Showing papers by "Keith M. Sullivan published in 2003"

Polymyositis as a manifestation of chronic graft‐versus‐host disease

Abstract: Objective Chronic graft-versus-host disease (GVHD) after haematopoietic stem cell transplantation (HSCT) has similarities to some idiopathic autoimmune diseases, including polymyositis. To investigate the relationship between chronic GVHD and idiopathic myositis we conducted a detailed analysis of all cases of myositis occurring in a large series of HSCT patients. Methods We conducted a retrospective chart review of all cases of myositis that developed in 7161 patients who underwent HSCT at the Fred Hutchinson Cancer Research Center between 1969 and 1999. Results Among 1859 individuals who developed chronic GVHD, 12 developed myositis. No patients developed myositis without chronic GVHD. Myositis was first identified between 7 and 55 months after transplantation. In histopathology, electromyography, laboratory values and response to immunosuppressive therapy, the cases resembled idiopathic polymyositis. Autoantibodies were found in eight cases. Conclusions Myositis in the chronic GVHD population occurred with an incidence higher than expected by chance, suggesting that muscle may be a target tissue for chronic GVHD. Recent studies have implicated allogeneic cells persisting after maternal-fetal cell transfer in selected autoimmune diseases, including myositis. This report lends support to the possibility that both idiopathic myositis and chronic GVHD-related myositis could involve allo-autoimmune responses.

Incidence, risk factors, and mortality from pneumonia developing late after hematopoietic stem cell transplantation.

Abstract: The incidence, etiology, outcome, and risk factors for developing pneumonia late after hematopoietic stem cell transplantation (SCT) were investigated in 1359 patients transplanted in Seattle. A total of 341 patients (25% of the cohort) developed at least one pneumonic episode. No microbial or tissue diagnosis (ie clinical pneumonia) was established in 197 patients (58% of first pneumonia cases). Among the remaining 144 patients, established etiologies included 33 viral (10%), 31 bacterial (9%), 25 idiopathic pneumonia syndrome (IPS, 7%), 20 multiple organisms (6%), 19 fungal (6%), and 16 Pneumocystis carinii pneumonia (PCP) (5%). The overall cumulative incidence of first pneumonia at 4 years after discharge home was 31%. The cumulative incidences of pneumonia according to donor type at 1 and 4 years after discharge home were 13 and 18% (autologous/syngeneic), 22 and 34% (HLA-matched related), and 26 and 39% (mismatched related/unrelated), respectively. Multivariate analysis of factors associated with development of late pneumonia after allografting were increasing patient age (RR 0.5 for 40 years, P=0.009), donor HLA-mismatch (RR 1.6 for unrelated/mismatched related, P=0.01), and chronic graft-versus-host disease (GVHD; RR 1.5, P=0.007). Our data suggest that extension of PCP prophylaxis may be beneficial in high-risk autograft recipients. Further study of long-term anti-infective prophylaxis based on patient risk factors after SCT appear warranted.

Case Based Reasoning for Medical Decision-Support in a Safety Critical Environment

Abstract: Case-based reasoning systems applied to safety-critical environments justify specific measures to ensure that the assistance provided is not dangerous to human life. This article presents a case-based reasoning system developed for medical decision-support in a safety-critical environment, the CARE- PARTNER system. Based on the evaluation of the reliability of the system, it stresses the importance to differentiate between reliability and safety, and how case-based reasoning can ensure safety. A knowledge-based approach has enabled to model what types of information are safety-critical, and to adapt the decision-support system results, by introspective reasoning, based on the knowledge type, the user, and the task.

The Analysis of Network Centric Maritime Interdiction Operations (MIO) Using Queueing Theory

Abstract: : In 2001 the Maritime Systems Group of The Technical Cooperation Program (TTCP) set-up an Action Group (AG-1) to examine the exponential increases in warfighting capability claimed for Network-Centric Maritime Warfare (NCMW). Analysis of NCMW is a two-stage process of finding analysis processes for estimating the NCMW effects on the scenario parameters and then applying appropriate warfare models to relate NCMW-sensitive scenario parameters to force effectiveness. This paper will report on the results of a modeling workshop held by AG-1 in November 2002. The workshop's focus was to investigate the usefulness of applying a queueing model to Maritime Interdiction Operations (MIO) within the context of the NCMW concept of tactical collaborative planning. Both analytical and simulation-based queueing models were examined, and the theoretical model was applied parametrically to two MIO scenarios. Using the steady-state probability of target vessel interdiction (i.e., service) as the primary measure of effectiveness, the workshop was able to demonstrate the usefulness of queueing to relate NCMW application measures to force effectiveness. In addition, the queueing models provided valuable insight into the aspects of the MIO task where NCMW concepts might be applied. Thus, queueing is directly applicable to the second stage of analysis for operations that can be viewed as a demand for service, and provides direction in the process of refining NCMW concepts into testable applications. The parametric results from the workshop provide general bounds on expected improvements in effectiveness; however, specific results will depend upon the particular NCMW applications and how they are used.

QSIM: A Queueing Theory Model with Various Probability Distribution Functions

Abstract: : QSIM is a queueing theory model developed to interpret the various undertakings involved in military operations The multiple probability distribution functions (PDFs) for arrival, service, and renege rates not only allow QSIM to analyze a variety of specific warfare tasks (especially those characterized by nonexponential PDFs), but they also ensure that the model is applicable to many other situations Moreover, the relatively efficient run times permit the user to analyze a range of input values quickly

A Proposed Framework for Network-Centric Maritime Warfare Analysis

Abstract: : The benefits of network-centric warfare are addressed in many publications, but few of these publications actually demonstrate how to quantify these alleged benefits. This report proposes an analytical framework to quantify the value-added of network-centric warfare; that framework is queueing theory, which is based on the concept of a demand-for-service process. Most warfare tasks can be characterized as demand-for-service processes. This report shows how queueing theory can be applied to demand-for-service warfare tasks and thus provide the basis for analyzing and quantifying those tasks. In addition, this report demonstrates how the functions of many of the independent and dependent variables and associated warfare metrics can be translated into the characteristics and metrics of queues.