Axonal conduction deficit is a major contributor to various degrees of disability after spinal cord injury. 4-aminopyridine (4-AP), a potassium channel blocker, has been shown to restore some conduction and improve neurological function in both animal and human studies. Using a double sucrose-gap recording device, we have examined the effects of 4-AP on isolated guinea pig spinal cord white matter after stretch injury. At a concentration of 100 microM, 4-AP increased the amplitude of the compound action potential by 100% while 1 microM 4-AP increased it by 43%, a larger response than seen following compression injury. The length of affected tissue is suggested as a potential explanation of this differential sensitivity to 4-AP. Plastic sections taken from the injury site revealed severe myelin damage, especially in the paranodal area, which may also partially explain why 4-AP has more effect on conduction after stretch injury than compression. In addition, we have shown that while enhancing conductivity in some axons, 4-AP significantly reduced the overall responsiveness to multiple stimuli, as evidenced by increase of the refractory period in response to dual stimuli and the decreased ability to follow repetitive stimuli. This increased refractoriness may be largely attributed to residual deficits in fibers newly recruited by 4-AP treatment.
This article serves three purposes. First, we present a new source of campaign finance data for the 50 states. This includes annual data on candidate expenditures in gubernatorial races from 1977 to 2001, as well as triennial and biennial data on campaign finance laws affecting gubernatorial races during this period. Second, we review the various sources of campaign finance data for the 50 states. Third, we examine the challenges of collecting and compiling data across the 50 states, since these data can vary so much in availability and measurement. We hope to provide some general lessons to researchers collecting or working with all types of cross-state data.
The intersection of gender-and to a lesser extent, race-and political ambition has been the subject of considerable research. To date, however, analyses of the intersection of political ambition, race, and gender in the context of the judiciary have been limited. The authors seek to remedy this deficiency with the use of data from a recent survey of justices of the New York State Supreme Court, the major trial court in the State of New York. They find that female and nonwhite justices have a greater desire to move up in a judicial career than do their white male counterparts.
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