Browsing by Subject "instability"

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    Poleward Transport of TPX2 in the Mammalian Mitotic Spindle Requires Dynein, Eg5, and Microtubule Flux
    (2010) Ma, Nan; Tulu, US; Ferenz, Nick P; Fagerstrom, Carey; Wilde, Andrew; Wadsworth, Patricia
    TPX2 is a Ran-regulated spindle assembly factor that is required for kinetochore fiber formation and activation of the mitotic kinase Aurora A. TPX2 is enriched near spindle poles and is required near kinetochores, suggesting that it undergoes dynamic relocalization throughout mitosis. Using photoactivation, we measured the movement of PA-GFP-TPX2 in the mitotic spindle. TPX2 moves poleward in the half-spindle and is static in the interzone and near spindle poles. Poleward transport of TPX2 is sensitive to inhibition of dynein or Eg5 and to suppression of microtubule flux with nocodazole or antibodies to Kif2a. Poleward transport requires the C terminus of TPX2, a domain that interacts with Eg5. Overexpression of TPX2 lacking this domain induced excessive microtubule formation near kinetochores, defects in spindle assembly and blocked mitotic progression. Our data support a model in which poleward transport of TPX2 down-regulates its microtubule nucleating activity near kinetochores and links microtubules generated at kinetochores to dynein for incorporation into the spindle.
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    The Concept of Instability and the Theory of Democracy in the Federalist
    (2008-04-18) Furlow Sauls, Shanaysha M
    This dissertation describes instability as a problem with a variety of sources and explains Publius' contribution to understanding the importance of these problems for politics and political theory. Using the Federalist and Publius' reading in political theory, history, and politics to ground my analysis, I explain the concept of instability as a multi-faceted problem that requires different solutions. I show that instability arises from one or a combination of four distinct notions: stasis or factional conflict, corruption, the mutability of the laws, and changing global conditions. My dissertation suggests that one of the primary goals of ancient and modern democracies was to solve the political challenges posed by instability. I further argue that the sources of instability remain relevant because they allow us to describe the problem of instability in a way that is theoretically and practically useful for understanding the role that democracy plays in addressing them. Finally, I suggest that describing and addressing the patterns of instability were central to Publius' interpretation of history and political theory and that recognizing and tackling these patterns are a part of the scope of modern political science and are central to the study of democratic politics.
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    Understanding Preferences for Treatment After Hypothetical First-Time Anterior Shoulder Dislocation: Surveying an Online Panel Utilizing a Novel Shared Decision-Making Tool.
    (Orthop J Sports Med, 2017-03) Streufert, Ben; Reed, Shelby D; Orlando, Lori A; Taylor, Dean C; Huber, Joel C; Mather, Richard C
    BACKGROUND: Although surgical management of a first-time anterior shoulder dislocation (FTASD) can reduce the risk of recurrent dislocation, other treatment characteristics, costs, and outcomes are important to patients considering treatment options. While patient preferences, such as those elicited by conjoint analysis, have been shown to be important in medical decision-making, the magnitudes or effects of patient preferences in treating an FTASD are unknown. PURPOSE: To test a novel shared decision-making tool after sustained FTASD. Specifically measured were the following: (1) importance of aspects of operative versus nonoperative treatment, (2) respondents' agreement with results generated by the tool, (3) willingness to share these results with physicians, and (4) association of results with choice of treatment after FTASD. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: A tool was designed and tested using members of Amazon Mechanical Turk, an online panel. The tool included an adaptive conjoint analysis exercise, a method to understand individuals' perceived importance of the following attributes of treatment: (1) chance of recurrent dislocation, (2) cost, (3) short-term limits on shoulder motion, (4) limits on participation in high-risk activities, and (5) duration of physical therapy. Respondents then chose between operative and nonoperative treatment for hypothetical shoulder dislocation. RESULTS: Overall, 374 of 501 (75%) respondents met the inclusion criteria, of which most were young, active males; one-third reported prior dislocation. From the conjoint analysis, the importance of recurrent dislocation and cost of treatment were the most important attributes. A substantial majority agreed with the tool's ability to generate representative preferences and indicated that they would share these preferences with their physician. Importance of recurrence proved significantly predictive of respondents' treatment choices, independent of sex or age; however, activity level was important to previous dislocators. A total of 125 (55%) males and 33 (23%) females chose surgery after FTASD, as did 37% of previous dislocators compared with 45% of nondislocators. CONCLUSION: When given thorough information about the risks and benefits, respondents had strong preferences for operative treatment after an FTASD. Respondents agreed with the survey results and wanted to share the information with providers. Recurrence was the most important attribute and played a role in decisions about treatment.