616 results on '"Owens, Christopher"'
Search Results
2. Evolution of white matter hyperintensity segmentation methods and implementation over the past two decades; an incomplete shift towards deep learning
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Rahmani, Maryam, Dierker, Donna, Yaeger, Lauren, Saykin, Andrew, Luckett, Patrick H., Vlassenko, Andrei G., Owens, Christopher, Jafri, Hussain, Womack, Kyle, Fripp, Jurgen, Xia, Ying, Tosun, Duygu, Benzinger, Tammie L. S., Masters, Colin L., Lee, Jin-Moo, Morris, John C., Goyal, Manu S., Strain, Jeremy F., Kukull, Walter, Weiner, Michael, Burnham, Samantha, CoxDoecke, Tim James, Fedyashov, Victor, Fripp, Jurgen, Shishegar, Rosita, Xiong, Chengjie, Marcus, Daniel, Raniga, Parnesh, Li, Shenpeng, Aschenbrenner, Andrew, Hassenstab, Jason, Lim, Yen Ying, Maruff, Paul, Sohrabi, Hamid, Robertson, Jo, Markovic, Shaun, Bourgeat, Pierrick, Doré, Vincent, Mayo, Clifford Jack, Mussoumzadeh, Parinaz, Rowe, Chris, Villemagne, Victor, Bateman, Randy, Fowler, Chris, Li, Qiao-Xin, Martins, Ralph, Schindler, Suzanne, Shaw, Les, Cruchaga, Carlos, Harari, Oscar, Laws, Simon, Porter, Tenielle, O’Brien, Eleanor, Perrin, Richard, Kukull, Walter, Bateman, Randy, McDade, Eric, Jack, Clifford, Morris, John, Yassi, Nawaf, Bourgeat, Pierrick, Perrin, Richard, Roberts, Blaine, Villemagne, Victor, Fedyashov, Victor, and Goudey, Benjamin
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- 2024
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3. Rural–Urban Differences in HIV Sexual Risk Behaviors and HIV Service Utilization Among Adolescent Sexual Minority Males in the United States
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Owens, Christopher, Hurtado, Jr., Manuel, Moskowitz, David A., Mustanski, Brian, and Macapagal, Kathryn
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- 2024
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4. Adult Stakeholders’ Perspectives on the Content, Design, and Dissemination of Sexual and Gender Minority Adolescent-Centered PrEP Campaigns
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Ma, Junye, Owens, Christopher, Valadez-Tapia, Silvia, Brooks, John J., Pickett, Jim, Walter, Nathan, and Macapagal, Kathryn
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- 2024
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5. A Comparison of Rural and Urban Primary Care Physicians’ Comfort Level of Providing Sexual Healthcare Practices to Adolescent Patients
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Owens, Christopher, Mullen, Cody, and Hubach, Randolph D.
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- 2023
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6. The HIV Pre-Exposure Prophylaxis Information-Motivation-Behavioral Skills of Parents of Adolescent Sexual Minority Males and Transgender and Gender Diverse Adolescents
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Owens, Christopher, Hoffman, Matt, Grant, Morgan J., Carter, Kaileigh, and Hubach, Randolph D.
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- 2023
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7. A Qualitative Study of First HIV Test Experiences Among Sexual and Gender Minority Adolescents
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Macapagal, Kathryn, Ma, Junye, Matson, Margaret, Chinander, Allie, Owens, Christopher, Wongsomboon, Val, Saber, Rana, and Mustanski, Brian
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- 2023
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8. Quality of Life in Patients With Chronic Limb-Threatening Ischemia Treated With Revascularization
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Menard, Matthew T., Farber, Alik, Powell, Richard J., Rosenfield, Kenneth, Conte, Michael S., Hamza, Taye H., Kaufman, John A., Cziraky, Mark J., Creager, Mark A., Dake, Michael D., Jaff, Michael R., Reid, Diane, Sopko, George, White, Christopher J., Strong, Michael B., van Over, Max, Chisci, Emiliano, Goodney, Philip P., Gray, Bruce, Kayssi, Ahmed, Siracuse, Jeffrey J., Choudhry, Niteesh K., Maurao, Mick, Muluk, Satish, Belkin, Michael, Lyden, Sean, Shishehbor, Mehdi, Bajakian, Danielle, Duwayri, Yazan, Bowens, Nina, Nypaver, Timothy, Mukherjee, Dipankar, Obrand, Daniel, LaMuraglia, Glenn, Kalra, Manju, Bernardo, Nelson, Barshes, Neal, Lipsitz, Evan, Jenkins, J. Stephen, Gasper, Warren, Owens, Christopher, Pomposelli, Frank, Rogers, Kevin, Vouyouka, Ageliki, Passman, Marc, Pena, Constantino, Ramaiah, Venkatesh, Hoch, John, Bersin, Robert, Hayes, Greg, Ho, Karen, Shah, Aamir, Lum, Ying Wie, Darling, R. Clement, III, Aalami, Oliver, Zhou, Wei, Patel, Parag, Aziz, Abdulhameed, Halloran, Brian, Jung, Enjae, Mitchell, Erica, Turba, Ulku Cenk, Choi, Eric, Hiramoto, Jade, Owens, Christopher, Milner, Ross, Crawford, Robert, Ucuzian, Areck, Henke, Peter, Chaer, Rabih, Lahiri (Adams), Julie, Gelabert, Hugh, Safian, Robert, Mena-Hurtado, Carlos, Ihnat, Daniel, Rowe, Vincent, Kashyap, Vikram, Shaw, Palma, Korngold, Ethan, Lindsay, Thomas, Winkelaar, Gerrit, Mell, Matthew, DuVal, Bruce, Aziz, Faisal, Reed, Amy, Nazzal, Munier, Schanzer, Andres, Hamdan, Allen, Smeds, Matthew, Kalish, Jeffrey, Slaiby, Jeffrey, Androes, Mark, Hanover, Tod, Motaganahalli, Raghu, Chang, Catherine, Hye, Robert, Alexander, Jason, Ansel, Gary, Bohannon, Todd, Desai, Sapan, Hodgson, Kim, Hood, Douglas, Guzman, Randolph Pl, Giles, Kristina, Shah, Samir, Hawkins, Beau, Brothers, Thomas Edward, Azizzadeh, Ali, Charlton-Ouw, Kristofer, Khan, Sophia, Brooke, Benjamin S., Kabutey, Nii-Kabu, Sachar, Ravish, Dosluoglu, Hasan, Berman, Scott, Blebea, John, Taubman, Kevin, Douville, Yvan, Cox, Mitchell W., Davis, Joseph, Caps, Michael, Schneider, Peter, Abou-Zamzam, Ahmed, Feldman, Robert, von Mering, Gregory, Tan, Tze-Woei, Virk, Chiranjiv S., Zhang, Wayne, Bacharach, Michael, Seidman, Craig, Iafrati, Mark, Findeiss, Laura, Bailey, Charles, Shames, Murray, Lane, John, Baril, Donald, Hass, Stephen, Stone, Patrick, Sharma, Aditya, Tracci, Margaret, Mackenzie, Kent, Stoner, Michael, Starr, Jean, McAllister, David, Singh, Niten, Tsai, Shirling, Kinlay, Scott, Macsata, Robyn, Neville, Richard, Rundback, John, McGinigle, Kate, Vallabhaneni, Raghu, Espinoza, Andrey, Azarbal, Amir, Longo, G. Matthew, Kovach, Richard, Soukas, Peter, Metzger, Chris, Artis, Andre, Bachinsky, William, Armstrong, Ehrin, Hattler, Brack, Chandra, Venita, Schor, Jonathan, Bianchi, Christian, Kiang, Sharon, Ben-Arie, Eyal, Verta, Michael, Wilkinson, Julia, Hurie, Justin, Kopriva, David, Molnar, Robert, Chun, Linda Jun, Azene, Ezana, Davis, Clark, Blazick, Elizabeth, Henao, Steve, Proffitt, Trent, Herman, Christine, Nathan, Derek, Chang, Robert, Lane, John, Mureebe, Leila, Chen, Jerry, Semel, Marcus, Fecteau, Scott, Mehta, Manish, Nagpal, Sudhir, Shammas, Nicolas, Kujath, Scott, Beasley, Robert, Vogel, Todd, Hedayati, Nasim, Brooks, James, Nelson, Peter, Parrack, Inkyong, Bernik, Thomas, Dexter, David, Brown, Kellie, Huang, Joe, Wu, Timothy, Hacker, Robert, Garland, Brandon Tyler, Griffin, Joseph, Laskowski, Igor, Pfau, Steven, Duncan, Audra, Trachtenberg, Jeffrey, Gordon, Ian, Tan, Tze-Woei, Aulivola, Bernadette, Zayed, Mohamed, Venermo, Maarit, Hill, Andrew, Wickremesekera, Janaka Kesara, Ketteler, Erika, Michelagnoli, Stefano, Bannazadeh, Mohsen, Sikalas, Nicholas, Khashram, Manar, Vasudevan, Thodur, Simmons, Justin, Osborne, Nicholas, Fox, Charles, and Vallabhaneni, Raghuveer
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- 2024
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9. Knowledge, sex, and region associated with primary care providers prescribing adolescents HIV pre-exposure prophylaxis
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Price, Garrett, Hubach, Randolph D., Currin, Joseph M., and Owens, Christopher
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- 2023
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10. The impact of initial social distancing measures on individuals' anxiety and loneliness depending on living with their romantic/sexual partners
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Currin, Joseph M., Evans, Amelia E., Miller, Bridget M., Owens, Christopher, Giano, Zachary, and Hubach, Randolph D.
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Epidemics -- Psychological aspects -- Social aspects -- United States ,Couples -- Psychological aspects -- Social aspects ,Loneliness -- Research ,Psychological research ,Anxiety -- Research ,Psychology and mental health - Abstract
In response to the COVID-19 pandemic, large swaths of the U.S. were under stay-at-home orders, thus preventing many individuals from leaving their homes. While previous studies have shown that such orders can be detrimental to mental health, specific mental health outcomes, such as loneliness and anxiety, have yet to be fully explored, particularly among various living situation contexts (e.g., living alone, with romantic/sexual partners, without romantic/sexual partners). The current study explores this using a mixed-methods approach. Data were collected via Amazon's M-Turk (N = 85). Kruskal-Wallis tests revealed significant differences between the three groups with respect to loneliness. Statistically significant greater levels of loneliness were found in individuals living alone compared to those living with romantic/sexual partners and those living with non-romantic/sexual partners. No significant differences in anxiety levels were detected. Qualitative analysis revealed similar themes among all groups regarding anxiety. When asked about loneliness, however, those living alone shared more about feeling isolated, unwanted feelings of solitude, and how technology only mitigates a portion of these feelings. Those living with others and sexual partners shared desires to see friends and co-workers, yet not to the severity described by individuals living alone. Romantic/sex life themes are also discussed., Author(s): Joseph M. Currin [sup.1] , Amelia E. Evans [sup.2] , Bridget M. Miller [sup.3] , Christopher Owens [sup.4] , Zachary Giano [sup.5] , Randolph D. Hubach [sup.6] Author Affiliations: [...]
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- 2023
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11. Motivations to Start and Stop Using Sexual Networking Applications Among Adolescent Sexual Minority Men
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Owens, Christopher, Shrodes, Addie, Kraus, Ashley, Birnholtz, Jeremy, Moskowitz, David A., and Macapagal, Kathryn
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- 2023
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12. An Exploratory Study of the PrEP Modality Preferences Among a Convenience Sample of Parents of Sexual and Gender Minority Adolescents
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Owens, Christopher, Carter, Kaileigh, Grant, Morgan J., Hubach, Randolph D., and Hoffman, Matt
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- 2023
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13. Implementation Factors Associated With Primary Care Providers' Intention to Prescribe HIV PrEP to Adolescents in the United States
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Owens, Christopher, Currin, Joseph M., Hoffman, Matt, Grant, Morgan J., and Hubach, Randolph D.
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- 2023
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14. Findings on the Monkeypox Exposure Mitigation Strategies Employed by Men Who Have Sex with Men and Transgender Women in the United States
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Hubach, Randolph D. and Owens, Christopher
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- 2022
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15. Beliefs of University Employees Leaving During a Fire Alarm: A Theory-based Belief Elicitation
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Owens, Christopher, Le, Aurora B., Smith, Todd D., and Middlestadt, Susan E.
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- 2023
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16. An economic analysis of the cost of survival of micro preemies: A systematic review
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Lee, Evelyn, Schofield, Deborah, Owens, Christopher E.L., and Oei, Ju-Lee
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- 2022
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17. “It’s Very Inconvenient for Me”: A Mixed-Method Study Assessing Barriers and Facilitators of Adolescent Sexual Minority Males Attending PrEP Follow-Up Appointments
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Owens, Christopher, Moran, Kevin, Mongrella, Melissa, Moskowitz, David A., Mustanski, Brian, and Macapagal, Kathryn
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- 2022
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18. University Student Attitudes Regarding Answering Sex, Sexual Orientation, and Gender Identity Questions on University Application Forms.
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Owens, Christopher
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COLLEGE student attitudes , *SEXUAL orientation , *STUDENT attitudes , *ATTITUDES toward sex , *UNIVERSITY & college admission , *GENDER identity - Abstract
A sample of 700 undergraduate university students throughout the US completed an online survey about their attitudes answering questions about their sex, sexual orientation, and gender identity (SSOGI) on their university admission form. This study examined differences between cisgender and transgender and gender diverse students in attitudes related to answering sex assigned at birth and gender identity questions, and between heterosexual students and students of diverse sexual orientations in attitudes related to answering sexual orientation questions. Overall, students indicated positive attitudes about answering SSOGI questions on their university application form, but attitudes toward sexual orientation questions were less positive. Differences were found in question/answer choice understanding (gender identity and sexual orientation), ease of answering (sex assigned at birth), offensiveness in asking (sex assigned at birth), privacy concerns (sex assigned at birth), comfort in answering (sex assigned at birth and sexual orientation), confidentiality concerns (gender identity), and importance of asking (sex assigned at birth and sexual orientation). Findings demonstrate that most respondents held positive attitudes about answering SSOGI questions and that communicating to LGBTQ+ applicants the importance of and privacy protections associated with answering SSOGI questions on university application forms might be important. [ABSTRACT FROM AUTHOR]
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- 2024
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19. Parent-Reported HIV Prevention Communication Topics with Sexual and Gender Minority Adolescents: A Descriptive Study.
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Grant, Morgan J., Carter, Kaileigh, Hoffman, Matt, Hubach, Randolph D., and Owens, Christopher
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SEXUAL minorities ,HIV prevention ,TEENAGERS ,SEXUAL intercourse ,SEXUAL orientation ,TEENAGE girls - Abstract
Because most parent-adolescent sex communication studies are from the perspectives of sexual and gender minority (SGM) adolescents rather than their parents, we surveyed 54 parents of SGM adolescents in the Southern region in the U.S. about their HIV-related parent-adolescent sex communication (PASC) practices. We compared topics discussed between the sexual activity and sexual orientation/gender identity of their adolescent. We found significant differences between parents having a sexually-active adolescent or not and parents discussing the importance of using condoms and what their adolescent should do if the adolescent contracts HIV. We provide future directions to further examine and improve PASC between parents and their SGM adolescents. [ABSTRACT FROM AUTHOR]
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- 2024
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20. Pharmacists’ Willingness to Provide Coronavirus Disease (COVID-19) Services and the Needs to Support COVID-19 Testing, Management, and Prevention
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Nguyen, Elaine, Owens, Christopher T., Daniels, Tayler, Boyle, Jeremy, and Robinson, Renee F.
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- 2021
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21. Patterns of Online and Offline Partnering, Partnership Characteristics, and Condomless Sex Among Adolescent Sexual Minority Males in the USA
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Macapagal, Kathryn, Moran, Kevin, Newcomb, Michael E., Moskowitz, David A., Owens, Christopher, and Mustanski, Brian
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- 2021
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22. Implementation of quantitative microbial risk assessment (QMRA) for public drinking water supplies: Systematic review
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Owens, Christopher E.L., Angles, Mark L., Cox, Peter T., Byleveld, Paul M., Osborne, Nicholas J., and Rahman, Md Bayzid
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- 2020
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23. Cytologic processing of ureteral microbiopsies is associated with higher sensitivity for detection of urothelial carcinoma compared with conventional biopsy processing
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Sheridan, Todd B., Walavalkar, Vighnesh, Yates, Jennifer K., Owens, Christopher L., and Fischer, Andrew H.
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- 2020
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24. Isotropic 3D black blood MRI of abdominal aortic aneurysm wall and intraluminal thrombus.
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Zhu, Chengcheng, Haraldsson, Henrik, Faraji, Farshid, Owens, Christopher, Gasper, Warren, Ahn, Sinyeob, Liu, Jing, Laub, Gerhard, Hope, Michael D, and Saloner, David
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Humans ,Aortic Valve Stenosis ,Aortic Aneurysm ,Abdominal ,Thrombosis ,Image Interpretation ,Computer-Assisted ,Imaging ,Three-Dimensional ,Magnetic Resonance Angiography ,Image Enhancement ,Sensitivity and Specificity ,Reproducibility of Results ,Anisotropy ,Algorithms ,Aged ,Male ,3D black blood ,Abdominal aortic aneurysm ,Blood suppression ,Intra-luminal thrombus ,Vessel wall MRI ,Rare Diseases ,Biomedical Imaging ,Clinical Research ,Cardiovascular ,Bioengineering ,Biomedical Engineering ,Clinical Sciences ,Cognitive Sciences ,Nuclear Medicine & Medical Imaging - Abstract
IntroductionThe aortic wall and intraluminal thrombus (ILT) have been increasingly studied as potential markers of progressive disease with abdominal aortic aneurysms (AAAs). Our goal was to develop a high resolution, 3D black blood MR technique for AAA wall and ILT imaging within a clinically acceptable scan time.MethodsTwenty two patients with AAAs (maximal diameter 4.3±1.0cm), along with five healthy volunteers, were imaged at 3T with a 3D T1-weighted fast-spin-echo sequence using variable flip angle trains (SPACE) with a preparation pulse (DANTE) for suppressing blood signal. Volunteers and ten patients were also scanned with SPACE alone for comparison purposes. The signal to noise ratio (SNR) and the aortic wall/ILT to lumen contrast to noise ratio (CNR) were measured. Qualitative image scores (1-4 scale) assessing the inner lumen and outer wall boundaries of AAA were performed by two blinded reviewers. In patients with ILT, the ratio of ILT signal intensity (ILTSI) over psoas muscle SI (MuscleSI) was calculated, and the signal heterogeneity of ILT was quantified as standard deviation (SD) over the mean.ResultsAll subjects were imaged successfully with an average scan time of 7.8±0.7minutes. The DANTE preparation pulse for blood suppression substantially reduced flow artifacts in SPACE with lower lumen SNR (8.8 vs. 21.4, p0.05). ILT was present in ten patients, with relatively high signal and a wide SD (average ILTSI/MuscleSI 1.42±0.48 (range 0.75-2.11)) and with SD/mean of 27.7%±6.6% (range 19.6%-39.4%).ConclusionHigh resolution, 3D black blood MRI of AAAs can be achieved in a clinical accepted scan time with reduction of flow artifacts using the DANTE preparation pulse. Signal characteristics of ILT can be quantified and may be used for improved patient-specific risk stratification.
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- 2016
25. Measurement of brachial artery endothelial function using a standard blood pressure cuff
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Maltz, Jonathan S, Tison, Geoffrey H, Alley, Hugh F, Budinger, Thomas F, Owens, Christopher D, and Olgin, Jeffrey
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Engineering ,Biomedical Engineering ,Aging ,Clinical Research ,Bioengineering ,Cardiovascular ,Adult ,Blood Pressure Determination ,Brachial Artery ,Endothelium ,Vascular ,Female ,Humans ,Male ,Middle Aged ,Reference Standards ,Signal Processing ,Computer-Assisted ,Time Factors ,Ultrasonic Waves ,Vasodilation ,endothelial function ,arterial function ,cardiovascular disease ,smooth muscle ,reactive hyperemia ,atherosclerosis ,Electrical and Electronic Engineering ,Medical Physiology ,Medical physiology ,Biomedical engineering - Abstract
The integrity of endothelial function in major arteries (EFMA) is a powerful independent predictor of heart attack and stroke. Existing ultrasound-based non-invasive assessment methods are technically challenging and suitable only for laboratory settings. EFMA, like blood pressure (BP), is both acutely and chronically affected by factors such as lifestyle and medication. Consequently, laboratory-based measurements cannot fully gauge the effects of medical interventions on EFMA. EFMA and BP have, arguably, comparable (but complementary) value in the assessment of cardiovascular health. Widespread deployment of EFMA assessment is thus a desirable clinical goal. To this end, we propose a device based on modifying the measurement protocol of a standard electronic sphygmomanometer. The protocol involves inflating the cuff to sub-diastolic levels to enable recording of the pulse waveform before and after vasodilatory stimulus. The mechanical unloading of the arterial wall provided by the cuff amplifies the distension that occurs with each pulse, which is measured as a pressure variation in the cuff. We show that the height of the rising edge of each pulse is proportional to the change in lumen area between diastole and systole. This allows the effect of vasodilatory stimuli on the artery to be measured with high sensitivity. We compare the proposed cuff flow-mediated dilation (cFMD) method to ultrasound flow-mediated dilation (uFMD). We find significant correlation (r = 0.55, p = 0.003, N = 27) between cFMD- and uFMD-based metrics obtained when the release of a 5 min cuff occlusion is employed to induce endothelial stimulus via reactive hyperemia. cFMD is approximately proportional to the square of uFMD, representing a typical increase in sensitivity to vasodilation of 300-600%. This study illustrates the potential for an individual to conveniently measure his/her EFMA by using a low-cost reprogrammed home sphygmomanometer.
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- 2015
26. Facilitators and Barriers of Pre-exposure Prophylaxis (PrEP) Uptake Among Rural Men who have Sex with Men Living in the Midwestern U.S.
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Owens, Christopher, Hubach, Randolph D., Williams, Deana, Voorheis, Eva, Lester, Jessica, Reece, Michael, and Dodge, Brian
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- 2020
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27. Vascular inflammation in a growing iliac artery aneurysm.
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Hope, Michael D, Gasper, Warren J, Rapp, Joseph, Owens, Christopher D, Haraldsson, Henrik, and Saloner, David
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Humans ,Iliac Aneurysm ,Inflammation ,Positron-Emission Tomography ,Magnetic Resonance Imaging ,Middle Aged ,Male ,Multimodal Imaging ,vascular inflammation ,aneurysm ,PET/MRI ,macrophage imaging ,Biomedical Imaging ,Bioengineering ,Cardiovascular ,Clinical Sciences ,Nuclear Medicine & Medical Imaging - Abstract
We have used a multimodality imaging approach to assess the inflammatory component of a growing iliac artery aneurysm in a 53-year-old man who presented with related ureteral obstruction. Research suggests that episodic and heterogeneous inflammatory processes are important for the progression of aneurysms. The combined PET and MRI evaluation of inflammation that we present here is a novel approach to vascular imaging that is well suited for emerging hybrid PET/MRI systems.
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- 2015
28. Ferumoxytol-enhanced magnetic resonance angiography is a feasible method for the clinical evaluation of lower extremity arterial disease.
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Walker, Joy P, Nosova, Emily, Sigovan, Monica, Rapp, Joseph, Grenon, Marlene S, Owens, Christopher D, Gasper, Warren J, and Saloner, David A
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Lower Extremity ,Kidney ,Humans ,Gadolinium DTPA ,Contrast Media ,Magnetic Resonance Angiography ,Glomerular Filtration Rate ,Risk Factors ,Prospective Studies ,Feasibility Studies ,Pilot Projects ,Predictive Value of Tests ,Aged ,Middle Aged ,San Francisco ,Male ,Renal Insufficiency ,Ferrosoferric Oxide ,Peripheral Arterial Disease ,Cardiovascular ,Biomedical Imaging ,Patient Safety ,Clinical Research ,Kidney Disease ,4.2 Evaluation of markers and technologies ,4.1 Discovery and preclinical testing of markers and technologies ,Detection ,screening and diagnosis ,Clinical Sciences ,Cardiovascular System & Hematology - Abstract
BackgroundRenal toxicity from conventional, iodinated, intravenous contrast agents is a common complication in patients with peripheral artery disease (PAD). Similarly, the potential for serious side effects prevents the use of gadolinium-based agents in many patients with depressed renal function. Ferumoxytol-enhanced magnetic resonance angiography (Fe-MRA) is a novel technique that uses an intravenous, ultrasmall, superparamagnetic, iron oxide preparation, currently approved by the Food and Drug Administration for the treatment of iron deficiency anemia in adults with chronic kidney disease. Our objective was to determine the feasibility of Fe-MRA for clinical decision making in PAD patients.MethodsThis was a prospective pilot study assessing 10 patients with suspected arterial occlusive disease with contrast-enhanced MRA of the aorta and lower extremities. Of those, 5 had renal insufficiency and were imaged with Fe-MRA, whereas the remainder underwent gadolinium-enhanced MRA. Qualitative and quantitative evaluations of deidentified images at each arterial station were independently performed by 4 blinded vascular surgeons.ResultsAll patients were men, with an average age of 68 ± 4 years. The 2 groups had similar incidences of diabetes, hypertension, hyperlipidemia, and coronary artery disease. Patients undergoing Fe-MRA had significantly decreased renal function (estimated glomerular filtration rate, 35.4 vs. 77.6; P = 0.02). There were no adverse events during contrast administration in either group. No difference was found in the overall quality of the ferumoxytol versus the gadolinium studies (7.1 ± 2.0 vs. 7.4 ± 2.4, P = 0.67). Similarly, reviewers felt comfortable basing clinical decisions on the images 89% of the time with both the ferumoxytol and gadolinium groups (P = 1.00).ConclusionsThis is the first report of an important alternative to conventional computed tomography angiography and MRA in PAD patients, particularly in the setting of renal insufficiency. Fe-MRA provides a useful tool in patients with suspected lower extremity PAD without the potential risks of gadolinium.
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- 2015
29. Vein graft failure
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Owens, Christopher D, Gasper, Warren J, Rahman, Amreen S, and Conte, Michael S
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Prevention ,Cardiovascular ,Animals ,Graft Occlusion ,Vascular ,Hemodynamics ,Humans ,Hyperplasia ,Ischemia ,Lower Extremity ,Neointima ,Risk Factors ,Stress ,Mechanical ,Time Factors ,Treatment Failure ,Vascular Grafting ,Vascular Remodeling ,Veins ,Wound Healing ,Medical and Health Sciences ,Cardiovascular System & Hematology - Abstract
After the creation of an autogenous lower extremity bypass graft, the vein must undergo a series of dynamic structural changes to stabilize the arterial hemodynamic forces. These changes, which are commonly referred to as remodeling, include an inflammatory response, the development of a neointima, matrix turnover, and cellular proliferation and apoptosis. The sum total of these processes results in dramatic alterations in the physical and biomechanical attributes of the arterialized vein. The most clinically obvious and easily measured of these is lumen remodeling of the graft. However, although somewhat less precise, wall thickness, matrix composition, and endothelial changes can be measured in vivo within the healing vein graft. Recent translational work has demonstrated the clinical relevance of remodeling as it relates to vein graft patency and the systemic factors influencing it. By correlating histologic and molecular changes in the vein, insights into potential therapeutic strategies to prevent bypass failure and areas for future investigation are explored.
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- 2015
30. Relationship between kidney disease and endothelial function in peripheral artery disease
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Chong, Karen C, Owens, Christopher D, Park, Meyeon, Alley, Hugh F, Boscardin, W John, Conte, Michael S, Gasper, Warren J, and Grenon, S Marlene
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Prevention ,Nutrition ,Aging ,Cardiovascular ,Kidney Disease ,Clinical Research ,Renal and urogenital ,Aged ,Brachial Artery ,Comorbidity ,Cross-Sectional Studies ,Endothelium ,Vascular ,Female ,Glomerular Filtration Rate ,Humans ,Intermittent Claudication ,Kidney ,Kidney Diseases ,Linear Models ,Male ,Middle Aged ,Multivariate Analysis ,Peripheral Arterial Disease ,Predictive Value of Tests ,Prognosis ,Risk Factors ,San Francisco ,Vasodilation ,Veterans Health ,Medical and Health Sciences ,Cardiovascular System & Hematology - Abstract
ObjectiveWe have previously shown that peripheral artery disease (PAD) is associated with marked impairment of endothelial function (EF). Given that poor EF is associated with functional status of PAD patients as well as with increased morbidity and mortality in patients undergoing vascular procedures, determination of factors associated with poor EF in a PAD cohort is important. We hypothesized that decreased kidney function is associated with impaired EF in patients with PAD.MethodsThis was a cross-sectional study of PAD patients presenting to a vascular surgery outpatient clinic at the San Francisco Veterans Affairs Medical Center including patients enrolled in the OMEGA-PAD I trial (NCT01310270) and the OMEGA-PAD Cohort. Brachial artery flow-mediated vasodilation was performed to assess EF. Kidney function was characterized by estimated glomerular filtration rate with the abbreviated Modification of Diet in Renal Disease formula. Linear regression was performed to assess the relationship between EF and kidney function in claudicants.ResultsNinety-seven patients with intermittent claudication participated in this study. Mean age was 69 ± 8 years, 97% were male, and 79% were white. Comorbidities included hypertension (91%), dyslipidemia (87%), coronary artery disease (42%), and diabetes mellitus (38%). Mean ankle-brachial index was 0.73 ± 0.14 and mean flow-mediated vasodilation was 7.0% ± 3.8%, indicating impaired EF. Linear regression showed an association between kidney function and EF (by 10 mL/min/1.73 m(2); β, 0.12; confidence interval, 0.05-0.20; P = .001). After multivariable regression adjusting for age, race, log tumor necrosis factor α, hypertension, dyslipidemia, and diabetes, estimated glomerular filtration rate remained significantly associated with EF (P = .033).ConclusionsIn patients with PAD, decreased kidney function is associated with endothelial dysfunction. Further longitudinal studies are needed to better understand the impact of kidney function on PAD progression and the role of endothelial dysfunction in this process.
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- 2014
31. Clinical correlates of red blood cell omega-3 fatty acid content in male veterans with peripheral arterial disease
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Nosova, Emily V, Chong, Karen C, Alley, Hugh F, Harris, William S, Boscardin, W John, Conte, Michael S, Owens, Christopher D, and Grenon, S Marlene
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Aging ,Tobacco Smoke and Health ,Clinical Research ,Heart Disease ,Complementary and Integrative Health ,Tobacco ,Prevention ,Cardiovascular ,Nutrition ,Metabolic and endocrine ,Good Health and Well Being ,Age Factors ,Aged ,Ankle Brachial Index ,Biomarkers ,Body Mass Index ,Chi-Square Distribution ,Cross-Sectional Studies ,Dietary Supplements ,Docosahexaenoic Acids ,Eicosapentaenoic Acid ,Erythrocyte Membrane ,Female ,Humans ,Linear Models ,Male ,Middle Aged ,Multivariate Analysis ,Obesity ,Peripheral Arterial Disease ,Prospective Studies ,Risk Factors ,Smoking ,Veterans Health ,Medical and Health Sciences ,Cardiovascular System & Hematology - Abstract
ObjectiveDespite available medical therapies, patients with peripheral arterial disease (PAD) remain at high risk for cardiovascular events. The n-3 polyunsaturated fatty acids (PUFA), derived from marine sources, have been shown to improve cardiovascular mortality. The Omega-3 Index (O3I), a proportion of the n-3 PUFA eicosapentaenoic acid and docosahexaenoic acid in the red blood cell membrane, correlates with cardiovascular risk. Previous investigations have found that n-3 PUFA supplementation, fish consumption, older age, and smoking history affect the O3I in different patient populations, although similar correlations have never been explored in PAD. We hypothesized that in our PAD cohort, blood content of omega-3 fatty acids would directly and positively correlate with a history of fish oil supplementation and older age and inversely correlate with a smoking history and obesity.MethodsThis cross-sectional study included 111 patients who had an ankle-brachial index of
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- 2014
32. Short-term physical inactivity impairs vascular function
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Nosova, Emily V, Yen, Priscilla, Chong, Karen C, Alley, Hugh F, Stock, Eveline O, Quinn, Alex, Hellmann, Jason, Conte, Michael S, Owens, Christopher D, Spite, Matthew, and Grenon, S Marlene
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Cardiovascular ,Clinical Research ,Heart Disease ,Prevention ,2.1 Biological and endogenous factors ,Aetiology ,Bed Rest ,Biomarkers ,Blood Pressure ,Endothelium ,Vascular ,Female ,Healthy Volunteers ,Humans ,Hydroxyeicosatetraenoic Acids ,Inflammation ,Male ,Sedentary Behavior ,Vascular Stiffness ,Young Adult ,Arterial stiffness ,Endothelial dysfunction ,Physical inactivity ,Clinical Sciences ,Surgery - Abstract
BackgroundSedentarism, also termed physical inactivity, is an independent risk factor for cardiovascular diseases. Mechanisms thought to be involved include insulin resistance, dyslipidemia, hypertension, and increased inflammation. It is unknown whether changes in vascular and endothelial function also contribute to this excess risk. We hypothesized that short-term exposure to inactivity would lead to endothelial dysfunction, arterial stiffening, and increased vascular inflammation.MethodsFive healthy subjects (four men and one woman) underwent 5 d of bed rest (BR) to simulate inactivity. Measurements of vascular function (flow-mediated vasodilation to evaluate endothelial function; applanation tonometry to assess arterial resistance), inflammation, and metabolism were made before BR, daily during BR, and 2 d after BR recovery period. Subjects maintained an isocaloric diet throughout.ResultsBR led to significant decreases in brachial artery and femoral artery flow-mediated vasodilation (brachial: 11 ± 3% pre-BR versus 9 ± 2% end-BR, P = 0.04; femoral: 4 ± 1% versus 2 ± 1%, P = 0.04). The central augmentation index increased with BR (-4 ± 9% versus 5 ± 11%, P = 0.03). Diastolic blood pressure increased (58 ± 7 mm Hg versus 62 ± 7 mm Hg, P = 0.02), whereas neither systolic blood pressure nor heart rate changed. 15-Hydroxyeicosatetraenoic acid, an arachidonic acid metabolite, increased but the other inflammatory and metabolic biomarkers were unchanged.ConclusionsOur findings show that acute exposure to sedentarism results in decreased endothelial function, arterial stiffening, increased diastolic blood pressure, and an increase in 15-hydroxyeicosatetraenoic acid. We speculate that inactivity promotes a vascular "deconditioning" state characterized by impaired endothelial function, leading to arterial stiffness and increased arterial tone. Although physiologically significant, the underlying mechanisms and clinical relevance of these findings need to be further explored.
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- 2014
33. Vitamin D deficiency is associated with mortality and adverse vascular access outcomes in patients with end-stage renal disease
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Walker, Joy P, Hiramoto, Jade S, Gasper, Warren J, Auyang, Philip, Conte, Michael S, Rapp, Joseph H, Lovett, David H, and Owens, Christopher D
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Cardiovascular ,Kidney Disease ,Clinical Research ,Prevention ,Nutrition ,Good Health and Well Being ,Age Factors ,Aged ,Aged ,80 and over ,Arteriovenous Shunt ,Surgical ,Blood Vessel Prosthesis ,Calcifediol ,Calcium ,Catheterization ,Central Venous ,Cholesterol ,Coronary Disease ,Follow-Up Studies ,Humans ,Hyperlipidemias ,Kaplan-Meier Estimate ,Kidney Failure ,Chronic ,Middle Aged ,Proportional Hazards Models ,Retrospective Studies ,Risk Factors ,Serum Albumin ,Vitamin D Deficiency ,Medical and Health Sciences ,Cardiovascular System & Hematology - Abstract
BackgroundPlasma 25 hydroxycholecalciferol (vitamin D) deficiency has been associated with adverse cardiovascular outcomes in epidemiologic studies. Chronic kidney disease is associated with loss of 1α-hydroxylase and consequently vitamin D deficiency. We hypothesized that vitamin D deficiency was associated with increased mortality and increased vascular access failure in patients undergoing permanent vascular access for end-stage renal disease.MethodsThis retrospective cohort study analyzed 128 patients undergoing permanent vascular access surgery between 2003 and 2012 for whom concurrent plasma vitamin D levels were also available. Levels were considered deficient at
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- 2014
34. Walking disability in patients with peripheral artery disease is associated with arterial endothelial function
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Grenon, S Marlene, Chong, Karen, Alley, Hugh, Nosova, Emily, Gasper, Warren, Hiramoto, Jade, Boscardin, W John, and Owens, Christopher D
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Biomedical and Clinical Sciences ,Clinical Sciences ,Clinical Research ,Atherosclerosis ,Cardiovascular ,4.2 Evaluation of markers and technologies ,Detection ,screening and diagnosis ,Aged ,Ankle Brachial Index ,Arterial Pressure ,Biomarkers ,Brachial Artery ,C-Reactive Protein ,Case-Control Studies ,Chi-Square Distribution ,Cholesterol ,HDL ,Cholesterol ,LDL ,Cross-Sectional Studies ,Disability Evaluation ,Endothelium ,Vascular ,Female ,Humans ,Intermittent Claudication ,Linear Models ,Male ,Middle Aged ,Multivariate Analysis ,Peripheral Arterial Disease ,Predictive Value of Tests ,Risk Factors ,Self Report ,Severity of Illness Index ,Vasodilation ,Walking ,Medical and Health Sciences ,Cardiovascular System & Hematology ,Cardiovascular medicine and haematology ,Clinical sciences - Abstract
ObjectivePatients with peripheral artery disease (PAD) have varying degrees of walking disability that do not completely correlate with ankle-brachial index (ABI) or angiographic anatomy. We hypothesized that endothelial function (EF) is an independent predictor of symptom severity in PAD patients.MethodsThis was a cross-sectional study of 100 PAD patients presenting to a vascular surgery clinic. All patients received ABI testing and brachial artery flow-mediated, endothelium-dependent vasodilation (FMD) to assess arterial EF. Symptom severity and walking disability reported by Rutherford category was based on the patient's self-report during the clinic visit and recorded by the investigator-vascular surgeons. Demographic, biochemical, and physiologic parameters were entered into regression equations to determine association with symptom severity.ResultsPatients were a mean age of 66 ± 8 years, and 43% had diabetes. Mean FMD was 7.4%, indicating impaired EF. EF progressively declined as Rutherford category increased (P = .01). Brachial artery FMD, ABI, systolic blood pressure, C-reactive protein, low-density lipoprotein, high-density lipoprotein, β-blocker use, and a history of diabetes or coronary artery disease were all associated with Rutherford category (all P < .05). Multivariable regression showed EF (P < .02) and ABI (P < .0001) were independently associated with walking disability. When the cohort was restricted to claudicant patients (n = 73), EF remained associated with walking disability after adjustment for other covariates (P = .0001).ConclusionsSymptom severity in PAD is multifactorial, reflecting impaired hemodynamics and vascular dysfunction. This is the first report demonstrating that walking disability in PAD is associated with arterial EF. The mechanistic link underlying these observations remains to be defined.
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- 2014
35. Safety and feasibility of adjunctive dexamethasone infusion into the adventitia of the femoropopliteal artery following endovascular revascularization
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Owens, Christopher D, Gasper, Warren J, Walker, Joy P, Alley, Hugh F, Conte, Michael S, and Grenon, S Marlene
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Cardiovascular ,Bioengineering ,Patient Safety ,Clinical Trials and Supportive Activities ,Genetics ,Atherosclerosis ,Biomedical Imaging ,Clinical Research ,6.1 Pharmaceuticals ,Evaluation of treatments and therapeutic interventions ,Adventitia ,Aged ,Angioplasty ,Balloon ,Anti-Inflammatory Agents ,Blood Flow Velocity ,Chronic Disease ,Constriction ,Pathologic ,Dexamethasone ,Female ,Femoral Artery ,Humans ,Infusions ,Intralesional ,Male ,Middle Aged ,Peripheral Arterial Disease ,Pilot Projects ,Popliteal Artery ,Prospective Studies ,Radiography ,Regional Blood Flow ,San Francisco ,Secondary Prevention ,Stents ,Time Factors ,Treatment Outcome ,Ultrasonography ,Doppler ,Duplex ,Vascular Patency ,Medical and Health Sciences ,Cardiovascular System & Hematology - Abstract
ObjectiveRestenosis following endovascular treatment of the femoropopliteal segment is associated with the inflammatory response produced in the artery wall at the time of the procedure. Although local drug delivery to the superficial femoral and popliteal arteries promises improved patency, data are currently limited. We hypothesized that improved percutaneous delivery of an anti-inflammatory compound into the adventitia of the femoropopliteal at the time of endovascular treatment would be safe, feasible, and decrease the inflammatory response.MethodsThis was a prospective, investigator-initiated, phase I, first-in-man study testing the safety and feasibility of percutaneous adventitial delivery of dexamethasone. Following successful intervention, an adventitial microinfusion catheter was advanced over a 0.014-inch wire to the treated segment. Its microneedle (0.9 mm long × 140-μm diameter) was deployed into the adventitia to deliver dexamethasone (4 mg/mL) mixed with contrast agent (80:20 ratio), providing fluoroscopic visualization. The primary safety outcome measure was freedom from vessel dissection, thrombosis, or extravasation while the primary efficacy outcome was duplex-determined binary restenosis defined as a peak systolic velocity ratio >2.5.ResultsTwenty patients with Rutherford clinical category 2-5 enrolled in this study. The mean age was 66, and 55% had diabetes mellitus. Treated lesion length was 8.9 ± 5.3 cm, and 50% were chronic total occlusions. Eighty percent of treated lesions were in the distal superficial femoral or popliteal arteries. All lesions were treated by balloon angioplasty with provisional stenting (n = 6) for suboptimal result. Three patients were treated with atherectomy as well. A mean of 1.6 ± 1.1 mg (0.5 ± 0.3 mL) of dexamethasone sodium phosphate was injected per centimeter of lesion length. In total, a mean of 12.1 ± 6.1 mg of dexamethasone was injected per patient. The mean number of injections required per lesion was 3.0 ± 1.3 cm, minimum one and maximum six injections. There was 100% technical success of drug delivery and no procedural or drug-related adverse events. The mean Rutherford score decreased from 3.1 ± .7 (median, 3.0) preoperatively to .5 ± .7 at 6 months (median, 0.0; P < .00001). Over this same time interval, the index leg ankle-brachial index increased from .68 ± .15 to .89 ± .19 (P = .0003). The preoperative C-reactive protein in this study was 6.9 ± 8.5 indicating severe baseline inflammation, which increased to 14.0 ± 23.1 mg/L (103% increase) at 24 hours following the procedure. However, this increase did not reach statistical significance of P = .14. Two patients met the primary efficacy end point of loss of primary patency by reoccluding their treated segment of the index lesion during the follow-up period.ConclusionsAdventitial drug delivery via a microinfusion catheter is a safe and feasible alternative to intimal-based methods for adjunctive treatment in the femoropopliteal segment. The 6-month preliminary results suggest perivascular dexamethasone treatment may improve outcomes following angioplasty to the femoral and popliteal arteries, and support further clinical investigation of this approach.
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- 2014
36. Adventitial Nab-Rapamycin Injection Reduces Porcine Femoral Artery Luminal Stenosis Induced by Balloon Angioplasty via Inhibition of Medial Proliferation and Adventitial Inflammation
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Gasper, Warren J, Jimenez, Cynthia A, Walker, Joy, Conte, Michael S, Seward, Kirk, and Owens, Christopher D
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Bioengineering ,Cardiovascular ,Adventitia ,Angioplasty ,Balloon ,Animals ,Arteritis ,Cell Movement ,Cell Proliferation ,Constriction ,Pathologic ,Disease Models ,Animal ,Dose-Response Relationship ,Drug ,Femoral Artery ,Fibrosis ,Injections ,Intra-Arterial ,Leukocytes ,Male ,Nanoparticles ,Sirolimus ,Swine ,Tunica Media ,coronary restenosis ,drug delivery systems ,peripheral arterial disease ,sirolimus ,Cardiorespiratory Medicine and Haematology ,Clinical Sciences ,Public Health and Health Services ,Cardiovascular System & Hematology - Abstract
BackgroundEndovascular interventions on peripheral arteries are limited by high rates of restenosis. Our hypothesis was that adventitial injection of rapamycin nanoparticles would be safe and reduce luminal stenosis in a porcine femoral artery balloon angioplasty model.Methods and resultsEighteen juvenile male crossbred swine were included. Single-injury (40%-60% femoral artery balloon overstretch injury; n=2) and double-injury models (endothelial denudation injury 2 weeks before a 20%-30% overstretch injury; n=2) were compared. The double-injury model produced significantly more luminal stenosis at 28 days, P=0.002, and no difference in medial fibrosis or inflammation. Four pigs were randomized to the double-injury model and adventitial injection of saline (n=2) or 500 μg of nanoparticle albumin-bound rapamycin (nab-rapamycin; n=2) with an endovascular microinfusion catheter. There was 100% procedural success and no difference in endothelial regeneration. At 28 days, nab-rapamycin led to significant reductions in luminal stenosis, 17% (interquartile range, 12%-35%) versus 10% (interquartile range, 8.3%-14%), P=0.001, medial cell proliferation, P
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- 2013
37. Association between n-3 polyunsaturated fatty acid content of red blood cells and inflammatory biomarkers in patients with peripheral artery disease
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Grenon, S Marlene, Conte, Michael S, Nosova, Emily, Alley, Hugh, Chong, Karen, Harris, William S, Vittinghoff, Eric, and Owens, Christopher D
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Complementary and Integrative Health ,Nutrition ,Prevention ,Cardiovascular ,Clinical Research ,Inflammatory and immune system ,Aged ,Ankle Brachial Index ,Biomarkers ,Brachial Artery ,C-Reactive Protein ,Cross-Sectional Studies ,Endothelium ,Vascular ,Erythrocytes ,Fatty Acids ,Omega-3 ,Humans ,Inflammation Mediators ,Linear Models ,Logistic Models ,Male ,Middle Aged ,Peripheral Arterial Disease ,Predictive Value of Tests ,Prognosis ,Vasodilation ,Medical and Health Sciences ,Cardiovascular System & Hematology - Abstract
ObjectiveThe n-3 polyunsaturated fatty acids are dietary components derived from fish oil with beneficial cardiovascular effects that may relate in part to anti-inflammatory properties. Peripheral artery disease (PAD) is characterized by a marked proinflammatory state. We hypothesized that the n-3 polyunsaturated fatty acids content of red blood cells (omega-3 index) would be correlated with biomarkers of inflammation and vascular function in a PAD cohort.MethodsThis was a cross-sectional study of subjects who presented to an outpatient vascular surgery clinic for evaluation of PAD. We used linear regression to evaluate the independent association between the omega-3 index, inflammatory biomarkers (C-reactive protein [CRP], intercellular adhesion molecule-1, interleukin-6, and tumor-necrosis-factor-α) and endothelial function (brachial artery flow mediated dilation).Results64 subjects (61 claudicants and three with critical limb ischemia) were recruited for the study. The mean CRP level was 5.0 ± 5.0 mg/L, and the mean omega-3 index was 5.0% ± 1.8%. In an unadjusted model, the omega-3 index was negatively associated with CRP (38% increase in CRP for one standard deviation decrease in the omega-3 index; P = .007), which remained significant after adjustment for age, body mass index, smoking, ankle-brachial index, and high-density lipoprotein (33%; P = .04). There was also evidence for independent associations between the omega-3 index and IL-6 (P = .001). There were no significant associations between the omega-3 index and vascular function tests.ConclusionsIn a cohort of patients with PAD, the omega-3 index was inversely associated with biomarkers of inflammation even after adjustment for covariates including the ankle-brachial index. Because patients with PAD have a high inflammatory burden, further studies should be conducted to determine if manipulation of omega-3 index via dietary changes or fish oil supplementation could improve inflammation and symptoms in these patients.
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- 2013
38. n-3 Polyunsaturated fatty acids supplementation in peripheral artery disease: the OMEGA-PAD trial
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Grenon, S Marlene, Owens, Christopher D, Alley, Hugh, Chong, Karen, Yen, Priscilla K, Harris, William, Hughes-Fulford, Millie, and Conte, Michael S
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Prevention ,Clinical Trials and Supportive Activities ,Clinical Research ,Cardiovascular ,Nutrition ,Complementary and Integrative Health ,Heart Disease ,Atherosclerosis ,6.1 Pharmaceuticals ,Prevention of disease and conditions ,and promotion of well-being ,3.3 Nutrition and chemoprevention ,Evaluation of treatments and therapeutic interventions ,Good Health and Well Being ,Aged ,Clinical Protocols ,Cohort Studies ,Dietary Supplements ,Double-Blind Method ,Endothelium ,Vascular ,Fatty Acids ,Omega-3 ,Female ,Humans ,Inflammation ,Male ,Middle Aged ,Peripheral Arterial Disease ,fatty acids ,peripheral artery disease ,randomized controlled trials ,Clinical Sciences ,Cardiovascular System & Hematology - Abstract
Despite current consensus guidelines recommending intensive cardiovascular risk factor management for peripheral artery disease (PAD), patients suffering from PAD continue to experience significant morbidity and mortality. This excess morbid burden is at least partially related to impaired vascular function and systemic inflammation. Interventions bridging this gap are critical. Dietary supplementation of n-3 polyunsaturated fatty acids (n-3 PUFA) has been shown to improve endothelial function and reduce inflammation in different cohorts, as well as to decrease cardiovascular events in secondary prevention trials in patients with coronary artery disease. Their effects in the PAD population are, however, less well understood. The OMEGA-PAD trial is a double-blinded, randomized, placebo-controlled trial that examines the impact of a high-dose, short-duration dietary oral supplementation of n-3 PUFA on vascular function and inflammation in patients with established PAD. The purpose of this article is to provide a detailed description of the design and methods of the OMEGA-PAD trial, and a summary of baseline characteristics of the cohort.
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- 2013
39. Peripheral artery disease and risk of cardiovascular events in patients with coronary artery disease: Insights from the Heart and Soul Study
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Grenon, S Marlene, Vittinghoff, Eric, Owens, Christopher D, Conte, Michael S, Whooley, Mary, and Cohen, Beth E
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Biomedical and Clinical Sciences ,Cardiovascular Medicine and Haematology ,Clinical Sciences ,Clinical Research ,Heart Disease ,Prevention ,Cardiovascular ,Heart Disease - Coronary Heart Disease ,Atherosclerosis ,Detection ,screening and diagnosis ,Aetiology ,4.2 Evaluation of markers and technologies ,2.1 Biological and endogenous factors ,Aged ,Biomarkers ,Coronary Artery Disease ,Disease Progression ,Female ,Humans ,Incidence ,Inflammation Mediators ,Male ,Middle Aged ,Multivariate Analysis ,Peripheral Arterial Disease ,Prognosis ,Proportional Hazards Models ,Prospective Studies ,Risk Factors ,San Francisco ,Time Factors ,coronary disease ,peripheral artery disease ,Cardiovascular System & Hematology ,Cardiovascular medicine and haematology ,Clinical sciences - Abstract
Among patients with coronary artery disease (CAD), those with peripheral artery disease (PAD) have a greater vulnerability to cardiovascular (CV) events than those with CAD alone. In a prospective cohort study of patients with CAD, we evaluated potential mechanisms that might explain the adverse CV outcomes associated with PAD. We performed a prospective cohort study of 1018 patients with stable CAD who were recruited from 2000 to 2002. Incident symptomatic PAD events were adjudicated during a follow-up period of 7.2 ± 2.6 years. We used Cox proportional hazards models to evaluate the association between incident symptomatic PAD events and subsequent risk of CV events or death. Models were adjusted for demographics, traditional risk factors, inflammation, insulin resistance and health behaviors. Among the 1018 patients, 50 patients who did not report a history of PAD at baseline suffered incident symptomatic PAD events during the follow-up period. Those patients had a higher risk of subsequent CV events and death compared to those who did not develop PAD. After adjustment for traditional risk factors, symptomatic PAD events remained associated with a 70% increased risk of subsequent CV events (adjusted HR 1.7; 95% CI 1.0, 2.9; p = 0.04) and an 80% increased risk of death (adjusted HR 1.8; 95% CI 1.2, 2.7; p = 0.006). Inflammatory biomarkers were the strongest risk factor contributing to the excess risk. In a contemporary cohort of patients with CAD, incident symptomatic PAD events were associated with an increased risk for subsequent CV events. The increased vulnerability to CV events was partially explained by shared CV risk factors and inflammation.
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- 2013
40. A single nucleotide polymorphism in the p27Kip1 gene is associated with primary patency of lower extremity vein bypass grafts
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Conte, Michael S, Owens, Christopher D, Belkin, Michael, Creager, Mark A, Edwards, Karen L, Gasper, Warren J, Kenagy, Richard D, LeBoeuf, Renee C, Sobel, Michael, and Clowes, Alexander
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Bioengineering ,Cardiovascular ,Genetics ,Clinical Research ,Aged ,Critical Illness ,Cyclin-Dependent Kinase Inhibitor p27 ,Female ,Gene Frequency ,Genetic Association Studies ,Genetic Predisposition to Disease ,Graft Occlusion ,Vascular ,Humans ,Intermittent Claudication ,Ischemia ,Lower Extremity ,Male ,Middle Aged ,Multivariate Analysis ,Peripheral Arterial Disease ,Phenotype ,Polymorphism ,Single Nucleotide ,Promoter Regions ,Genetic ,Proportional Hazards Models ,Retrospective Studies ,Risk Factors ,Time Factors ,Treatment Outcome ,Ultrasonography ,Doppler ,Duplex ,United States ,Vascular Grafting ,Vascular Patency ,Veins ,Medical and Health Sciences ,Cardiovascular System & Hematology - Abstract
ObjectiveFactors responsible for the variability in outcomes after lower extremity vein bypass grafting (LEVBG) are poorly understood. Recent evidence has suggested that a single nucleotide polymorphism (SNP) in the promoter region of the p27(Kip1) gene, a cell-cycle regulator, is associated with coronary in-stent restenosis. We hypothesized an association with vein graft patency.MethodsThis was a retrospective genetic association study nested within a prospective cohort of 204 patients from three referral centers undergoing LEVBG for claudication or critical ischemia. The main outcome measure was primary vein graft patency.ResultsAll patients were followed up for a minimum of 1 year with duplex graft surveillance (median follow-up, 893 days; interquartile range, 539-1315). Genomic DNA was isolated and SNP analysis for the p27(Kip1)-838C>A variants was performed. Allele frequencies were correlated with graft outcome using survival analysis and Cox proportional hazards modeling. The p27(Kip1)-838C>A allele frequencies observed were CA, 53%; CC, 30%; and AA, 17%, satisfying Hardy-Weinberg equilibrium. Race (P = .025) and history of coronary artery disease (P = .027) were different across the genotypes; all other baseline variables were similar. Primary graft patency was greater among patients with the -838AA genotype (75% AA vs 55% CA/CC at 3 years; P = .029). In a Cox proportional hazards model including age, sex, race, diabetes, critical limb ischemia, redo (vs primary) bypass, vein type, and baseline C-reactive protein level, the p27(Kip1)-838AA genotype was significantly associated with higher graft patency (hazard ratio for failure, 0.4; 95% confidence interval, 0.17-0.93). Genotype was also associated with early (0-1 month) changes in graft lumen diameter by ultrasound imaging.ConclusionsThese data suggest that the p27(Kip1)-838C>A SNP is associated with LEVBG patency and, together with previous reports, underscore a central role for p27(Kip1) in the generic response to vascular injury.
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- 2013
41. Vascular Remodeling in Autogenous Arterio-Venous Fistulas by MRI and CFD
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Sigovan, Monica, Rayz, Vitaliy, Gasper, Warren, Alley, Hugh F, Owens, Christopher D, and Saloner, David
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Fluid Mechanics and Thermal Engineering ,Engineering ,Biomedical Engineering ,Biomedical Imaging ,Bioengineering ,Clinical Research ,Kidney Disease ,Aged ,Aged ,80 and over ,Arm ,Arteriovenous Shunt ,Surgical ,Hemodynamics ,Humans ,Hydrodynamics ,Imaging ,Three-Dimensional ,Magnetic Resonance Angiography ,Male ,Middle Aged ,Postoperative Complications ,Renal Dialysis ,Computational fluid dynamics ,Magnetic resonance imaging ,Vascular access ,Hemodialysis fistula ,Vascular remodeling ,WSS - Abstract
Hemodynamic parameters play an important role in regulating vascular remodeling in arterio-venous fistula (AVF) maturation. Investigating the changes in hemodynamic parameters during AVF maturation is expected to improve our understanding of fistula failure, but very little data on actual temporal changes in human AVFs is available. The present study aimed to assess the feasibility of using a noncontrast-enhanced MRI protocol combined with CFD modeling to relate hemodynamic changes to vascular remodeling following native AVF placement. MR angiography (MRA) and MR velocimetry (MRV) data was acquired peri-operatively, 1 month, and 3 months later in three patients. Vascular geometries were obtained by segmentation of the MRA images. Pulsatile flow simulations were performed in the patient specific vascular geometries with time-dependent boundary conditions prescribed from MRV measurements. A principal result of the study is the description of WSS changes over time in the same patients. The disturbed flow observed in the venous segments resulted in a variability of the WSS distribution and could be responsible for the non-uniform remodeling of the vessel. The artery did not show regions of disturbed flow upstream from the anastomosis, which would be consistent with the uniform remodeling. MRI use demonstrated the ability to provide a comprehensive evaluation of clinically relevant information for the investigation of upper extremity AVFs. 3D geometry from MRA in combination with MRV provides the opportunity to perform detailed CFD analysis of local hemodynamics in order to determine flow descriptors affecting fistula maturation.
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- 2013
42. Thirty-day vein remodeling is predictive of midterm graft patency after lower extremity bypass
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Gasper, Warren J, Owens, Christopher D, Kim, Ji Min, Hills, Nancy, Belkin, Michael, Creager, Mark A, and Conte, Michael S
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Clinical Research ,Cardiovascular ,Aged ,Biomarkers ,Boston ,C-Reactive Protein ,Female ,Genetic Testing ,Graft Occlusion ,Vascular ,Humans ,Inflammation Mediators ,Kaplan-Meier Estimate ,Linear Models ,Longitudinal Studies ,Lower Extremity ,Male ,Middle Aged ,Multivariate Analysis ,Peripheral Arterial Disease ,Proportional Hazards Models ,Prospective Studies ,Time Factors ,Treatment Outcome ,Ultrasonography ,Doppler ,Duplex ,Vascular Patency ,Veins ,Medical and Health Sciences ,Cardiovascular System & Hematology - Abstract
ObjectiveSuccessful adaptation of a vein graft to an arterial environment is incompletely understood. We sought to investigate whether early vein graft remodeling is predictive of subsequent patency.MethodsA prospective longitudinal study was conducted of 67 patients undergoing lower extremity bypass with autogenous vein between February 2004 and April 2008. Preoperative blood samples were drawn for biomarkers. During the bypass operation, a 5-cm index segment of the graft was registered for serial lumen diameter measurements at 0, 1, 3, 6, 9, and 12 months using duplex ultrasound imaging. The imaging substudy analysis included patients with at least two ultrasound assessments.ResultsPatients (55% male) were a median age of 70 years (interquartile range [IQR], 59-76 years), 40% had diabetes mellitus, 49% had critical limb ischemia, 75% were taking a statin, and 91% were taking an antiplatelet medication. Median follow-up was 32 months (IQR, 15-47 months). The median baseline high-sensitivity C-reactive protein level (hsCRP) was 3.2 mg/L (IQR, 1.4-9.7 mg/L). The average intraoperative, postimplantation vein lumen diameter was 3.9±1.0 mm, increasing to 4.7±1.1 mm at 1 month, an average 24%±27% change per patient. By 3 months, the average lumen diameter was 5.1±1.6 mm, with little subsequent change observed to 12 months. Nonwhite race, baseline hsCRP ≥5 mg/L, statin use, and initial lumen diameter were significantly associated with early (0- to 1-month) vein remodeling in a multivariable regression model. The primary patency rate for the cohort was 60%±6.3% at 2 years. Initial lumen diameter of the index segment was not associated with primary patency, whereas larger lumen diameter achieved at 1 month (≥5.1 mm) was positively associated with primary patency (log-rank, P=.03). Early (30-day) remodeling behavior was used to divide patients into "poor remodelers" (+25% change, n=30). Early remodeling category was significantly associated with primary patency rate at 2 years (log-rank, P=.02). A multivariable Cox proportional hazards model showed that modest remodelers (hazard ratio, 3.9; 95% confidence interval, 1.02-15; P=.04) and poor remodelers (hazard ratio, 13; 95% confidence interval; P=.008) had significantly higher hazard ratios for graft failure than robust early remodelers.ConclusionsEarly remodeling of the arterialized vein appears to predict midterm bypass graft patency. In addition to baseline diameter, race, inflammation, hsCRP, and statin use are associated with early adaptive remodeling, but the mechanisms for these observations are not understood.
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- 2013
43. Relationships Among Sexual Identity, Sexual Attraction, and Sexual Behavior: Results from a Nationally Representative Probability Sample of Adults in the United States
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Fu, Tsung-chieh, Herbenick, Debby, Dodge, Brian, Owens, Christopher, Sanders, Stephanie A., Reece, Michael, and Fortenberry, J. Dennis
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- 2019
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44. High-density linkage maps and loci for berry color and flower sex in muscadine grape (Vitis rotundifolia)
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Lewter, Jennifer, Worthington, Margaret L., Clark, John R., Varanasi, Aruna V., Nelson, Lacy, Owens, Christopher L., Conner, Patrick, and Gunawan, Gunawati
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- 2019
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45. USPIO-enhanced MR Angiography of Arteriovenous Fistulas in Patients with Renal Failure
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Sigovan, Monica, Gasper, Warren, Alley, Hugh F, Owens, Christopher D, and Saloner, David
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Biomedical and Clinical Sciences ,Clinical Sciences ,Clinical Research ,Biomedical Imaging ,Kidney Disease ,Anastomosis ,Surgical ,Arteriovenous Anastomosis ,Contrast Media ,Dextrans ,Female ,Humans ,Image Enhancement ,Magnetic Resonance Angiography ,Magnetite Nanoparticles ,Male ,Renal Insufficiency ,Reproducibility of Results ,Sensitivity and Specificity ,Medical and Health Sciences ,Nuclear Medicine & Medical Imaging ,Clinical sciences - Abstract
PurposeTo determine the feasibility of using ferumoxytol-enhanced magnetic resonance (MR) angiography to depict the vasculature of hemodialysis fistulas and improve image quality compared with nonenhanced time-of-flight (TOF) MR angiography.Materials and methodsThe study was institutional review board approved and was in compliance with HIPAA regulations. All participants provided written informed consent. TOF and first-pass ferumoxytol-enhanced MR angiography were performed in 10 patients with upper extremity autogenous fistulas. Ferumoxytol was administered as a bolus solution containing 430 μmol of elemental iron. A qualitative comparison was performed on maximum intensity projection images. Lumen depiction was evaluated by using a five-point scale. The uniformity of intraluminal signal intensity was measured as the ratio between the mean signal intensity of the entirety of the imaged fistula and its standard deviation. The contrast-to-noise ratio (CNR) between intraluminal signal and adjacent tissue was evaluated as a function of image acquisition time. Lumen depiction scores, luminal signal heterogeneity, and CNR efficiency were compared between TOF and ferumoxytol-enhanced MR angiography by using a Wilcoxon-Mann-Whitney test.ResultsFlow artifacts were greatly reduced by the use of ferumoxytol-enhanced MR angiography. Ferumoxytol-enhanced MR angiography had significantly better performance than TOF MR angiography as measured with the following: lumen depiction scores in all segments (mean, 4.7±0.1 [standard error of the mean]; vs 3.0±0.3 for arterial inflow, 4.1±0.3 vs 1.9±0.3 for arterial outflow, 3.7±0.3 vs 1.8±0.2 for anastomosis, and 4.5±0.2 vs 2.1±0.2 for venous outflow; P
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- 2012
46. “Corps” leadership: a cadet perspective on shared leadership
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Martin, Ira H., Prophet, Trevor, Owens, Christopher, Martin, JennyMae, and Plummer, Gabe
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- 2017
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47. Sex-based differences in the inflammatory profile of peripheral artery disease and the association with primary patency of lower extremity vein bypass grafts
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Hiramoto, Jade S, Owens, Christopher D, Kim, Ji Min, Boscardin, John, Belkin, Michael, Creager, Mark A, and Conte, Michael S
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Cardiovascular ,Clinical Research ,Heart Disease ,Aged ,C-Reactive Protein ,Female ,Fibrinogen ,Humans ,Male ,Middle Aged ,Multivariate Analysis ,Peripheral Arterial Disease ,Proportional Hazards Models ,Prospective Studies ,Sex Factors ,Vascular Patency ,Vascular Surgical Procedures ,Medical and Health Sciences ,Cardiovascular System & Hematology - Abstract
ObjectiveThis study was conducted to determine if there are sex-based differences in the inflammatory phenotype of patients undergoing lower extremity bypass (LEB) and if they correlate with clinical outcomes.MethodsThis was a retrospective analysis of a prospective cohort of 225 patients (161 men and 64 women) who underwent autogenous vein LEB between February 2004 and May 2008. Fasting baseline blood samples were obtained before LEB, and the inflammatory biomarkers high-sensitivity C-reactive protein (CRP) and fibrinogen were assessed. All patients underwent ultrasound graft surveillance. CRP levels were dichotomized at 5 mg/L and fibrinogen levels at 600 mg/dL.ResultsThere were no significant differences in age, race, history of hypertension or diabetes mellitus, body mass index, or coronary artery disease between men and women. Men were more likely to be current smokers (P = .02), have a history of hypercholesterolemia (P = .02), and be taking statins (P = .02). Women were more likely to present with critical limb ischemia (P = .03) and had higher median baseline CRP levels (5.15 mg/L; interquartile range [IQR], 1.51-18.62 mg/L) than men (2.70; IQR, 1.24-6.98 mg/L; P = .02). Median follow-up was 893 days (IQR, 539-1315 days). A multivariable Cox proportional hazards model for primary vein graft patency showed a significant interaction between sex and CRP (P = .03) and fibrinogen (P = .02). After adjustment for key covariates, primary vein graft patency was significantly less in women with CRP >5 mg/L compared with women with CRP 600 mg/dL vs women with fibrinogen
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- 2012
48. Primary Care Providers' Information Needs for Prescribing Adolescents HIV Pre-Exposure Prophylaxis.
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Owens, Christopher, Stukenberg, Jacob, Grant, Morgan J., and Hoffman, Matt
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HIV prevention , *PROFESSIONS , *RESEARCH methodology , *ANTIVIRAL agents , *PRE-exposure prophylaxis , *COMPARATIVE studies , *DRUG prescribing , *DESCRIPTIVE statistics , *CHI-squared test , *INFORMATION needs , *MEDICAL prescriptions , *PHYSICIAN practice patterns , *CONTENT analysis , *THEMATIC analysis , *DATA analysis software , *ADOLESCENCE - Abstract
Although knowledge is a salient determinant in primary care providers (PCPs) prescribing HIV pre-exposure prophylaxis (PrEP) to adolescents, we know little about what information PCPs want about PrEP. We conducted an online mixed-method study to explore the PrEP information needs of a national sample of 351 PCPs. We analyzed data with deductive content analysis and compared themes between respondents who were aware and not aware of PrEP, knowledgeable and not knowledgeable of the prescribing guidelines, and prescribed and never prescribed PrEP to an adolescent. PCPs who were unknowledgeable about PrEP and never prescribed PrEP to an adolescent mentioned manufacturing information, indications and dosing, and contraindications and adverse reactions more so than PCPs who were aware of and prescribed PrEP. A better understanding of the information needs of PCPs could inform provider education interventions. Future research must examine the facilitators and barriers to integrating PrEP information into medical education and clinical settings. [ABSTRACT FROM AUTHOR]
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- 2023
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49. Implementation Facilitators and Barriers for Primary Care Providers Prescribing Daily Oral PrEP to Adolescents in the United States.
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Owens, Christopher, Gray, Samuel J., Carter, Kaileigh, Hoffman, Matt, Mullen, Cody, and Hubach, Randolph D.
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HIV prevention , *ANTI-HIV agents , *PILOT projects , *HEALTH services accessibility , *ORAL drug administration , *CROSS-sectional method , *ATTITUDES of medical personnel , *FAMILY medicine , *ACQUISITION of data , *FISHER exact test , *PRE-exposure prophylaxis , *COMPARATIVE studies , *PRIMARY health care , *DRUGS , *DRUG prescribing , *QUESTIONNAIRES , *MEDICAL records , *CHI-squared test , *DESCRIPTIVE statistics , *PHYSICIAN practice patterns , *CONTENT analysis , *ADOLESCENCE - Abstract
Primary care providers (PCPs) are critical in prescribing human immunodeficiency virus (HIV) pre-exposure prophylaxis (PrEP) to adolescents at risk of HIV. More research is needed to identify facilitators and barriers PCPs encounter in prescribing PrEP to eligible adolescents post-Food and Drug Administration (FDA) approval. This online cross-sectional survey examined the PrEP implementation facilitators and barriers among a national sample of PCPs in the United States. PCPs (n = 502) specializing in family medicine or pediatrics were recruited from a Qualtrics panel from July 15 to August 9, 2022. We analyzed the collected data using content analysis and applied the Expert Recommendations for Implementing Change (ERIC) to codebook creation and data analysis. We conducted a Fisher's exact chi-square test of independence to compare facilitator and barrier prevalence differences between participants who had and had not prescribed PrEP to an adolescent patient. Results demonstrate that (1) distributing prescriber-focused educational materials, (2) involving parents, (3) changing liability laws, (4) enhancing adolescent PrEP uptake and adherence, (5) changing clinical resources, and (6) using mass/social media to change community norms might be strategies that influence PCPs prescribing PrEP to eligible adolescent patients. Results from this study could facilitate the planning of hybrid implementation-effectiveness trials designed to determine the acceptability, feasibility, and effectiveness of implementation strategies in improving the practices of PCPs prescribing PrEP to at-risk adolescents. [ABSTRACT FROM AUTHOR]
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- 2023
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50. An Exploratory Study of the Mpox Media Consumption, Attitudes, and Preferences of Sexual and Gender Minority People Assigned Male at Birth in the United States.
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Owens, Christopher and Hubach, Randolph D.
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- 2023
- Full Text
- View/download PDF
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