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Recovery of information from multiple imputation: a simulation study
Katherine J Lee, John B Carlin
Emerging Themes in Epidemiology , 2012, DOI: 10.1186/1742-7622-9-3
Abstract: Simulated datasets (n？=？1000) drawn from a synthetic population were used to explore information recovery from multiple imputation in estimating the coefficient of a binary exposure variable when various proportions of data (10-90%) were set missing at random in a highly-skewed continuous covariate or in the binary exposure. Imputation was performed using multivariate normal imputation (MVNI), with a simple or zero-skewness log transformation to manage non-normality. Bias, precision, mean-squared error and coverage for a set of regression parameter estimates were compared between multiple imputation and complete case analyses.For missingness in the continuous covariate, multiple imputation produced less bias and greater precision for the effect of the binary exposure variable, compared with complete case analysis, with larger gains in precision with more missing data. However, even with only moderate missingness, large bias and substantial under-coverage were apparent in estimating the continuous covariate’s effect when skewness was not adequately addressed. For missingness in the binary covariate, all estimates had negligible bias but gains in precision from multiple imputation were minimal, particularly for the coefficient of the binary exposure.Although multiple imputation can be useful if covariates required for confounding adjustment are missing, benefits are likely to be minimal when data are missing in the exposure variable of interest. Furthermore, when there are large amounts of missingness, multiple imputation can become unreliable and introduce bias not present in a complete case analysis if the imputation model is not appropriate. Epidemiologists dealing with missing data should keep in mind the potential limitations as well as the potential benefits of multiple imputation. Further work is needed to provide clearer guidelines on effective application of this method.Statistical analysis of epidemiological data is often hindered by missing data. Multiple i
Variability in Skin Prick Test Results Performed by Multiple Operators Depends on the Device Used
Rebecca L Werther, Sharon Choo, Katherine J Lee, Debra Poole, Katrina J Allen, Mimi LK Tang
World Allergy Organization Journal , 2012, DOI: 10.1097/wox.0b013e31827e6513
Abstract: We assessed the variability of measurements from 4 commonly used single-headed skin test devices when used by multiple operators and examined whether the variability in performance was different on the back compared with the forearm.Eight adult volunteer "operators" were trained in the use of 4 devices: Greer Pick, Quintip, Stallergenes Lancet, and Feather Lancet. Each operator performed a histamine skin prick test with all devices on the backs and forearms of 5 volunteer "receivers." Variability in results was assessed using a multilevel (random effects) regression model.After controlling for variation between users and receivers, the residual variability or "measurement error" was least for the Stallergenes Lancet, closely followed by the Quintip. The Greer Pick had the greatest variability. There was greater variability in measurements on the arm compared with the back.The devices using the "puncture" method (Stallergenes Lancet, Quintip) provide less variability in results than those using a "prick" method when carried out by multiple users (Greer Pick and Feather Lancet). Testing on the back also gives less variable results compared with the arm.
Descriptive Phenotype of Obsessive Compulsive Symptoms in Males With Duchenne Muscular Dystrophy
Aaron J. Kauer,Angela J. Lee,Edward T. Buckingham,Katherine D. Mathews
- , 2018, DOI: 10.1177/0883073818774439
Abstract: Increased rates of clinically significant internalizing disorders (obsessive compulsive disorder, anxiety, and depression) have been demonstrated in males with Duchenne muscular dystrophy, and a Duchenne muscular dystrophy neuropsychiatric syndrome has been suggested. Although symptoms of depression are widely recognized, some of the other internalizing symptoms are less frequently identified. Through a retrospective chart review of 107 males with Duchenne muscular dystrophy, we identified 15 patients with obsessive compulsive disorder spectrum symptoms; 11 of those also had anxiety symptoms. Many of these patients received selective serotonin reuptake inhibitor treatment, commonly noting improvement in symptoms. Here we describe the clinical features of several patients in detail to facilitate early recognition and consideration for treatment for patients with Duchenne muscular dystrophy and internalizing psychiatric symptoms. The results of this cohort showed a significantly increased rate of obsessive compulsive disorder spectrum symptoms (14%) compared to the general population
ERP Evidence for Co-Activation of English Words during Recognition of American Sign Language Signs
Brittany Lee,Gabriela Meade,Karen Emmorey,Katherine J. Midgley,Phillip J. Holcomb
Brain Sciences | An Open Access Journal from MDPI , 2019, DOI: https://doi.org/10.3390/brainsci9060148
Abstract: Event-related potentials (ERPs) were used to investigate co-activation of English words during recognition of American Sign Language (ASL) signs. Deaf and hearing signers viewed pairs of ASL signs and judged their semantic relatedness. Half of the semantically unrelated signs had English translations that shared an orthographic and phonological rime (e.g., BAR–STAR) and half did not (e.g., NURSE–STAR). Classic N400 and behavioral semantic priming effects were observed in both groups. For hearing signers, targets in sign pairs with English rime translations elicited a smaller N400 compared to targets in pairs with unrelated English translations. In contrast, a reversed N400 effect was observed for deaf signers: target signs in English rime translation pairs elicited a larger N400 compared to targets in pairs with unrelated English translations. This reversed effect was overtaken by a later, more typical ERP priming effect for deaf signers who were aware of the manipulation. These findings provide evidence that implicit language co-activation in bimodal bilinguals is bidirectional. However, the distinct pattern of effects in deaf and hearing signers suggests that it may be modulated by differences in language proficiency and dominance as well as by asymmetric reliance on orthographic versus phonological representations. View Full-Tex
The Course of Well-Being in Romantic Relationships: Predicting Positive Affect in Dating Participants  [PDF]
Katherine J. Bao
Psychology (PSYCH) , 2012, DOI: 10.4236/psych.2012.312A161
Abstract:

People use different methods to make themselves happier, but their attempts at lasting happiness are often thwarted by the hedonic adaptation process. We examined changes in well-being over 8 weeks in participants who were involved in romantic relationships and those who were not. On average, both groups declined in well-being over time, but the relationship group experienced more positive emotions overall. High positive affect was predicted by higher aspirations, higher passionate love, and being in a same-ethnicity relationship. None of the variables we measured significantly predicted changes in positive affect over time, which may be due to the short duration of the study.

Estimation of PSA Half-Life Following Salvage Radiation Therapy  [PDF]
Ajay B. Patel, Katherine S. Tzou, Michael G. Heckman, Colleen S. Thomas, Richard J. Lee, Nitesh Paryani, Thomas M. Pisansky, Jennifer L. Peterson, Robert C. Miller, Stephen J. Ko, Laura A. Vallow, Steven J. Buskirk
Journal of Cancer Therapy (JCT) , 2018, DOI: 10.4236/jct.2018.91002
Abstract: Background:？We aim to estimate prostate-specific antigen (PSA) half-life after salvage radiation therapy (SRT) in patients with detectable PSA after radical prostatectomy (RP). Methods: A total of 272 patients treated with salvage radiotherapy between July 1987 and July 2010 were included in this IRB approved retrospective analysis. The median pre-salvage radiotherapy dose was 0.6 ng/mL (range, 0.2 - 21.9 ng/mL), 47 patients had at least a minimum tumor stage of T3b, 29 had a Gleason score over 7, and median dose was 66.6 Gy (range, 54.0 - 72.4 Gy). Results: The estimated PSA half-life in our cohort of patients was 3.0 months (95% CI, 2.9 - 3.2 months; range, 0.5 -
Case-Control Study of Fetal Microchimerism and Breast Cancer
Vijayakrishna K. Gadi, Kathleen E. Malone, Katherine A. Guthrie, Peggy L. Porter, J. Lee Nelson
PLOS ONE , 2008, DOI: 10.1371/journal.pone.0001706
Abstract: Background Prior pregnancy is known to protect against development of breast cancer. Recent studies have demonstrated that pregnancy has the capacity to establish small numbers of immunologically active fetal-derived cells in the mother, a phenomenon known as fetal microchimerism (FMc). We asked whether presence of FMc, routinely acquired during pregnancy, is a protective factor for breast cancer. Methodology/Principal Findings DNA extracts from peripheral blood specimens were obtained from a population-based case-control study of risk factors for breast cancer in women 21 to 45 years old. Specimens were tested with quantitative PCR for presence and concentrations of male DNA presumed to derive from prior pregnancies with a male fetus. Odds ratios (OR) and 95% confidence intervals (CI) were estimated with consideration of multiple established reproductive and environmental risk factors for breast cancer. FMc results were generated on 99 parous women, 54 with primary invasive breast cancer and 45 general population controls. FMc prevalence was 56% (25/45) and 26% (14/54) in controls and cases, respectively. Women harboring FMc were less likely to have had breast cancer (OR = 0.29, 95% CI 0.11–0.83; p = 0.02, adjusting for age, number of children, birth of a son, history of miscarriage, and total DNA tested). In addition, FMc concentrations were higher in controls versus cases (p = 0.01). Median concentrations were 2 (0–78) and 0 (0–374) fetal genomes/106 maternal genomes in controls and cases, respectively. Conclusions Results suggest that the enigma of why some parous women are not afforded protection from breast cancer by pregnancy might in part be explained by differences in FMc. Mechanistic studies of FMc-derived protection against breast cancer are warranted.
Corporate Social Responsibility and Access to Policy élites: An Analysis of Tobacco Industry Documents
Gary J. Fooks ,Anna B. Gilmore,Katherine E. Smith,Jeff Collin,Chris Holden,Kelley Lee
PLOS Medicine , 2011, DOI: 10.1371/journal.pmed.1001076
Abstract: Background Recent attempts by large tobacco companies to represent themselves as socially responsible have been widely dismissed as image management. Existing research supports such claims by pointing to the failings and misleading nature of corporate social responsibility (CSR) initiatives. However, few studies have focused in depth on what tobacco companies hoped to achieve through CSR or reflected on the extent to which these ambitions have been realised. Methods and Findings Iterative searching relating to CSR strategies was undertaken of internal British American Tobacco (BAT) documents, released through litigation in the US. Relevant documents (764) were indexed and qualitatively analysed. In the past decade, BAT has actively developed a wide-ranging CSR programme. Company documents indicate that one of the key aims of this programme was to help the company secure access to policymakers and, thereby, increase the company's chances of influencing policy decisions. Taking the UK as a case study, this paper demonstrates the way in which CSR can be used to renew and maintain dialogue with policymakers, even in ostensibly unreceptive political contexts. In practice, the impact of this political use of CSR is likely to be context specific; depending on factors such as policy élites' understanding of the credibility of companies as a reliable source of information. Conclusions The findings suggest that tobacco company CSR strategies can enable access to and dialogue with policymakers and provide opportunities for issue definition. CSR should therefore be seen as a form of corporate political activity. This underlines the need for broad implementation of Article 5.3 of the Framework Convention on Tobacco Control. Measures are needed to ensure transparency of interactions between all parts of government and the tobacco industry and for policy makers to be made more aware of what companies hope to achieve through CSR. Please see later in the article for the Editors' Summary
A double blind, randomised placebo controlled trial of topical 2% viscous lidocaine in improving oral intake in children with painful infectious mouth conditions
Sandy M Hopper, Franz E Babl, Michelle McCarthy, Chasari Tancharoen, Katherine J Lee, Ed Oakley
BMC Pediatrics , 2011, DOI: 10.1186/1471-2431-11-106
Abstract: This study is a randomised double-blind placebo controlled trial of children between 6 months and 8 years of age with painful infectious mouth conditions defined as gingivostomatitis (herpetic or non herpetic), ulcerative pharyngitis, herpangina and hand foot and mouth disease as assessed by the treating clinician in association with a history of poor oral fluid intake. It will be conducted at a single tertiary paediatric emergency department in Melbourne Australia.20 patients have already been randomised to receive 2% lidocaine or placebo in a pilot study to determine the sample size in a preplanned adaptive design. A further 80 patients will be randomised to receive either 2% lidocaine or placebo. The placebo agent is identical to lidocaine in terms of appearance, flavour and smell. All clinical and research staff involved, patients and their parents will be blinded to treatment allocation.The primary endpoint is the amount of fluid ingested by each child, expressed in ml/kg, within 60 minutes from the time of administration of the study mixture. Secondary endpoints are the proportion of patients ingesting 5 ml/kg and 10 ml/kg at 30 and 60 minutes after drug administration and the incidence of adverse events. Longer term outcomes will include the proportion of patients requiring hospital admission and length of emergency department stay.This trial will define the role of 2% lidocaine in the treatment of painful infectious mouth conditionsThe trial is registered with the Australian and New Zealand Clinical Trials Registry - ACTRN12609000566235.Painful infectious mouth conditions are a common presentation to paediatric emergency departments. These are usually viral conditions such as gingivostomatitis (herpetic and non herpetic), ulcerative pharyngitis, herpangina and hand foot and mouth disease. Most of the paediatric literature concerns primary herpetic gingivostomatitis (PHGS) caused by infection with the herpes simplex virus. Although self limiting, there is con
Anti-inflammatory action of insulin via induction of Gadd45-β transcription by the mTOR signaling pathway
Katherine D Bortoff, Adam B Keeton, J Lee Franklin, et al
Hepatic Medicine: Evidence and Research , 2010, DOI: http://dx.doi.org/10.2147/HMER.S7083
Abstract: nti-inflammatory action of insulin via induction of Gadd45-β transcription by the mTOR signaling pathway (2643) Total Article Views Authors: Katherine D Bortoff, Adam B Keeton, J Lee Franklin, et al Published Date June 2010 Volume 2010:2 Pages 79 - 85 DOI: http://dx.doi.org/10.2147/HMER.S7083 Katherine D Bortoff1, Adam B Keeton1, J Lee Franklin1, Joseph L Messina1,2 1Department of Pathology, Division of Molecular and Cellular Pathology, The University of Alabama at Birmingham, Birmingham, Alabama, USA; 2Veterans Affairs Medical Center, Birmingham, Alabama, USA Abstract: Insulin regulates a large number of genes in a tissue-specific manner. We have previously identified genes modulated by insulin in the liver and in liver-derived cells that have not yet been characterized as insulin regulated, and results of these previous studies indicated that numerous genes are induced by insulin via the MEK-ERK pathway. We now describe new studies indicating that Gadd45-β can be induced by acute insulin treatment. Although other regulators of Gadd45-β expression may utilize the MEK-ERK pathway, the data indicate that insulin utilizes signaling pathways separate from either MEK-ERK, PI3-K, or p38 signaling pathways in the regulation of Gadd45-β transcription. Our findings show that activation of a downstream effector of multiple signaling pathways, mTOR, was required for insulin-induction of Gadd45-β gene transcription. Increased expression of Gadd45-β can inhibit c-Jun N-terminal kinase (JNK) activity. Since TNFα is increased during inflammation, and acts, at least in part, via the JNK signaling pathway, insulin induction of Gadd45-β suggests a mechanism for the anti-inflammatory actions of insulin.
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