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Dartmouth, Lebanon

Diuk-Wasser M.A.,The New School | Hoen A.G.,Community and Family Medicine | Cislo P.,The New School | Brinkerhoff R.,University of Richmond | And 11 more authors.
American Journal of Tropical Medicine and Hygiene | Year: 2012

The geographic pattern of human risk for infection with Borrelia burgdorferi sensu stricto, the tick-borne pathogen that causes Lyme disease, was mapped for the eastern United States. The map is based on standardized field sampling in 304 sites of the density of Ixodes scapularis host-seeking nymphs infected with B. burgdorferi, which is closely associated with human infection risk. Risk factors for the presence and density of infected nymphs were used to model a continuous 8 km +8 km resolution predictive surface of human risk, including confidence intervals for each pixel. Discontinuous Lyme disease risk foci were identified in the Northeast and upper Midwest, with a transitional zone including sites with uninfected I. scapularis populations. Given frequent under- and over-diagnoses of Lyme disease, this map could act as a tool to guide surveillance, control, and prevention efforts and act as a baseline for studies tracking the spread of infection. Copyright © 2012 by The American Society of Tropical Medicine and Hygiene. Source

Bynum J.P.W.,Dartmouth Institute for Health Policy and Clinical Practice | Andrews A.,Dartmouth Institute | Sharp S.,Dartmouth Institute | McCullough D.,Community and Family Medicine | Wennberg J.E.,Dartmouth Institute
Health Affairs | Year: 2011

Meeting the medical and social needs of elderly people is likely to be costly, disruptive, and at odds with personal preferences if efforts to do so are not well coordinated. We compared two different models of primary care in four different continuing care retirement communities. In the first model, used in one community, the physicians and two parttime nurse practitioners delivered clinical care only at that site, covered all settings within it, and provided all after-hours coverage. In the second model, used in three communities, on-site primary care physician hours were limited; the same physicians also had independent practices outside the retirement community; and after-hours calls were covered by all members of the practices, including physicians who did not practice on site. We found that residents in the first model had two to three times fewer hospitalizations and emergency department visits. Only 5 percent of those who died did so in a hospital, compared to 15 percent at the other sites and 27 percent nationally. These findings provide insight into what is possible when medical care is highly integrated into a residential retirement setting. © 2011 Project HOPE-The People-to-People Health Foundation, Inc. Source

Yan J.,Indiana University | Du L.,Indiana University | Kim S.,Indiana University | Risacher S.L.,Indiana University | And 4 more authors.
Bioinformatics | Year: 2014

Motivation: Imaging genetics is an emerging field that studies the influence of genetic variation on brain structure and function. The major task is to examine the association between genetic markers such as single-nucleotide polymorphisms (SNPs) and quantitative traits (QTs) extracted from neuroimaging data. The complexity of these datasets has presented critical bioinformatics challenges that require new enabling tools. Sparse canonical correlation analysis (SCCA) is a bi-multivariate technique used in imaging genetics to identify complex multi-SNP-multi-QT associations. However, most of the existing SCCA algorithms are designed using the soft thresholding method, which assumes that the input features are independent from one another. This assumption clearly does not hold for the imaging genetic data. In this article, we propose a new knowledge-guided SCCA algorithm (KG-SCCA) to overcome this limitation as well as improve learning results by incorporating valuable prior knowledge. Results: The proposed KG-SCCA method is able to model two types of prior knowledge: one as a group structure (e.g. linkage disequilibrium blocks among SNPs) and the other as a network structure (e.g. gene co-expression network among brain regions). The new model incorporates these prior structures by introducing new regularization terms to encourage weight similarity between grouped or connected features. A new algorithm is designed to solve the KG-SCCA model without imposing the independence constraint on the input features. We demonstrate the effectiveness of our algorithm with both synthetic and real data. For real data, using an Alzheimer's disease (AD) cohort, we examine the imaging genetic associations between all SNPs in the APOE gene (i.e. top AD gene) and amyloid deposition measures among cortical regions (i.e. a major AD hallmark). In comparison with a widely used SCCA implementation, our KG-SCCA algorithm produces not only improved cross-validation performances but also biologically meaningful results. © The Author 2014. Published by Oxford University Press. All rights reserved. Source

Von Reyn C.F.,Dartmouth Hitchcock Medical Center | Mtei L.,Muhimbili University of Health and Allied Sciences | Arbeit R.D.,Tufts University | Waddell R.,Dartmouth Hitchcock Medical Center | And 8 more authors.
AIDS | Year: 2010

Objective: To determine whether a multiple-dose series of an inactivated whole cell mycobacterial vaccine, Mycobacterium vaccae, can prevent HIV-associated tuberculosis. Design and Methods: The DarDar trial was a randomized, placebo-controlled, double-blind trial. The study was carried in an outpatient facility in Dar es Salaam, Tanzania. HIV-infected patients with CD4 cell counts of at least 200 cells/μl and a Bacille Calmette-Guérin scar were chosen for the study. The intervention was carried out by random 1:1 assignment to five intradermal doses of M. vaccae or placebo. Tuberculin skin tests were performed, and patients with reactions of at least 5 mm were administered isoniazid for 6 months. The main outcome measures were disseminated (primary endpoint), definite, and probable tuberculosis (secondary endpoints). Results: Two thousand thirteen individuals were randomized (1006 to M. vaccae, 1007 to placebo) and followed every 3 months for a median of 3.3 years. The trial was terminated early because of slow accrual of cases of disseminated tuberculosis and significant protection against definite tuberculosis. Hazard ratios were disseminated tuberculosis 0.52 (95% confidence interval 0.21-1.34; seven cases in M. vaccae, 13 cases in placebo; log-rank P = 0.16), definite tuberculosis 0.61 (95% confidence interval 0.39-0.96; 33 cases in M. vaccae, 52 cases in placebo; P = 0.03), and probable tuberculosis 1.17 (95% confidence interval 0.76-1.80; 48 cases in M. vaccae, 40 cases in placebo; P = 0.46). Immunization was well tolerated, with no adverse effect on CD4 cell count or HIV viral load, and no increase in the rate of serious adverse events. Conclusion: Administration of a multiple-dose series of M. vaccae to HIV-infected adults with childhood Bacille Calmette-Guérin immunization is safe and is associated with significant protection against definite tuberculosis. These results provide evidence that immunization with a whole cell mycobacterial vaccine is a viable strategy for the prevention of HIV-associated tuberculosis. © 2010 Wolters Kluwer Health | Lippincott Williams & Wilkins. Source

Tosteson A.N.A.,Community and Family Medicine | Tosteson T.D.,Community and Family Medicine | Carragee E.J.,Stanford University | Carrino J.A.,Johns Hopkins Hospital | Herzog R.J.,Hospital for Special Surgery
Spine | Year: 2013

Study Design. A retrospective cohort design. Objective. To determine whether baseline magnetic resonance imaging findings, including central/foraminal stenosis, Modic change, disc morphology, facet arthropathy, disc degeneration, nerve root impingement, and thecal sac compression, are associated with differential surgical treatment effect. Summary of Background Data. Intervertebral disc herniation remains the most common source of lumbar radiculopathy treated either with discectomy or nonoperative intervention. Although magnetic resonance imaging remains the reliable "gold standard" for diagnosis, uncertainty surrounds the relationship between magnetic resonance imaging fi ndings and treatment outcomes. Methods. Three hundred seven "complete" images from patients enrolled in a previous trial were de-identified and evaluated by 1 of 4 independent readers. Findings were compared with outcome measures including the Oswestry Disability Index. Differences in surgery and nonoperative treatment outcomes were evaluated between image characteristic subgroups and TE determined by the difference in Oswestry Disability Index scores. Results. The cohort comprised 40% females with an average age of 41.5 ( ?± 11.6) years, 61% of whom underwent discectomy for intervertebral disc herniation. Patients undergoing surgery with Modic type I endplate changes had worse outcomes ( - 26.4 vs . - 39.7 for none and - 39.2 for type 2, P = 0.002) and smaller treatment effect ( - 3.5 vs . - 19.3 for none and - 15.7 for type 2, P = 0.003). Those with compression of ≥ 1/3 showed the greatest improvement within the surgical group ( - 41.9 for ≥ 1/3 vs . - 31.6 for none and - 38.1 for < 1/3, P = 0.007) and the highest TE ( - 23 compared with - 11.7 for none and - 15.2 for < 1/3, P = 0.015). Furthermore, patients with minimal nerve root impingement demonstrated worse surgical outcomes ( - 26.5 vs . - 41.1 for "displaced" and - 38.9 for "compressed," P = 0.016). Conclusion. Among patients with intervertebral disc herniation, those with thecal sac compression of 1/3 or more had greater surgical treatment effect than those with small disc herniations and Modic type I changes. In addition, patients with nerve root "compression" and "displacement" benefi t more from surgery than those with minimal nerve root impingement. Copyright © 2013 Lippincott Williams & Wilkins. Source

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