Biomedical subjects

Geoffrey Williams

Publications and source records attributed to Geoffrey Williams.

4 recordsLinked to original sources

PubMed2006

Introducing equating methodologies to compare test scores from two different self-regulation scales.

Standardizing the measurement tools that researchers use to assess the effectiveness of interventions would strengthen our ability to compare results across studies. In practice, however, standardization is difficult to implement, in part, because researchers prefer to use measurement tools that focus specifically on the components of their interventions. This paper demonstrates the usefulness of item response modeling linking methodology in comparing groups of participants who were administered different scales intended to measure the same underlying constructs. The Treatment Self-Regulation Questionnaire (TSRQ) as it relates to diet improvement provided the empirical application to demonstrate how two different scales that measure the same construct can be compared. The results showed that two eight-item TSRQ scales can be linked if they have at least four items in common. As expected, varying the number of linking items did not affect the reliability of the results; however, it significantly affected the relative rating with respect to the 15-item scale. In health behavior and health education research, linking methodologies can be used to compare results across studies that use slightly different versions of a scale to measure the same construct.

Adult↗

PubMed2006

Managing and mining protein crystallization data.

The crystallization of macromolecules remains a major bottleneck in structural biology. The routine screening of more than one thousand crystallization conditions and subsequent optimization by fine screening presents a challenge to conventional laboratory notebook keeping. In addition, the development of high-throughput robotic crystallization and imaging systems presents a pressing need for low-cost laboratory information management system (LIMS). Here we describe CLIMS2, a crystallization LIMS that features a simple, user-friendly graphical interface, allowing the storage, management, retrieval and mining of crystallization data. The CLIMS2 executable and documentation is freely available at http://clims.med.monash.edu.au.

Computer Graphics↗

PubMed2005

Intravascular T-cell lymphoma with bowel involvement: case report and literature review.

Intravascular lymphoma (IVL) is a rare form of non-Hodgkin lymphoma characterized by massive proliferation of large, neoplastic cells in small- and medium-sized blood vessels. Most cases of IVL are of B-cell immunophenotype; fewer than 15 cases of T-cell IVL have been reported. A 23-year-old male presented with acute abdominal pain, fever, and tender lower abdomen. Pathology at laparotomy revealed infiltration of colonic vessels with large lymphoid cells compatible with IVL. We reviewed all cases of IVL diagnosed at the Queen Elizabeth II Health Sciences Centre in Halifax, Nova Scotia, from August 1992 to August 2002. A literature review was also performed. Five additional cases of IVL were identified at this institution during a 10-year period. Three patients presented with neurological symptoms, and two with abdominal pain. In 4 of 5 cases, patients died of lymphoma within 3 months of presentation; one patient experienced a 10-month remission. While visceral involvement with IVL is common at autopsy, IVL presenting as an acute abdomen in an immunocompetent patient has not previously been described. Among the 15 cases of T-cell IVL reported in the literature, only two occurred in people under age 30. Given the rarity of T-cell IVL, it is remarkable that three cases of T-cell IVL have been diagnosed at our institution during a 10-year period.

Adult↗

PubMedDate not supplied

The value of diagnostic information to patients with chest pain suggestive of coronary artery disease.

BACKGROUND: The results of diagnostic tests often have a profound impact on the way patients view their health. Decision analyses and clinical guidelines do not routinely consider this, in part because methods are not well developed for measuring the value of testing to patients. OBJECTIVES: To measure the value of stress testing to patients with chest pain suggestive of coronary artery disease (CAD) and to improve methods for measuring the value of diagnostic information. METHODS: The authors conducted a prospective cohort study of patients with chest pain who were referred from 44 primary care practices for treadmill testing (N = 320). Current health status, perceived life expectancy, anxiety, uncertainty, and preferences for current health states were measured before and 1 week after testing and receipt of the results. Patients also reported the diagnosis given by their physicians after testing. The authors used paired t tests to assess changes before and after testing. RESULTS: Perceived life expectancy lengthened, anxiety decreased, and uncertainty decreased 1 week after exercise testing, compared to before (P < 0.01). For many patients, sytoms were less bothersome after testing than before. There were few changes in perceptions of current health status, as measured by the SF-36. The authors found evidence of reassurance among patients who reported that CAD had been excluded and no evidence of psychological harm among patients who reported a new CAD diagnosis. CONCLUSIONS: Patients experienced measurable psychological benefits from noninvasive diagnostic testing for CAD. Similar measurements should be standard components of diagnostic test evaluation.

Adult↗