Modifiable Barriers to Optimal Outcomes in Gout Management

Improving patient outcomes in chronic disease is of critical importance to the future of health care. Gout, affecting 4% of the US population, is a highly treatable chronic disease from which patients experience unnecessarily suboptimal outcomes. In this dissertation, I demonstrate how interrelated patient and provider factors affect patient outcomes in gout. First, I describe how only 14% of gout patients know their serum urate (SU) goal for urate lowering therapy (ULT) despite otherwise being knowledgeable about gout and its treatment. I then demonstrate the importance of multiple patient and provider factors in achieving SU goal. Specifically, I demonstrate that ULT medication adherence, ULT dose escalation and a high ULT starting dose are associated with SU goal attainment. However, I show that a high starting dose is also associated with worse SU goal attainment through its negative impact on medication adherence. These findings demonstrate not only the importance of patient and provider behaviors in achieving optimal outcomes, but also their interrelated nature. Finally, I report that there is no evidence from a large national study that ULT dose escalation reduces mortality among gout patients. In further analysis, I demonstrate that the lack of evidence could be due to inadequate final ULT doses observed even among patients receiving dose escalation. Importantly, the patient and provider factors I identify in this work are all modifiable. Future interventions should address the broad care context outlined in the Chronic Care Model to target these interrelated, modifiable factors and achieve optimal outcomes in gout

A computer operated mass spectrometer system

Digital computer system for processing mass spectrometer output dat

Computer control of mass analyzers

Digital computer control of mass spectrometer

Multiple Cyclotron Lines in the Spectrum of 4U 0115+63

We report phase resolved spectroscopy of the transient accreting pulsar, 4U0115+63. For the first time, more than two cylotron resonance scattering features are detected in the spectrum of an X-ray pulsar. The shape of the fundamental line appears to be complex, and this is in agreement with predictions of Monte-Carlo models. As in other pulsars, the line energies and optical depths are strong functions of pulse phase. One possible model for this is an offset of the dipole of the neutron star magnetic field.Comment: 5 pages. To appear in "Proceedings of the 5th Compton Symposium

New direction for gamma-rays

The origin of energetic gamma-ray bursts is still unknown. But the detection of polarization of gamma-rays provides fresh insight into the mechanism driving these powerful explosions.Comment: Nature "News & Views", RE Coburn & Boggs (astro-ph/0305377

Discovery of a Cyclotron Resonance Scattering Feature in the X-ray Spectrum of XTE J1946+274

Observations of the transient accreting pulsar XTE J1946+274 made with the Rossi X-ray Timing Explorer during the course of the 1998 September-November outburst, reveal a cyclotron resonance scattering feature (or "cyclotron line") in the hard X-ray spectrum near 35 keV. We determine a centroid energy of 36.2 +0.5/-0.7 keV, which implies a magnetic field strength of 3.1(1+z)x10^12 G, where z is the gravitational redshift of the scattering region. The optical depth, Tau = 0.33 +0.07/-0.06, and width, sigma = 3.37 +0.92/-0.75 keV, are typical of known cyclotron lines in other pulsars. This discovery makes XTE J1946+274 one of thirteen pulsars with securely detected cyclotron lines resulting in direct magnetic field measurements.Comment: Five pages including four postscript figures and two tables. Uses emulateapj5. Published in ApJ Letters: http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2001ApJ...563L..35

Discovery of a flux-related change of the cyclotron line energy in Her X-1

We present the results of ten years of repeated measurements of the Cyclotron Resonance Scattering Feature (CRSF) in the spectrum of the binary X-ray pulsar Her X-1 and report the discovery of a positive correlation of the centroid energy of this absorption feature in pulse phase averaged spectra with source luminosity.Our results are based on a uniform analysis of observations bythe RXTE satellite from 1996 to 2005, using sufficiently long observations of 12 individual 35-day Main-On states of the source. The mean centroid energy E_c of the CRSF in pulse phase averaged spectra of Her X-1 during this time is around 40 keV, with significant variations from one Main-On state to the next. We find that the centroid energy of the CRSF in Her X-1 changes by ~5% in energy for a factor of 2 in luminosity. The correlation is positive, contrary to what is observed in some high luminosity transient pulsars. Our finding is the first significant measurement of a positive correlation between E_c and luminosity in any X-ray pulsar. We suggest that this behaviour is expected in the case of sub-Eddington accretion and present a calculation of a quantitative estimate, which is very consistent with the effect observed in Her X-1.We urge that Her X-1 is regularly monitored further and that other X-ray pulsars are investigated for a similar behaviour.Comment: 4 pages, 2 figures, accepted by A&A Letter