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Biomedical subjects

W W Stead

Publications and source records attributed to W W Stead.

At least 19 recordsLinked to original sources
PubMed2004

Persistence of a strain of Mycobacterium tuberculosis in a prison system.

SETTING: A prison system with an average year-end census of 9084 inmates. OBJECTIVE: To determine transmission dynamics of tuberculosis over a long period; to establish whether Mycobacterium tuberculosis strains responsible for disease in a prison system persist; and to determine whether patients in a community whose isolates cluster with those in a prison system are linked. DESIGN: Retrospective epidemiologic analysis was performed on tuberculosis cases reported in a prison system over a 9-year period. In addition, IS6110 RFLP patterns of M. tuberculosis isolates obtained from prisoners were compared with those of other cases from the state at large. The results of the RFLP analysis and the epidemiologic investigation were compared. RESULTS: Approximately 80% of tuberculosis cases in the prison system were clustered. Over 9 years, a single strain of M. tuberculosis accounted for more than 50% of cases. Patients from the community at large who were infected with the same strain were linked to the prison system. CONCLUSION: In spite of intensive tuberculosis control efforts, a single strain of M. tuberculosis has persisted in the prison system. Its persistence is accounted for by activation of latent infection in patients who, prior to being diagnosed and treated, infected other patients, who then sustained the transmission chain.

Adult↗
PubMed2001

Variation in vulnerability to tuberculosis in America today: random, or legacies of different ancestral epidemics?

OBJECTIVE: To test the hypothesis that vulnerability to infection by Mycobacterium tuberculosis is the norm for mankind but innate resistance to the infection is common in the USA today as a legacy of TB epidemics survived by one's ancestors. MEASUREMENTS: A reaction of 10 mm or more to a tuberculin skin test (TST) was used to determine the prevalence of infection following community outbreaks of the disease. For further information, a survey was conducted of prevalence of tuberculin reactivity among health-care workers with frequent exposures to tuberculosis patients during bronchoscopy and sputum collection. RESULTS: Sixty per cent of African Americans exposed in 26 community outbreaks were TST positive compared to only 40% of whites following comparable exposures. Similarly only 56 (41.2%) of 136 heavily exposed white health-care workers were TST positive. CONCLUSIONS: When considered in conjunction with contrasting ancestral histories of exposure to TB, these observations suggest a difference in frequency of an innate ability to respond protectively to M. tuberculosis and to mount an effective mechanism to destroy it. This is best explained as a process of natural selection among largely separate heavily exposed ancestors. Several recent reports have identified genetically mediated mechanisms of immunity that could be involved with reduced vulnerability to tuberculosis. An understanding of these processes could aid in the development of immunomodulatory agents or vaccines.

Black People↗
PubMed1998

Positioning the library at the epicenter of the networked biomedical enterprise.

The changing economic environment in which our biomedical enterprises operate presents unparalleled opportunities to the profession of medical librarianship. Evidence-based medicine, patient empowerment, asynchronous learning networks, and research colaboratories each involve a new type of shared information, or access to information in new ways or by different people. These tasks are ones with which librarianship is directly involved. Librarians are therefore placed perfectly to provide new products and services. To position the library at the epicenter of the networked biomedical enterprise we must meet three challenges: We must align the library's business strategy with that of the larger enterprise. We must provide services in ways that will scale-up to enable new business strategies. We must measure the effectiveness of services in ways that document their role in supporting the enterprise.

Community Networks↗
PubMed1998

Implementation of organizational practices to protect information in health organizations.

In March of 1997, the National Research Council (NRC) of the National Academy of Sciences issued the report, "For the Record: Protecting Electronic Health Information." In its report, the Council recommended both technical and organizational practices to protect electronic health information. At the time the report was issued, Vanderbilt University Medical Center was deeply immersed in the development of organizational practices consistent with the Council's recommendations. We agreed that the recommended technical and organizational practices are important for protecting other information types in addition to health information, and that they suggest appropriate practices for non-electronic information, as well. In this paper, we focus on our process for developing and implementing the seven organizational practices recommended for immediate implementation.

Academic Medical Centers↗
PubMed1997

The origin and erratic global spread of tuberculosis. How the past explains the present and is the key to the future.

Although tuberculosis is a disease known in antiquity, it was not distributed equally or simultaneously throughout the world. Recent genetic studies of the various species of mycobacteria give strong evidence of evolution of M. tuberculosis from saprophytic soil bacteria to M. bovis, which attacks a wide spectrum of lower animals, and then to M. tuberculosis, with the pathogenicity largely limited to humans. The great discrepancies in the time of arrival of this organism to diverse parts of the world, and in its ability to kill the young, account for significant differences in the emergence of innate resistance to tuberculosis in various populations. Innate resistance to particular infections are highly specific, and are derived from whatever scourge one's ancestors had to survive.

Animals↗
PubMed1997

Interpretation of restriction fragment length polymorphism analysis of Mycobacterium tuberculosis isolates from a state with a large rural population.

Epidemiologic relatedness of Mycobacterium tuberculosis isolates from Arkansas residents diagnosed with tuberculosis in 1992-1993 was assessed using IS6110- and pTBN12-based restriction fragment length polymorphism (RFLP) and epidemiologic investigation. Patients with isolates having similar IS6110 patterns had medical records reviewed and were interviewed to identify epidemiologic links. Complete RFLP analyses were obtained for isolates of 235 patients; 78 (33%) matched the pattern of > or = 1 other isolate, forming 24 clusters. Epidemiologic connections were found for 33 (42%) of 78 patients in 11 clusters. Transmission of M. tuberculosis likely occurred many years in the past for 5 patients in 2 clusters. Of clusters based only on IS6110 analyses, those with > or = 6 IS6110 copies had both a significantly greater proportion of isolates that matched by pTBN12 analysis and patients with epidemiologic connections, indicating IS6110 patterns with few bands lack strain specificity. Secondary RFLP analysis increased specificity, but most clustered patients still did not appear to be epidemiologically related. RFLP clustering in rural areas may not represent recent transmission.

Adolescent↗
PubMed1997

Retrospective detection of laboratory cross-contamination of Mycobacterium tuberculosis cultures with use of DNA fingerprint analysis.

In 1992-1993, we investigated possible cross-contamination of Mycobacterium tuberculosis cultures as part of a study of tuberculosis in Arkansas by using DNA fingerprint analysis. Of patients whose isolates were matched, those for whom smears were negative and only one culture was positive were identified from laboratory records. Clinical, laboratory, DNA fingerprint, and epidemiological data were reviewed. Of 259 patients, nine (3.5%) were judged to be due to cross-contamination. None of these patients had a clinical course consistent with tuberculosis. All nine specimens were processed with another isolate with a matching DNA fingerprint, and epidemiological connections were not identified among any of the patients. To avoid erroneous diagnoses and unnecessary therapy and public health investigations, specimens from patients with tuberculosis whose smears are negative and only one culture is positive should be investigated for cross-contamination. An inconsistent clinical course and a DNA fingerprint that matches those of other culture-positive specimens processed concurrently, coupled with the lack of an epidemiological connection, suggest cross-contamination.

Adult↗
PubMed1997

Design of a general clinical notification system based on the publish-subscribe paradigm.

We describe the design and initial implementation of a notification sub-system, as a component of a modern information management architecture. The system, based on the publish-subscribe paradigm, provides a framework of event-based communications for the implementation of various important clinical applications including the notification of alerts and reminders with escalation algorithms, the reliable distribution of documents, and the implementation of intelligent patient-specific monitoring processes. The initial implementation of the system, providing the notification of the unit staff about new orders, indicates that the model is viable both in terms of functionality and ability to scale up.

Algorithms↗