocatalysis and plasmonic catalysis

We report chemical reactions catalyzed by solid catalysts have recently expanded rapidly from traditional heterogeneous catalytic reactions to photocatalytic reactions and further to plasmonic-catalytic reactions, however, the fundamental understanding of the commonalities and differences among heterogeneous catalysis, photocatalysis and plasmonic catalysis is not well established. Adsorption/reactions/desorption on solid catalyst surfaces commonly occur during these catalytic processes, thus surface chemistry of solid catalysts can be taken to bridge the fundamental understanding among heterogeneous catalysis, photocatalysis and plasmonic catalysis. The purpose of this themed topic is to report novel results and review literatures’ results on surface chemistry of heterogeneous catalysis, photocatalysis and plasmonic catalysis with an attempt to summarize the commonalities and discuss the differences. Also, we believe that the themed topic will be of great interest and exert high imparts in the surface chemistry and catalysis field.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

RANSBox: A zero-dimensional modular software package for Reynolds-averaged Navier-Stokes modeling

RANSBox is a zero-dimensional software package for Reynolds-averaged Navier-Stokes (RANS) modeling developed at Lawrence Livermore National Laboratory to support common implementation of RANS models across a variety of host codes with different numerical schemes and code bases. Herein this work describes the key features of RANSBox including “model-agnostic integration,” which allows new models to be implemented in RANSBox and quickly deployed to host codes without additional changes to the host code base. Three one-dimensional test problems with analytical asymptotic properties are described which can be used to verify correctness of RANSBox integration. Results for these problems are then compared across different RANS models in a single code and across different codes with a common RANS model. By using a common model implementation in RANSBox, host codes with different numerical schemes and formal orders of accuracy are demonstrated to predict the expected behavior for the three test problems.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

Characterizing Long COVID: Deep Phenotype of a Complex Condition

Background: Numerous publications describe the clinical manifestations of post-acute sequelae of SARS-CoV-2 (PASC or "long COVID"), but they are difficult to integrate because of heterogeneous methods and the lack of a standard for denoting the many phenotypic manifestations. Patient-led studies are of particular importance for understanding the natural history of COVID-19, but integration is hampered because they often use different terms to describe the same symptom or condition. This significant disparity in patient versus clinical characterization motivated the proposed ontological approach to specifying manifestations, which will improve capture and integration of future long COVID studies. Methods: The Human Phenotype Ontology (HPO) is a widely used standard for exchange and analysis of phenotypic abnormalities in human disease but has not yet been applied to the analysis of COVID-19. Funding: We identified 303 articles published before April 29, 2021, curated 59 relevant manuscripts that described clinical manifestations in 81 cohorts three weeks or more following acute COVID-19, and mapped 287 unique clinical findings to HPO terms. We present layperson synonyms and definitions that can be used to link patient self-report questionnaires to standard medical terminology. Long COVID clinical manifestations are not assessed consistently across studies, and most manifestations have been reported with a wide range of synonyms by different authors. Across at least 10 cohorts, authors reported 31 unique clinical features corresponding to HPO terms; the most commonly reported feature was Fatigue (median 45.1%) and the least commonly reported was Nausea (median 3.9%), but the reported percentages varied widely between studies. Interpretation: Translating long COVID manifestations into computable HPO terms will improve analysis, data capture, and classification of long COVID patients. If researchers, clinicians, and patients share a common language, then studies can be compared/pooled more effectively. Furthermore, mapping lay terminology to HPO will help patients assist clinicians and researchers in creating phenotypic characterizations that are computationally accessible, thereby improving the stratification, diagnosis, and treatment of long COVID.

60 APPLIED LIFE SCIENCES↗

Evaluating EIA systems' effectiveness: A state of the art

Highlights: • State of the art covering 59 articles from 1996 to June 2016. • Reviews effectiveness concepts and methodologies used to explore them. • Major gaps and trends identified for four effectiveness dimensions. • Discusses multidimensional EIA studies as future of the research field. - Abstract: Analyzing the effectiveness of environmental impact assessment (EIA) is an important theme in EIA literature. Over the course of its development, the manifold term “effectiveness” has been delineated into four dimensions: Procedural, substantive, transactive, and normative. The present state of the art review covers not only studies about these concepts, but also the methods used to test them. It analyzes trends in 64 studies over a 20-year period. It is observed that results oriented research is more common than process oriented, but given the links between results and processes, procedural effectiveness remains the lens through which policy solutions are analyzed. Future research is recommended comparing developing and developed countries as well as studies focusing on subnational EIA systems. Serious gaps in the literature remain, such as developing methods to evaluate the direct impact of EIA on decision-making and how to integrate the pluralism found in the EIA process for sustainable ends. Reliance on perceptual survey and interview methods is common for substantive and normative effectiveness studies. The least studied dimension, transactive dimension, requires more study, specifically the cost efficiency of EIA. Promisingly, multidimensional studies are becoming more common that highlight linkages among these dimensions, although the nature of these linkages must be tested with more case studies.

54 ENVIRONMENTAL SCIENCES↗

Metal mixtures in urban and rural populations in the US: The Multi-Ethnic Study of Atherosclerosis and the Strong Heart Study

Background: Natural and anthropogenic sources of metal exposure differ for urban and rural residents. We searched to identify patterns of metal mixtures which could suggest common environmental sources and/or metabolic pathways of different urinary metals, and compared metal-mixtures in two population-based studies from urban/sub-urban and rural/town areas in the US: the Multi-Ethnic Study of Atherosclerosis (MESA) and the Strong Heart Study (SHS). Methods: We studied a random sample of 308 White, Black, Chinese-American, and Hispanic participants in MESA (2000–2002) and 277 American Indian participants in SHS (1998–2003). We used principal component analysis (PCA), cluster analysis (CA), and linear discriminant analysis (LDA) to evaluate nine urinary metals (antimony [Sb], arsenic [As], cadmium [Cd], lead [Pb], molybdenum [Mo], selenium [Se], tungsten [W], uranium [U] and zinc [Zn]). For arsenic, we used the sum of inorganic and methylated species (∑As). Results: All nine urinary metals were higher in SHS compared to MESA participants. PCA and CA revealed the same patterns in SHS, suggesting 4 distinct principal components (PC) or clusters (∑As-U-W, Pb-Sb, Cd-Zn, Mo-Se). In MESA, CA showed 2 large clusters (∑As-Mo-Sb-U-W, Cd-Pb-Se-Zn), while PCA showed 4 PCs (Sb-U-W, Pb-Se-Zn, Cd-Mo, ∑As). LDA indicated that ∑As, U, W, and Zn were the most discriminant variables distinguishing MESA and SHS participants. Conclusions: In SHS, the ∑As-U-W cluster and PC might reflect groundwater contamination in rural areas, and the Cd-Zn cluster and PC could reflect common sources from meat products or metabolic interactions. Among the metals assayed, ∑As, U, W and Zn differed the most between MESA and SHS, possibly reflecting disproportionate exposure from drinking water and perhaps food in rural Native communities compared to urban communities around the US. - Highlights: • We identified and compared environmental sources of urinary metals in MESA and SHS. • ∑As-U-W in SHS may reflect groundwater contamination in rural areas. • Cd-Zn in SHS may reflect common sources from meat products or metabolic interaction. • ∑As, U, W, and Zn differed the most between MESA and SHS participants.

54 ENVIRONMENTAL SCIENCES↗

Ambient air pollution and pregnancy outcomes: A comprehensive review and identification of environmental public health challenges

There is a growing number of studies on the association between ambient air pollution and adverse pregnancy outcomes, but their results have been inconsistent. Consequently, a comprehensive review of this research area is needed. There was a wide variability in studied pregnancy outcomes, observed gestational windows of exposure, observed ambient air pollutants, applied exposure assessment methods and statistical analysis methods Gestational duration, preterm birth, (low) birth weight, and small for gestational age/intrauterine growth restriction were most commonly investigated pregnancy outcomes. Gestational windows of exposure typically included were whole pregnancy period, 1st, 2nd, 3rd trimester, first and last gestational months. Preterm birth was the outcome most extensively studied across various gestational windows, especially at the beginning and at the end of pregnancy. Particulate matter, nitrogen dioxide, ozone, and carbon monoxide were the most commonly used markers of ambient air pollution. Continuous monitoring data were frequently combined with spatially more precisely modelled estimates of exposure. Exposure to particulate matter and ozone over the entire pregnancy was significantly associated with higher risk for preterm birth: the pooled effect estimates were 1.09 (1.03–1.16) per 10 μg/m{sup 3} increase in particulate matter with an aerodynamic diameter of 10 µm or less (PM{sub 10}){sub ,}1.24 (1.08–1.41) per 10 μg/m{sup 3} increase in particulate matter with an aerodynamic diameter of 2.5 µm or less (PM{sub 2.5}), and 1.03 (1.01–1.04) per 10 ppb increase in ozone. For pregnancy outcomes other than PTB, ranges of observed effect estimates were reported due to smaller number of studies included in each gestational window of exposure. Further research is needed to link the routine pregnancy outcome data with spatially and temporally resolved ambient air pollution data, while adjusting for commonly defined confounders. Methods for assessing exposure to mixtures of pollutants, indoor air pollution exposure, and various other environmental exposures, need to be developed.

54 ENVIRONMENTAL SCIENCES↗

The clumped-isotope geochemistry of exhumed marbles from Naxos, Greece

Exhumation and accompanying retrograde metamorphism alter the compositions and textures of metamorphic rocks through deformation, mineral–mineral reactions, water–rock reactions, and diffusion-controlled intra- and inter-mineral atomic mobility. Here, we demonstrate that these processes are recorded in the clumped- and single-isotope (δ 13 C and δ 18 O) compositions of marbles, which can be used to constrain retrograde metamorphic histories. We collected 27 calcite and dolomite marbles along a transect from the rim to the center of the metamorphic core-complex of Naxos (Greece), and analyzed their carbonate single- and clumped-isotope compositions. The majority of Δ 47 values of whole-rock samples are consistent with exhumation- controlled cooling of the metamorphic complex. However, the data also reveal that water–rock interaction, deformation driven recrystallization and thermal shock associated with hydrothermal alteration may considerably impact the overall distribution of Δ 47 values. We analyzed specific carbonate fabrics influenced by deformation and fluid–rock reaction to study how these processes register in the carbonate clumped-isotope system. Δ 47 values of domains drilled from a calcite marble show a bimodal distribution. Low Δ 47 values correspond to an apparent temperature of 260 °C and are common in static fabrics; high Δ 47 values correspond to an apparent temperature of 200 °C and are common in dynamically recrystallized fabrics. We suggest that the low Δ 47 values reflect diffusion-controlled isotopic reordering during cooling, whereas high Δ 47 values reflect isotopic reordering driven by dynamic recrystallization. We further studied the mechanism by which dynamic recrystallization may alter Δ 47 values by controlled heating experiments. Results show no significant difference between laboratory reactions rates in the static and dynamic fabrics, consistent with a mineral-extrinsic mechanism, in which slip along crystal planes was associated with atomic-scale isotopic reordering in the calcite lattice. An intrinsic mechanism (enhanced isotopic reordering rate in deformed minerals) is contraindicated by these experiments. We suggest that Δ 47 values of dynamically recrystallized fabrics that form below the diffusion-controlled blocking-temperature for calcite constrain the temperature of deformation. We find that Δ 47 -based temperatures of static fabrics from Naxos marbles are ~60–80 °C higher than commonly observed in slowly cooled metamorphic rocks, and would suggest cooling rates of ~10 5 °CMyr -1 . A similar thermal history is inferred for dolomite marbles from the core vicinity, which preserve apparent temperatures up to 200 °C higher than a typical blocking temperature (~300 °C). This finding could be explained by a hydrothermal event driving a brief thermal pulse and locally resetting Δ 47 values. Rapid cooling of the core-complex region is consistent with a compilation of published cooling ages and a new apatite U–Th/He age, associating the thermal event with the emplacement of a granodiorite pluton at ~12 Ma.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

A microstructural signature of the coesite-quartz transformation: New insights from high-pressure experiments and EBSD

Ultra-high pressure (UHP) metamorphism is difficult to identify in continental crust as few petrological barometers are suitable for dominantly felsic lithologies. In such cases, burial to extreme depths is commonly identified through the preservation of coesite, a high-pressure polymorph of SiO 2 that typically forms at depths exceeding ∼ 100 km (i.e., > 2 GPa pressure). Unfortunately, coesite readily transforms to quartz upon exhumation, meaning that UHP terranes may often be overlooked. While some studies have suggested that quartz may inherit an orientation signature indicative of former coesite, both the specific nature of this signature and the conditions favouring its development remain uncertain. Here, to address this problem, we combine electron backscatter diffraction analysis of natural and experimental samples to explore microstructural evolution across the coesite-quartz phase transformation. We demonstrate that neighbouring domains of quartz commonly feature an 84 ± 4° rotation of [c] axes around the pole of a common {m} plane. This orientation relationship is a product of epitaxy, whereby the {$11\bar{2}2$} Japan twin plane in quartz nucleates on the (010) plane in coesite. In supercell simulations, the nucleation of Japan twins can be explained by the energetically favourable alignment of quartz tetrahedra on parental coesite tetrahedra. Through experiments, we demonstrate that this signature emerges over a broad range of conditions, regardless of the availability of nucleation sites (e.g., grain boundaries) or the density of crystal lattice defects (e.g., dislocations). Overall, our work provides a quantitative and unambiguous tool for identifying UHP terranes from quartz in isolation.

Coesite↗

Context and mitigation of lost circulation during geothermal drilling in diverse geologic settings

Lost circulation is one of the most common and expensive problems facing geothermal energy development, representing up to 30% of drilling costs. We examined drilling records from four geothermal fields—McGinness Hills in central Nevada, Don A. Campbell and Steamboat Hills in western Nevada, and Puna Geothermal Venture on the Big Island of Hawai'i— to identify geologies most prone to lost circulation, as well as common mitigation strategies. Depths of lost circulation events varied, but their frequency often increased in the production interval. Lost circulation commonly occurred near fault intersections, and heavily faulted fields like McGinness Hills and Don A. Campbell showed secondary mineralization within approximately 100 m (328 ft) or less of where circulation was lost. Lost circulation mitigation strategies included using locally available materials (e.g., cotton seed hulls) as well as more expensive proprietary lost circulation materials, cement plugs above the reservoir, and drilling blind with aerated, polymer-based mud in the production zone. Addressing lost circulation using a well thought out decision-making approach and materials above the reservoir will save time and cost, and provide needed well integrity. Mitigation often requires a series of steps, typically applied from perceived least expensive to most, and are dependent on the severity and location in the well where circulation was lost and availability of materials. Placing cement plugs can cure lost circulation events, however these plugs are often expensive, time-consuming, and may not be successful.

15 GEOTHERMAL ENERGY↗

Extending the Shared Socioeconomic Pathways for sub-national impacts, adaptation, and vulnerability studies

The exploration of alternative socioeconomic futures is an important aspect of understanding the potential consequences of climate change. While socioeconomic scenarios are common and, at times essential, tools for the impact, adaptation and vulnerability and integrated assessment modeling research communities, their approaches to scenario development have historically been quite distinct. However, increasing convergence of impact, adaptation and vulnerability and integrated assessment modeling research in terms of scales of analysis suggests there may be value in the development of a common framework for socioeconomic scenarios. The Shared Socioeconomic Pathways represents an opportunity for the development of such a common framework. However, the scales at which these global storylines have been developed are largely incommensurate with the sub-national scales at which impact, adaptation and vulnerability, and increasingly integrated assessment modeling, studies are conducted. Our objective for this study was to develop sub-national and sectoral extensions of the global SSP storylines in order to identify future socioeconomic challenges for adaptation for the U.S. Southeast. A set of nested qualitative socioeconomic storyline elements, integrated storylines, and accompanying quantitative indicators were developed through an application of the Factor-Actor-Sector framework. Finally, in addition to revealing challenges and opportunities associated with the use of the SSPs as a basis for more refined scenario development, this study generated sub-national storyline elements and storylines that can subsequently be used to explore the implications of alternative subnational socioeconomic futures for the assessment of climate change impacts and adaptation.

54 ENVIRONMENTAL SCIENCES↗

Clinical–Pathologic Stage Discrepancy in Bladder Cancer Patients Treated With Radical Cystectomy: Results From the National Cancer Data Base

Purpose: To examine the accuracy of clinical staging and its effects on outcome in bladder cancer (BC) patients treated with radical cystectomy (RC), using a large national database. Methods and Materials: A total of 16,953 patients with BC without distant metastases treated with RC from 1998 to 2009 were analyzed. Factors associated with clinical–pathologic stage discrepancy were assessed by multivariate generalized estimating equation models. Survival analysis was conducted for patients treated between 1998 and 2004 (n=7270) using the Kaplan-Meier method and Cox proportional hazards models. Results: At RC 41.9% of patients were upstaged, whereas 5.9% were downstaged. Upstaging was more common in females, the elderly, and in patients who underwent a more extensive lymphadenectomy. Downstaging was less common in patients treated at community centers, in the elderly, and in Hispanics. Receipt of preoperative chemotherapy was highly associated with downstaging. Five-year overall survival rates for patients with clinical stages 0, I, II, III, and IV were 67.2%, 62.9%, 50.4%, 36.9%, and 27.2%, respectively, whereas those for the same pathologic stages were 70.8%, 75.8%, 63.7%, 41.5%, and 24.7%, respectively. On multivariate analysis, upstaging was associated with increased 5-year mortality (hazard ratio [HR] 1.80, P<.001), but downstaging was not associated with survival (HR 0.88, P=.160). In contrast, more extensive lymphadenectomy was associated with decreased 5-year mortality (HR 0.76 for ≥10 lymph nodes examined, P<.001), as was treatment at an National Cancer Institute–designated cancer center (HR 0.90, P=.042). Conclusions: Clinical–pathologic stage discrepancy in BC patients is remarkably common across the United States. These findings should be considered when selecting patients for preoperative or nonoperative management strategies and when comparing the outcomes of bladder sparing approaches to RC.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

Use of Single- versus Multiple-Fraction Palliative Radiation Therapy for Bone Metastases: Population-Based Analysis of 16,898 Courses in a Canadian Province

Purpose: There is abundant evidence that a single fraction (SF) of palliative radiation therapy (RT) for bone metastases is equivalent to more protracted and costly multiple fraction courses. Despite this, there is low utilization of SFRT internationally. We sought to determine the utilization of SFRT in a population-based, publicly funded health care system. Methods and Materials: All consecutive patients with bone metastases treated with RT during 2007 to 2011 in British Columbia (BC) were identified. Associations between utilization of SFRT and patient and provider characteristics were investigated. Results: A total of 16,898 courses of RT were delivered to 8601 patients. SFRT was prescribed 49% of the time. There were positive relationships among SFRT utilization and primary tumor group (P<.001; most commonly in prostate cancer), worse prognosis (P<.001), increasing physician experience (P<.001), site of metastases (P<.001; least for spine metastases), and area of training (P<.001; most commonly for oncologists trained in the United Kingdom). There was wide variation in the prescription of SFRT across 5 regional cancer centers, ranging from 25.5% to 73.4%, which persisted after controlling for other, potentially confounding factors (P<.001). Conclusions: The large variability in SFRT utilization across BC Cancer Agency (BCCA) cancer centers suggests there is a strong cultural effect, where physicians' use of SFRT is influenced by their colleagues' practice. SFRT use in BC was similar to that in other Canadian and western European reports but strikingly higher than in the United States. Further work is needed to standardize SFRT prescribing practices internationally for this common indication for RT, with the potential for huge health system cost savings and substantial improvements in patients' quality of life.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

Assessment of Parametrial Response by Growth Pattern in Patients With International Federation of Gynecology and Obstetrics Stage IIB and IIIB Cervical Cancer: Analysis of Patients From a Prospective, Multicenter Trial (EMBRACE)

Purpose: To assess disease response along the parametrial space according to tumor morphology in patients with International Federation of Gynecology and Obstetrics (FIGO) stage IIB and IIIB cervical cancer at the time of image-guided adaptive brachytherapy. Methods and Materials: Patients with FIGO stage IIB and IIIB cervical cancer registered as of November 2013 in the EMBRACE study were evaluated. Tumors were stratified according to morphologic subtype on magnetic resonance imaging (expansive and infiltrative), and the characteristics of those subtypes were analyzed. Parametrial involvement at diagnosis and at brachytherapy was evaluated, and the response to chemo-radiotherapy was classified as good, moderate, or poor. The response grade was compared between the 2 groups and analyzed with regard to tumor volumes, and dosimetric parameters. Results: A total of 452 patients were evaluated, of whom 186 had expansive growth type and 266 had infiltrative morphology. Patients with infiltrative tumors had more extensive disease, as indicated by a higher rate of FIGO stage IIIB disease, as well as radiologic evidence of extension into the distal parametrial space and to the pelvic side wall on magnetic resonance imaging. Cervical necrosis was more common in the infiltrative group. Good response was more common in the expansive group (34% vs 24%; P=.02), and poor response was more common in the infiltrative group (11% and 19%; P=.02). Mean gross tumor volume at diagnosis was equal in both groups (51.7 cm{sup 3}). The high-risk clinical target volume was larger in infiltrative tumors (37.9 cm{sup 3} vs 33.3 cm{sup 3}, P=.005). The mean high-risk clinical target volume D{sub 90} was slightly higher in expansive tumors (92.7 Gy and 89.4 Gy, P<.001). Conclusion: Infiltrative tumors are more advanced at presentation and respond less favorably to chemo-radiotherapy when compared with expansive tumors that are more or less equivalent in size. The use of image-guided adaptive brachytherapy allows achieving reasonably high doses in both groups.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

Outcomes of Sinonasal Cancer Treated With Proton Therapy

Purpose: To report disease outcomes after proton therapy (PT) for sinonasal cancer. Methods and Materials: Eighty-four adult patients without metastases received primary (13%) or adjuvant (87%) PT for sinonasal cancers (excluding melanoma, sarcoma, and lymphoma). Common histologies were olfactory neuroblastoma (23%), squamous cell carcinoma (22%), and adenoid cystic carcinoma (17%). Advanced stage (T3 in 25% and T4 in 69%) and high-grade histology (51%) were common. Surgical procedures included endoscopic resection alone (45%), endoscopic resection with craniotomy (12%), or open resection (30%). Gross residual disease was present in 26% of patients. Most patients received hyperfractionated PT (1.2 Gy [relative biological effectiveness (RBE)] twice daily, 99%) and chemotherapy (75%). The median PT dose was 73.8 Gy (RBE), with 85% of patients receiving more than 70 Gy (RBE). Prognostic factors were analyzed using Kaplan-Meier analysis and proportional hazards regression for multiple regression. Dosimetric parameters were evaluated using logistic regression. Serious, late grade 3 or higher toxicity was reported using the National Cancer Institute Common Terminology Criteria for Adverse Events, version 4. The median follow-up was 2.4 years for all patients and 2.7 years among living patients. Results: The local control (LC), neck control, freedom from distant metastasis, disease-free survival, cause-specific survival, and overall survival rates were 83%, 94%, 73%, 63%, 70%, and 68%, respectively, at 3 years. Gross total resection and PT resulted in a 90% 3-year LC rate. The 3-year LC rate was 61% for primary radiation therapy and 59% for patients with gross disease. Gross disease was the only significant factor for LC on multivariate analysis, whereas grade and continuous LC were prognostic for overall survival. Six of 12 local recurrences were marginal. Dural dissemination represented 26% of distant recurrences. Late toxicity occurred in 24% of patients (with grade 3 or higher unilateral vision loss in 2%). Conclusions: Dose-intensified, hyperfractionated PT with or without concurrent chemotherapy results in excellent LC after gross total resection, and results in patients with gross disease are encouraging. Patients with high-grade histology are at greater risk of death from distant dissemination. Continuous LC is a major determinant of survival justifying aggressive local therapy in nearly all cases.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

Long-Term Outcomes After Proton Beam Therapy for Sinonasal Squamous Cell Carcinoma

Purpose: Squamous cell carcinoma (SCC) is the most common sinonasal cancer and is associated with one of the poor outcomes. Proton therapy allows excellent target coverage with maximal sparing of adjacent normal tissues. We evaluated the long-term outcomes in patients with sinonasal SCC treated with proton therapy. Methods and Materials: Between 1991 and 2008, 54 patients with Stage III and IV SCC of the nasal cavity and paranasal sinus received proton beam therapy at our institution to a median dose of 72.8 Gy(RBE). Sixty-nine percent underwent prior surgical resection, and 74% received elective nodal radiation. Locoregional control and survival probabilities were estimated with the Kaplan-Meier method. Multivariate analyses were performed using the Cox proportional-hazards model. Treatment toxicity was scored using the Common Terminology Criteria for Adverse Events version 4.0. Results: With a median follow-up time of 82 months in surviving patients, there were 10 local, 7 regional, and 11 distant failures. The 2-year and 5-year actuarial local control rate was 80%. The 2-year and 5-year rates of overall survival were 67% and 47%, respectively. Only smoking status was predictive for worse locoregional control, with current smokers having a 5-year rate of 23% compared with 83% for noncurrent smokers (P=.004). Karnofsky performance status ≤80 was the most significant factor predictive for worse overall survival in multivariate analysis (adjusted hazard ratio 4.5, 95% confidence interval 1.6-12.5, P=.004). There were nine grade 3 and six grade 4 toxicities, and no grade 5 toxicity. Wound adverse events constituted the most common grade 3-4 toxicity. Conclusions: Our long-term results show that proton radiation therapy is well tolerated and yields good locoregional control for SCC of the nasal cavity and paranasal sinus. Current smokers and patients with poor performance status had inferior outcomes. Prospective study is necessary to compare IMRT with proton therapy in the treatment of sinonasal malignancy.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

Radionuclide surrogate aerosolization, resuspension and suppression in hazardous situations

Radioactive fire following nuclear accidents causes resuspension of radioactive contamination that can spread over large areas. Although many papers focus on particle deposition and resuspension, a limited number of studies model its suppression. Even less data is available for the comparison of emissions across particle size, surface, and mode of resuspension. In this study, cerium dioxide surrogate for internal hazards such as radionuclide particle matter was aerosolized into a large chamber and subsequently resuspended after sedimentation. Resuspension was induced by common modes of human movement including walking, wind, and driving on common surfaces including polyvinyl chloride (PVC), artificial grass (turf), and concrete in a 5.8 m long, 3.7 m wide and 3 m high tent. The resuspension was experimentally measured for two particle sizes (1 and 10 μm) at three different heights (0.3 m, 1.2 m, and 2.4 m) and compared across size, surface, and mode of resuspension. Particle size distribution was measured using an aerodynamic particle sizer and the resuspended particles were collected with the wetted wall cyclone aerosol collector and quantitated using inductively coupled plasma mass spectrometry. The testing was repeated with the F-500 fire retardant application to study its effect on resuspension. In this study, artificial grass flooring was found to generate the most resuspension, with walking on turf for the 1 μm particle testing yielding the highest factor overall. Concrete had the lowest resuspension, showing variations in the size distribution of aerosol as a function of height from the source resuspension factors. The application of fire retardant was found to significantly reduce surrogate resuspension, regardless of resuspension method or testing surface. Here, the results provide impactful information regarding the different modes of resuspension including human transport (walking and driving) and wind for the resuspension of radionuclide surrogate particles deposited onto common surfaces and the effect of fire retardant application on their resuspension, leading to higher levels of safety for nuclear energy plants and facilities.

42 ENGINEERING↗