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Dive into the research topics where Machelle D. Wilson is active.

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Featured researches published by Machelle D. Wilson.


Radiology | 2014

Differentiation of Ovarian Endometriomas from Hemorrhagic Cysts at MR Imaging: Utility of the T2 Dark Spot Sign

Michael T. Corwin; Eugenio O. Gerscovich; Ramit Lamba; Machelle D. Wilson; John P. McGahan

PURPOSE To determine sensitivity and specificity of the T2 dark spot sign in helping to distinguish endometriomas from other hemorrhagic adnexal lesions. MATERIALS AND METHODS This HIPAA-compliant, institutional review board-approved retrospective study, with informed consent waived, included 56 women (mean age, 38.8 years; range, 18-66 years). With a radiology database search of pelvic magnetic resonance images from December 16, 2002, to July 24, 2012, 74 cystic hemorrhagic adnexal lesions with hyperintense signal on T1-weighted images were identified. Lesions were excluded if they had solid enhancing components. Final diagnosis was established with pathologic analysis for all endometriomas and neoplasms. Hemorrhagic cysts were diagnosed with pathologic analysis (n = 7), follow-up imaging (n = 13), or prior ultrasonography (n = 5). Two radiologists independently reviewed cases and recorded the presence or absence of T2 shading and T2 dark spots. T2 dark spots were defined as discrete, well-defined markedly hypointense foci within the adnexal lesion on T2-weighted images. Sensitivity, specificity, and positive and negative predictive values of the T2 dark spot sign in distinguishing endometriomas from nonendometrioma hemorrhagic lesions were calculated. RESULTS Sixteen of 45 endometriomas (36%), zero of 25 hemorrhagic cysts, and two of four neoplasms (50%) (all serous cystadenomas) demonstrated T2 dark spots. Forty-two of 45 endometriomas (93%), 12 of 25 hemorrhagic cysts (48%), and four of four neoplasms (100%) demonstrated T2 shading. Sensitivity, specificity, positive predictive value, and negative predictive value of T2 dark spots for differentiating endometriomas from other hemorrhagic cystic ovarian masses were 36% (95% confidence interval [CI]: 19.8, 51.3), 93% (95% CI: 83.9, 100), 89% (95% CI: 63.9, 98.1), and 48% (95% CI: 34.8, 61.8), respectively, and for T2 shading, they were 93% (95% CI: 84.0, 100), 45% (95% CI: 27.8, 61.9), 72% (95% CI: 58.9, 83.0), and 81% (95% CI: 53.7, 95.0), respectively. CONCLUSION The T2 dark spot sign has high specificity for chronic hemorrhage and is useful to differentiate endometriomas from hemorrhagic cysts. The T2 shading sign is sensitive but not specific for endometriomas. Online supplemental material is available for this article.


BMJ Open | 2013

Statin use and asthma control in patients with severe asthma

Amir A. Zeki; Justin M. Oldham; Machelle D. Wilson; Olga M. Fortenko; Vishal Goyal; Ayan Patel; Nicholas J. Kenyon

Objectives We hypothesised that severe asthmatics taking a statin drug, in addition to inhaled corticosteroids/long-acting β-agonist inhaler therapy, would have better asthma symptom control and improved lung function compared to their controls. Study design A retrospective, cross-sectional study of 165 patients with severe asthma seen from 2001–2008. Hierarchical linear and logistic regression models were used for modelling fitting. Setting University of California, Davis Medical Center (Sacramento, California, USA). Academic, single-centre, severe asthma subspecialty clinic. Participants 612 screened, 223 eligible and 165 adult patients were included in the final study (N=165; 31 statin users and 134 non-users). Primary and secondary outcome measures The primary endpoint was asthma control as measured by the Asthma Control Test (ACT). The secondary endpoints included lung function, symptoms and the need for corticosteroid burst and peripheral eosinophil count. Results At baseline, statin users compared to non-users were older, had lower lung function (FEV1% predicted, FEV1, forced vital capacity and FEF25–75%) and had a higher prevalence of comorbid conditions. Statin use was associated with more aspirin and ipratropium inhaler use than in non-users. Patients in both groups were obese (body mass index ≥ 30). Statin users had better asthma symptom control compared to non-users (higher adjusted mean ACT score by 2.2±0.94 points, p<0.02). Median statin use was for 1 year. There were no statistically significant differences in lung function, corticosteroid or rescue bronchodilator use or peripheral eosinophilia between the two groups. Conclusions In our severe asthma referral population, statin users already taking inhaled controller therapy achieved better asthma control compared to non-users. The implications of this study is that patients with severe asthma could potentially benefit from added statin treatment. Because our study population was on average obese, the obese severe asthmatic may be a viable asthma subphenotype for further studies. Prospective randomised clinical trials evaluating the safety and efficacy of statins in severe asthma are warranted.


IEEE Transactions on Geoscience and Remote Sensing | 2004

Classification of contamination in salt marsh plants using hyperspectral reflectance

Machelle D. Wilson; Susan L. Ustin; David M. Rocke

In this paper, we compare the classification effectiveness of two relatively new techniques on data consisting of leaf-level reflectance from five species of salt marsh and two species of crop plants (in four experiments) that have been exposed to varying levels of different heavy metal or petroleum toxicity, with a control treatment for each experiment. If these methodologies work well on leaf-level data, then there is hope that they will also work well on data from air- and spaceborne platforms. The classification methods compared were support vector classification (SVC) of exposed and nonexposed plants based on the spectral reflectance data, and partial least squares compression of the spectral reflectance data followed by classification using logistic discrimination (PLS/LD). The statistic we used to compare the effectiveness of the methodologies was the leave-one-out cross-validation estimate of the prediction error. Our results suggest that both techniques perform reasonably well, but that SVC was superior to PLS/LD for use on hyperspectral data and it is worth exploring as a technique for classifying heavy-metal or petroleum exposed plants for the more complicated data from air- and spaceborne sensors.


Nutrients | 2015

Relationships among Food Label Use, Motivation, and Dietary Quality

Lisa M. Soederberg Miller; Diana Cassady; Elizabeth A. Applegate; Laurel Beckett; Machelle D. Wilson; Tanja N. Gibson; Kathleen Ellwood

Nutrition information on packaged foods supplies information that aids consumers in meeting the recommendations put forth in the US Dietary Guidelines for Americans such as reducing intake of solid fats and added sugars. It is important to understand how food label use is related to dietary intake. However, prior work is based only on self-reported use of food labels, making it unclear if subjective assessments are biased toward motivational influences. We assessed food label use using both self-reported and objective measures, the stage of change, and dietary quality in a sample of 392 stratified by income. Self-reported food label use was assessed using a questionnaire. Objective use was assessed using a mock shopping task in which participants viewed food labels and decided which foods to purchase. Eye movements were monitored to assess attention to nutrition information on the food labels. Individuals paid attention to nutrition information when selecting foods to buy. Self-reported and objective measures of label use showed some overlap with each other (r = 0.29, p < 0.001), and both predicted dietary quality (p < 0.001 for both). The stage of change diminished the predictive power of subjective (p < 0.09), but not objective (p < 0.01), food label use. These data show both self-reported and objective measures of food label use are positively associated with dietary quality. However, self-reported measures appear to capture a greater motivational component of food label use than do more objective measures.


Britannia | 1974

The Roman Fortress at Longthorpe

Sheppard Frere; J. K. St. Joseph; D. Charlesworth; R. Goodburn; B.R. Hartley; B.J. Marples; J. N. L. Myres; R. Reece; Machelle D. Wilson

The Roman military site at Longthorpe, west of Peterborough, was discovered by observation from the air in 1961: no traces now remain on the surface. Excavations between 1967 and 1973 have shown that a 27-acre fortress with timber buildings, accommodating a legionary vexillation together with auxiliary troops, was succeeded by an 11-acre fort. The period of occupation extended from c. 44/8 to c. 62. Crop marks observed from the air at Orton Stanch, 400 m. south-east of the fortress, have led to the discovery of a native farmstead. Excavations there by Messrs. A. Challands, G. B. Dannell and Dr. J. P. Wild have shown that agricultural activities were intermitted for the period of the occupation of the fortress, the settlement being replaced by a large industrial establishment or worksdepot involved in pottery manufacture and possibly in bronze-working with clear military connections. The present report describes the excavation of the fortress: the industrial site is to be published in a future volume of Britannia .


BMC Medical Education | 2012

Medical students’ attitudes toward gay men

Kabir Singh Matharu; Richard L. Kravitz; Graham T. McMahon; Machelle D. Wilson; Faith T. Fitzgerald

BackgroundHealthcare providers’ attitudes toward sexual minorities influence patient comfort and outcomes. This study characterized medical student attitudes toward gay men, focusing on behavior, personhood, gay civil rights, and male toughness.MethodsA cross-sectional web-based anonymous survey was sent to medical students enrolled at the University of California, Davis (N = 371) with a response rate of 68%.ResultsFew respondents expressed negative attitudes toward gay men or would deny them civil rights. More negative responses were seen with respect to aspects of intimate behavior and homosexuality as a natural form of sexual expression. Men and students younger than 25 years old were more likely to endorse negative attitudes toward behavior as well as more traditional views on male toughness.ConclusionsWe show that an important minority of students express discomfort with the behavior of gay men and hold to a narrow construction of male identity. These findings suggest that competency training must move beyond conceptual discussions and address attitudes toward behaviors through new pedagogical approaches.


Infection and Immunity | 2014

Phenotypic Differences of Cryptococcus Molecular Types and Their Implications for Virulence in a Drosophila Model of Infection

George R. Thompson; Nathaniel D. Albert; Greg Hodge; Machelle D. Wilson; Jane E. Sykes; Derek J. Bays; Carolina Firacative; Wieland Meyer; Dimitrios P. Kontoyiannis

ABSTRACT Compared to Cryptococcus neoformans, little is known about the virulence of the molecular types in Cryptococcus gattii. We compared in vitro virulence factor production and survival data using a Drosophila model of infection to further characterize the phenotypic features of different cryptococcal molecular types. Forty-nine different isolates were inoculated into wild-type flies and followed for survival. In vitro, isolates were assessed for growth at 30 and 37°C, melanin production, capsule size, resistance to H2O2, and antifungal susceptibility. A mediator model was used to assess molecular type and virulence characteristics as predictors of survival in the fly model. VGIII was the most virulent molecular type in flies (P < 0.001). At 30°C, VGIII isolates grew most rapidly; at 37°C, VNI isolates grew best. C. gattii capsules were larger than those of C. neoformans (P < 0.001). Mediator model analysis found a strong correlation of Drosophila survival with molecular type and with growth at 30°C. We found molecular-type-specific differences in C. gattii in growth at different temperatures, melanin production, capsule size, ability to resist hydrogen peroxide, and antifungal susceptibility, while growth at 30°C and the VGIII molecular type were strongly associated with virulence in a Drosophila model of infection.


Ecotoxicology and Environmental Safety | 2003

Modeling uncertainty in the measurement of low-level analytes in environmental analysis

David M. Rocke; Blythe Durbin; Machelle D. Wilson; Henry D. Kahn

The use of analytical chemistry measurements in environmental monitoring is dependent on an assessment of measurement error. Models for variation in measurements are needed to quantify uncertainty in measurements, set limits of detection, and preprocess data for more sophisticated analysis in prediction, classification, and clustering. This article explains how a two-component error model can be used to accomplish all of these objectives. In addition, we present applications to quantitating biomarkers of exposure to toxic substances using gene expression microarrays.


Circulation-heart Failure | 2014

Correlates of Quality of Life in Rural Patients With Heart Failure

Thomas S. Nesbitt; Sahar Doctorvaladan; Jeffrey A. Southard; Satinder Singh; Anne Fekete; Kate Marie; Debra K. Moser; Michelle M. Pelter; Susan Robinson; Machelle D. Wilson; Lawton S. Cooper; Kathleen Dracup

Background—There is abundant research indicating poor physical, psychological, and social functioning of patients with chronic heart failure (HF), a reality that can lead to poor health-related quality of life (QoL). Little is known about the experience of rural patients with HF. Methods and Results—This study was part of a randomized clinical trial titled Rural Education to Improve Outcomes in Heart Failure (REMOTE-HF) designed to test an education and counseling intervention to improve self-care in patients with HF. We evaluated 612 rural patients. Multiple validated questionnaires were administered to assess patient perceptions of health and health literacy. Baseline factors were collected and compared with baseline QoL measures only. Patients’ health-related QoL was assessed using the Minnesota Living with Heart Failure scale. The data were analyzed using a general linear model to test the association of various patient characteristics with QoL in rural patients with HF. Patients were 65.8 (+12.9) years of age. The majority were men (58.7%), married (56.4%), and had completed a high-school education (80.9%). Factors associated with reduced QoL among this population include geographic location, younger age, male sex, higher New York Heart Association class, worse HF knowledge, poorer perceived control, and symptoms of depression or anxiety. The data provided no evidence of an association between left ventricular ejection fraction and QoL. Conclusions—This study of rural patients with HF confirms previously identified factors associated with perceptions of QoL. However, further study is warranted with an urban control group. Clinical Trial Registration—URL: http://www.clinicaltrials.gov. Unique identifier: NCT00415545.


Archives of Otolaryngology-head & Neck Surgery | 2014

Competing Causes of Death and Medical Comorbidities Among Patients With Human Papillomavirus-Positive vs Human Papillomavirus-Negative Oropharyngeal Carcinoma and Impact on Adherence to Radiotherapy

C.B. Hess; D.L. Rash; Megan E. Daly; D. Gregory Farwell; John W. Bishop; Andrew T. Vaughan; Machelle D. Wilson; Allen M. Chen

IMPORTANCE Survival of patients with head and neck cancer can be affected by competing causes of mortality, as well as comorbidities that result in radiation treatment interruptions. OBJECTIVE To discern how differences in preexisting medical and psychosocial comorbidities potentially influence adherence to radiation therapy according to human papillomavirus (HPV) status. DESIGN, SETTING, AND PARTICIPANTS Retrospective analysis at a comprehensive cancer center of 162 consecutive patients with locally advanced squamous cell carcinoma of the oropharynx treated with primary chemoradiation (n = 95) or primary surgery followed by adjuvant radiation (n = 67). Immunostaining for p16 was used to determine HPV status. MAIN OUTCOMES AND MEASURES Difference in alcohol, tobacco, and marijuana use was compared between patients with HPV-positive and HPV-negative tumors, as well as the prevalence of the following comorbidities: diabetes mellitus, chronic obstructive pulmonary disease (COPD), anxiety disorder, and major depression. The number of total missed treatment days was analyzed as both a continuous and categorical variable. RESULTS Rates of self-reported heavy alcohol use (47% vs 16%; P = .02) and any marijuana use (47% vs 23%; P = .003) were significantly higher among HPV-negative patients. Fifty-four percent of HPV-positive patients self-identified as never smokers, compared with only 12% of HPV-negative patients (P < .001). HPV-negative patients had more missed treatment days (mean, 2.8 vs 1.7 days; P = .02), as well as an increased rate of at least 5 missed days (24% vs 10%; P = .04), and higher prevalences of COPD (12% vs 7%; P = .37) and anxiety disorder (12% vs 6%; P = .35). CONCLUSIONS AND RELEVANCE Pronounced differences exist in lifestyle habits between patients with HPV-negative and HPV-positive oropharyngeal cancer at diagnosis. These differences, as well as those of medical and psychosocial burden, may contribute to observed discrepancies in treatment adherence and need to be considered in outcomes reporting and clinical trial design.

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John P. McGahan

University of Texas Southwestern Medical Center

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Laurel Beckett

University of California

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Elizabeth Zhu

University of California

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Jennifer Brown

University of California

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Ramit Lamba

University of California

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