1,810 research outputs found
A mechanistic study of the ECā² mechanism ā the split wave in cyclic voltammetry and square wave voltammetry
In this paper, a detailed investigation of electrochemical reactions coupled with homogenous chemical steps using cyclic voltammetry (CV) and square wave voltammetry (SWV) was carried out to study the electrocatalytic (ECā) mechanism. In CV, parameters including scan rate, electrode material and redox reactant were investigated while in SWV, parameters including substrate concentrations and frequencies were altered to demonstrate ECā mechanism. Mechanistic studies focused on the ECā mechanism using L-cysteine with ferrocenecarboxylic acid and 1,1 ā²-ferrocenedicarboxylic acid respectively. Voltammetric responses were recorded and under conditions of high chemical rate constant and low substrate concentration, a split wave was observed in both CV and SWV studies
An Actor-Based Model of Social Network Influence on Adolescent Body Size, Screen Time, and Playing Sports
Recent studies suggest that obesity may be ācontagiousā between individuals in social networks. Social contagion (influence), however, may not be identifiable using traditional statistical approaches because they cannot distinguish contagion from homophily (the propensity for individuals to select friends who are similar to themselves) or from shared environmental influences. In this paper, we apply the stochastic actor-based model (SABM) framework developed by Snijders and colleagues to data on adolescent body mass index (BMI), screen time, and playing active sports. Our primary hypothesis was that social influences on adolescent body size and related behaviors are independent of friend selection. Employing the SABM, we simultaneously modeled network dynamics (friendship selection based on homophily and structural characteristics of the network) and social influence. We focused on the 2 largest schools in the National Longitudinal Study of Adolescent Health (Add Health) and held the school environment constant by examining the 2 school networks separately (Nā=ā624 and 1151). Results show support in both schools for homophily on BMI, but also for social influence on BMI. There was no evidence of homophily on screen time in either school, while only one of the schools showed homophily on playing active sports. There was, however, evidence of social influence on screen time in one of the schools, and playing active sports in both schools. These results suggest that both homophily and social influence are important in understanding patterns of adolescent obesity. Intervention efforts should take into consideration peersā influence on one another, rather than treating āhigh riskā adolescents in isolation
Factors Associated with Severe Late Toxicity After Concurrent Chemoradiation for Locally Advanced Head and Neck Cancer: An RTOG Analysis
Purpose
Concurrent chemoradiotherapy (CCRT) for squamous cell carcinoma of the head and neck (SCCHN) increases both local tumor control and toxicity. This study evaluates clinical factors that are associated with and might predict severe late toxicity after CCRT.
Methods
Patients were analyzed from a subset of three previously reported RTOG trials of concurrent chemoradiotherapy for locally advanced SCCHN (RTOG 91-11; 97-03; and 99-14). Severe late toxicity was defined in this secondary analysis as chronic Grade 3-4 pharyngeal/laryngeal toxicity (RTOG/EORTC late toxicity scoring system) and/or requirement for a feeding tube ā„2 years after registration and/or potential treatment-related death (e.g. pneumonia) within 3 years. Case-control analysis was performed, with a multivariable logistic regression model that included pre-treatment and treatment potential factors.
Results
A total of 230 patients were evaluable for this analysis, 99 cases (patients with severe late toxicities) and 131 controls; thus 43% of evaluable patients had a severe late toxicity. On multivariable analysis, significant variables correlated with the development of severe late toxicity were older age (odds ratio 1.05 per year; p = 0.001); advanced T-stage (odds ratio 3.07; p=0.0036); larynx/hypopharynx primary site (odds ratio 4.17; p=0.0041); and neck dissection after chemo-RT (odds ratio 2.39; p=0.018).
Conclusions
Severe late toxicity following CCRT is common. Older age, advanced T-stage, and larynx/ hypopharynx primary site were strong independent risk
American Society of Clinical Oncology. Machtay, M. et al: J. Clin. Oncol. 26 (21), 2008:3582-3589
Correlation of Neck Circumference with BMI and Waist Circumference in a High-Risk Urban Cohort
Background
Problem Statement: Obesity is a global epidemic requiring accurate ongoing clinical assessment, as it increases risk of multiple health conditions, such as CVD. Body mass index (BMI) is the most widely used anthropometric measure. Waist circumference (WC) is an accurate measure of visceral fat. Neck circumference (NC) is a newer, simple assessment tool positively correlated with percent body fat, BMI and WC. NC is easier to measure than WC, and unaffected by external factors like lean muscle mass for BMI, and abdominal distension, respiration, and patient discomfort for WC.
Hypothesis: NC, less studied in black patients, who are at higher risk of CVD, is hypothesized to correlate with BMI and WC in a predominantly black, urban patient cohort.
Project Objectives: Investigate the feasibility of integrating NC measurements into routine clinical assessments, emphasizing its simplicity and potential advantages Explore the correlation of NC with BMI and WC in a predominantly black, urban patient cohort with a higher risk of obesity-related conditions
ACR appropriateness criteriaĀ® nasal cavity and paranasal sinus cancers
The American College of Radiology (ACR) Appropriateness Criteria are evidenceābased guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peerāreviewed journals and the application of wellāestablished methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment. Here, we present the Appropriateness Criteria for cancers arising in the nasal cavity and paranasal sinuses (maxillary, sphenoid, and ethmoid sinuses). This includes clinical presentation, prognostic factors, principles of management, and treatment outcomes. Controversies regarding management of cervical lymph nodes are discussed. Rare and unusual nasal cavity cancers, such as esthesioneuroblastoma and sinonasal undifferentiated carcinomas, are included. Ā© 2016 American College of Radiology. Head Neck, 2016 Ā© 2016 Wiley Periodicals, Inc. Head Neck 39: 407ā418, 2017Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/136245/1/hed24639.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/136245/2/hed24639_am.pd
Sequential chemotherapy and intensity-modulated radiation therapy in the management of locoregionally advanced nasopharyngeal carcinoma: Experience of 370 consecutive cases
<p>Abstract</p> <p>Introduction</p> <p>To investigate the outcome of locoregionally advanced nasopharyngeal carcinoma (NPC) treated with intensity-modulated radiation therapy (IMRT) after induction chemotherapy, with or without concomitant chemotherapy.</p> <p>Methods</p> <p>Between August 2003 and March 2007, 370 patients with locoregionally advanced NPC were treated with IMRT. Presenting stages were stage IIB in 62, stage III in 197, and stage IVA/B in 111 patients. All patients except for 36 patients with cervical lymphadenopathy of 4 cm or less in diameter received 2 cycles of cisplatin-based neoadjuvant chemotherapy. Forty-eight patients received cisplatin-based concurrent chemotherapy as well.</p> <p>Results</p> <p>With a median follow-up time of 31 months (range 5 to 61 months), the 3-year local control, regional control, metastasis-free survival (MFS), disease-free survival (DFS) and overall survival (OS) rates were 95%, 97%, 86%, 81% and 89%, respectively. Multivariate analyses revealed that both age (ā¤ 60 vs. >60) and N-classification are significant prognosticators for OS (P = 0.001, hazard ratio [HR] 2.395, 95% confidence interval [CI] 1.432-4.003; P = 0.012, hazard ratio [HR] 2.614, 95% confidence interval [CI] 1.235-5.533); And N-classification is the only significant predicative factor for MFS (P = 0.002, [HR] 1.99, 95% CI 1.279-3.098). T-classification and concurrent chemotherapy were not significant prognostic factors for local/regional control, MFS, DFS, or OS. Subgroup analysis revealed that concurrent chemotherapy provided no significant benefit to IMRT in locoregionally advanced NPC, but was responsible for higher rates of grade 3 or 4 acute toxicities (50% vs. 29.8%, P < 0.005). No grade 3 or 4 late toxicity including xerostomia was observed. However, two patients treated with IMRT and neoadjuvant but without concurrent and adjuvant chemotherapy died of treatment related complications.</p> <p>Conclusion</p> <p>IMRT following neoadjuvant chemotherapy produced a superb outcome in terms of local control, regional control, MFS, DFS, and OS rates in patients with stage IIB to IVB NPC. Effective treatment strategy is urgently needed for distant control in patients diagnosed with locoregionally advanced NPC.</p
Evo-devo of human adolescence: beyond disease models of early puberty
Despite substantial heritability in pubertal development, much variation remains to be explained, leaving room for the influence of environmental factors to adjust its phenotypic trajectory in the service of fitness goals. Utilizing evolutionary development biology (evo-devo), we examine adolescence as an evolutionary life-history stage in its developmental context. We show that the transition from the preceding stage of juvenility entails adaptive plasticity in response to energy resources, other environmental cues, social needs of adolescence and maturation toward youth and adulthood. Using the evolutionary theory of socialization, we show that familial psychosocial stress fosters a fast life history and reproductive strategy rather than early maturation being just a risk factor for aggression and delinquency. Here we explore implications of an evolutionary-developmental-endocrinological-anthropological framework for theory building, while illuminating new directions for research
Clinically Actionable Hypercholesterolemia and Hypertriglyceridemia in Children with Nonalcoholic Fatty Liver Disease
OBJECTIVE:
To determine the percentage of children with nonalcoholic fatty liver disease (NAFLD) in whom intervention for low-density lipoprotein cholesterol or triglycerides was indicated based on National Heart, Lung, and Blood Institute guidelines.
STUDY DESIGN:
This multicenter, longitudinal cohort study included children with NAFLD enrolled in the National Institute of Diabetes and Digestive and Kidney Diseases Nonalcoholic Steatohepatitis Clinical Research Network. Fasting lipid profiles were obtained at diagnosis. Standardized dietary recommendations were provided. After 1 year, lipid profiles were repeated and interpreted according to National Heart, Lung, and Blood Institute Expert Panel on Integrated Guidelines for Cardiovascular Health and Risk Reduction. Main outcomes were meeting criteria for clinically actionable dyslipidemia at baseline, and either achieving lipid goal at follow-up or meeting criteria for ongoing intervention.
RESULTS:
There were 585 participants, with a mean age of 12.8 years. The prevalence of children warranting intervention for low-density lipoprotein cholesterol at baseline was 14%. After 1 year of recommended dietary changes, 51% achieved goal low-density lipoprotein cholesterol, 27% qualified for enhanced dietary and lifestyle modifications, and 22% met criteria for pharmacologic intervention. Elevated triglycerides were more prevalent, with 51% meeting criteria for intervention. At 1 year, 25% achieved goal triglycerides with diet and lifestyle changes, 38% met criteria for advanced dietary modifications, and 37% qualified for antihyperlipidemic medications.
CONCLUSIONS:
More than one-half of children with NAFLD met intervention thresholds for dyslipidemia. Based on the burden of clinically relevant dyslipidemia, lipid screening in children with NAFLD is warranted. Clinicians caring for children with NAFLD should be familiar with lipid management
CCAAT/Enhancer-Binding Protein Ī³ Is a Critical Regulator of IL-1Ī²-Induced IL-6 Production in Alveolar Epithelial Cells
CCAAT/enhancer binding protein Ī³ (C/EBPĪ³) is a member of the C/EBP family of transcription factors, which lacks known activation domains. C/EBPĪ³ was originally described as an inhibitor of C/EBP transactivation potential. However, previous study demonstrates that C/EBPĪ³ augments the C/EBPĪ² stimulatory activity in lipopolysaccharide induction of IL-6 promoter in a B lymphoblast cell line. These data indicate a complexing functional role for C/EBPĪ³ in regulating gene expression. Furthermore, the expression and function of C/EBPĪ³ during inflammation are still largely unknown. In this study, we demonstrate that C/EBPĪ³ activation was induced by IL-1Ī² treatment in lung epithelial cells. Importantly, we demonstrate for the first time that C/EBPĪ³ plays a critical role in regulating IL-1Ī²-induced IL-6 expression in both mouse primary alveolar type II epithelial cells and a lung epithelial cell line, MLE12. We further provide the evidence that C/EBPĪ³ inhibits IL-6 expression by inhibiting C/EBPĪ² but not NF-ĪŗB stimulatory activity in MLE12 cells. These findings suggest that C/EBPĪ³ is a key transcription factor that regulates the IL-6 expression in alveolar epithelial cells, and may play an important regulatory role in lung inflammatory responses
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