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Biomedical subjects

W Sumner

Publications and source records attributed to W Sumner.

At least 19 recordsLinked to original sources
PubMed2003

Estimating the health consequences of replacing cigarettes with nicotine inhalers.

BACKGROUND: A fast acting, clean nicotine delivery system might substantially displace cigarettes. Public health consequences would depend on the subsequent prevalence of nicotine use, hazards of delivery systems, and intrinsic hazards of nicotine. METHODS: A spreadsheet program, DEMANDS, estimates differences in expected mortality, adjusted for nicotine delivery system features and prevalence of nicotine use, by extending the data and methods of the SAMMEC 3 software from the US Centers for Disease Control and Prevention. The user estimates disease risks attributable to nicotine, other smoke components, and risk factors that coexist with smoking. The public health consequences of a widely used clean nicotine inhaler replacing cigarettes were compared to historical observations and public health goals, using four different risk attribution scenarios and nicotine use prevalence from 0-100%. MAIN OUTCOME MEASURES: Changes in years of potential life before age 85 (YPL85). RESULTS: If nicotine accounts for less than a third of smokers' excess risk of SAMMEC diseases, as it most likely does, then even with very widespread use of clean nicotine DEMANDS predicts public health gains, relative to current tobacco use. Public health benefits accruing from a widely used clean nicotine inhaler probably equal or exceed the benefits of achieving Healthy People 2010 goals. CONCLUSIONS: Clean nicotine inhalers might improve public health as much as any feasible tobacco control effort. Although the relevant risk estimates are somewhat uncertain, partial nicotine deregulation deserves consideration as part of a broad tobacco control policy.

Administration, Inhalation↗
PubMed2001

Dominant-negative transcription factor AP-2 augments SB-2 melanoma tumor growth in vivo.

We have previously demonstrated that the transition of melanoma to the metastatic phenotype is associated with a loss of expression of the transcription factor AP-2. To further investigate the role of AP-2 in the progression of human melanoma, we attempted to inactivate AP-2 in primary cutaneous SB-2 melanoma cells by using a dominant-negative AP-2, or AP-2B, gene. AP-2B is an alternatively spliced AP-2 variant capable of inhibiting AP-2 trans-activator function. Stable transfection of primary cutaneous melanoma SB-2 cells with the dominant-negative AP-2B gene was confirmed by RT--PCR and Northern blot analyses. Electromobility shift assay using nuclear extracts from these cell lines demonstrated decreased functional binding of AP-2B-transfected cells to the AP-2 consensus binding sequence compared with neo-transfected controls. In addition, CAT activity driven by a construct containing the AP-2 consensus binding sequence was downregulated in the AP-2B transfected cells, indicating AP-2 activity was quenched in the transfected cells. Orthotopic (subcutaneous) injection of the dominant-negative (AP-2B)-transfected cell lines into nude mice increased their tumorigenicity compared to control neo-transfected cells. The AP-2B-transfected cells displayed an increase in MMP-2 expression (by Northern blot) and MMP-2 activity (by zymography), which resulted in an increase in invasiveness through Matrigel-coated filters. The AP-2B-transfected tumors also displayed an increase in MMP-2 expression, microvessel density, and angiogenesis in vivo. These results demonstrate that inactivation of AP-2 contributes to the progression of melanoma, at least partially via deregulation of the MMP-2 gene.

Alternative Splicing↗
PubMed2001

Student documentation of multiple diagnoses in family practice patients using a handheld student encounter log.

Patient encounter logs may provide an important early opportunity to assess beginning clinical students' attention to and experience with many medical problems. However, there are reasons to doubt the completeness of traditional paper logs. The family practice clerkship at Washington University in St. Louis has tried a series of structured paper and hand held computer logs in search of a format that permits students to completely document their patients' diagnoses. The clerkship introduced a Palm computer log, designed with PumaTech's Satellite forms (R), that uses patient demographics to select a diagnosis entry screen displaying many likely diagnoses as checkboxes. Additional drop lists and combinations of drop lists provide access to less common diagnoses. Students using this log document 2.4 problems per patient on average, and as many as 14 problems in a single patient. Differences between students and preceptors are readily apparent. It is now possible to prepare students to rotate with specific preceptors, and to identify or predict gaps in experience that deserve remedial intervention.

Clinical Clerkship↗
PubMed2000

Parents' utilities for outcomes of occult bacteremia.

OBJECTIVE: To describe parents' values for outcomes of occult bacteremia using utility assessment, a quantitative method that incorporates risk preference. DESIGN: Computer-based utility assessment interview. SETTING: Urban children's hospital pediatric emergency department with 50 000 visits annually. PARTICIPANTS: Convenience sample of parents presenting with a child between 3 and 36 months. MAIN OUTCOME MEASURE: Parents' utility values for 8 outcomes from treatment of occult bacteremia: blood drawing, localized infection, hospitalization for antibiotics, meningitis with recovery, meningitis resulting in deafness, minor brain damage, severe brain damage, and death. RESULTS: Ninety-four subjects successfully completed the interview. Mean utilities were 0.9974 for blood drawing, 0.9941 for local infection, 0.9921 for hospitalization, 0.9768 for meningitis with recovery, 0.8611 for deafness, 0.7393 for minor brain damage, 0.3903 for severe brain damage, and 0.0177 for death. All values were significantly different from those that immediately preceded and succeeded (P<.0001), except for local infection vs hospitalization (P = .14). Median utilities for blood drawn, local infection, and hospitalization were 1. There were no significant differences among utilities of parents who presented with a febrile child (temperature > or =39 degrees C), or an afebrile child (temperature <39 degrees C). There were also no significant differences among utilities regardless of whether parents had children with prior experience with the outcomes. CONCLUSIONS: Assessment of utilities for outcomes of occult bacteremia yielded extremely high mean and median values for outcomes without permanent sequelae. This suggests that parents presenting to an emergency department may rationally prefer painful transient experiences, including venipuncture, for their children rather than risk even rare chances of severe outcomes.

Adult↗
PubMed2000

Development and implementation of a decision support system for carotid artery stenosis: the Carotid Ultrasound Report Enhancement (CURE).

The management of carotid artery stenosis is an art evolving into a science, increasingly informed by clinical trials of medical management versus carotid endarterectomy (CEA). Ideas about optimal management depend on the confluence of patient-specific variables, surgical expertise, and the state of medical knowledge. In this complex and progressing setting, an up-to-date decision support system could help physicians apply the latest evidence to patient care. Carotid ultrasonography (US) studies provide an excellent opportunity to aid in the therapy of carotid stenosis. We developed a Carotid US Report Enhancement (CURE) to augment carotid US reports with treatment-specific prognostic information and patient-specific portions of the American Heart Association's 1998 guideline for the management of carotid artery stenosis. In the process of designing and implementing the CURE software, we encountered and eventually solved a variety of problems. The first problem was that US test was not always precise enough to distinguish between a moderate and mild carotid stenosis. Likewise, the standard US reports did not elucidate several technical problems that decreased the reliability of the US result. Third, although 17 of 18 physicians agreed to receive the CURE reports, they requested non-incriminating wording. Fourth, vascular surgeons supervising the US laboratories were reluctant to support the CURE report if they thought it would be construed as prompting self-referral. Finally, information about some comorbid conditions (e.g. a history of atrial fibrillation) could not be obtained reliably from the patients. The result of responding to these problems is a decision support program that is increasingly robust, able to detect many of its own limitations, and capable of integrating data from multiple sources. A randomized controlled trial now in progress will evaluate the clinical impact of the CURE program.

Algorithms↗
PubMed2000

Family practice clerkship encounters documented with structured phrases on paper and hand-held computer logs.

Patient encounter logs allow faculty to monitor students' clinical experiences, especially in decentralized clerkships. However, there are generally tradeoffs involving the expressiveness of patient encounter forms, the effort required to complete the forms, and the utility of the forms for informing the clerkship director. The family practice clerkship at Washington University changed the school's standard free text, paper log to a controlled vocabulary paper log, borrowing 93 generic ICD-9 codes and the SNOMED concept of 'process at location' phrases for localized problems. Subsequently, this architecture was used in a Palm computer program. Students using the structured paper logs documented slightly more patient encounters than students using free text logs in the previous year, with similar numbers of problems per patient (1.3 to 1.4) and prevalence of common illnesses, but used the phrase structure and code vocabulary inconsistently. Students using computer logs documented many more patient encounters, but only documented 1.09 problems per patient. Students' documentation of psychosocial diagnoses declined significantly with the computer log. Although the computer program was flexible, the effort required to enter multiple problems exceeded the effort of finding similar codes on a short paper form. This problem confounds efforts to monitor exposure to complex patients and hidden medical problems. Another design for the hand-held computer log is being tested.

Clinical Clerkship↗
PubMed1999

The item generation methodology of an empiric simulation project.

The American Board of Family Practice (ABFP) is developing a computer-based testing system that will create realistic clinical encounters using an adaptation of an item generation process. Simulated patients' entire lives will be stochastically produced from a knowledge base, with constraints applied to prevent implausible simulations. The constraint mechanisms include knowledge acquisition decisions about grouping closely related medical concepts and widespread use of Bayesian networks to manage dependencies between concepts. Bayesian networks and fuzzy definitions provide stochastic variability between simulations produced from the same data. Examinees will interact with these patients using a large and stable set of queries and interventions. Multiple management plans associated with patient simulations provide a framework for scoring performance. All major components, including Health States, history generating "Lead To" objects, and Plans are reusable and often substitutable. Although initial knowledge acquisition demands are enormous, the system has good potential for low cost maintenance of content areas, and economies of scale as simulations and components are reused.

Journal Article↗
PubMed1998

Simulating patients with Parallel Health State Networks.

The American Board of Family Practice is developing a computer-based recertification process to generate patient simulations from a knowledge base. Simulated patients require a stochastically generated history and response to treatment, suggesting a Monte Carlo-like patient generation process. Knowledge acquisition experiments revealed that description of a patient's overall health as a node in a Monte Carlo model was difficult for domain experts to use, severely limited knowledge reusability, and created a plethora of awkwardly defined health states. We explored a model in which patients traverse several parallel health state networks simultaneously, so that overall health is a vector describing the current nodes from every Parallel Network. This model has a reasonable biological basis, more easily defined data, and greatly improved reuse potential, at the cost of more complex simulation algorithms. Experiments using osteoarthritis stages, weight classification, and absence or presence of gastric ulcers as three Parallel Networks demonstrate the feasibility of this approach to simulating patients.

Algorithms↗
PubMed1996

The effect of an educational intervention on the perceived risk of breast cancer.

OBJECTIVE: To appraise women's perceived risk of developing breast cancer and the effects of a physician's educational intervention on this perception. DESIGN: Longitudinal before-and-after study involving four measures of participants risk of developing breast cancer. Eligible women provided the data needed to calculate an objective estimate of their individual risk of developing breast cancer before age 80 using the Gail formula. They also provided a subjective estimate of their individual perceived risk. Then, each participant met with a general internal medicine physician who provided personalized information and education. Immediately after education, and again several months later, we reassessed each woman's perceived risk. SETTING: Physicians office. PARTICIPANTS: A convenience sample of 59 women participating in the Tamoxifen Breast Cancer Prevention Trial. Twenty-nine women returned for the follow-up risk assessment. MEASUREMENTS AND MAIN RESULTS: The median calculated risk of breast cancer before age 80 (by the Gail formula) was 15%, but the median perceived risk before educational intervention was 50%. The perceived risk after educational intervention fell to 25%. At late follow-up, the median perceived risk remained at 25%. The difference between the preeducational perceptions and the calculated estimates was significant (1) < .0001). After educational intervention, perceived risk measures shifted closer to the calculated value, but still remained significantly higher (p <.0001). CONCLUSIONS: Women often substantially overestimate their chances of getting breast cancer. Educational intervention by a physician, including explanation of an individual's calculated risk, can reduce this error. The effect of education appears to persist at least for several months.

Adult↗
PubMed1995

Variation in patient utilities for outcomes of the management of chronic stable angina. Implications for clinical practice guidelines. Ischemic Heart Disease Patient Outcomes Research Team.

OBJECTIVE: Although practice guidelines sometimes make recommendations based on symptom severity, they rarely account for how patients feel about their symptoms. To investigate the possible importance of patient preferences in treatment of ischemic heart disease, we assessed attitudes toward symptoms in patients with angina pectoris. DESIGN: Case series. SETTING: Ambulatory cardiology clinics at two tertiary care medical centers. PATIENTS: A total of 220 subjects were selected from 589 patients with chronic stable angina referred from cardiologists to achieve patients samples balanced for sex, race, and angina severity. MAIN OUTCOME MEASURES: We measured patients' attitudes toward their angina using the rating scale, time trade-off, and standard gamble utility metrics. Reliability of measurements was evaluated by repeating the assessments 2 weeks later on 50 willing patients. RESULTS: While the mean responses followed the expected patterns (those with more severe Canadian Cardiovascular Society scores chose lower utilities), attitudes toward symptoms varied substantially among patients with similarly severe angina. For example, there was a 33% chance that a patient with class II angina had a time trade-off utility that was lower (ie, more bothered by symptoms) than a patient with more severe angina (class III/IV). This variation in utilities was not due to random error in the assessments. CONCLUSIONS: Angina patients with similar functional limitation vary considerably in their tolerance for their symptoms, as measured by utilities. Our findings suggest that guidelines for the management of ischemic heart disease should be based on the preferences of the individual patient rather than on symptom severity alone.

Adult↗
PubMed1995

Assessing the preferences of patients with psoriasis. A quantitative, utility approach.

BACKGROUND AND DESIGN: Patient preferences for health outcomes can be explicitly assessed and expressed in quantitative terms known as utilities. Three standard methods for utility assessment have been used to quantify patient preferences, but these methods have not previously been applied to skin disease. Eighty-seven patients with psoriasis from a tertiary medical center were interviewed, using an interactive, computer-based utility assessment questionnaire, U-Titer. Utilities for three categories of psoriasis severity and potential adverse outcomes of methotrexate therapy were assessed by the vertical rating scale, time trade-off, and standard gamble. RESULTS: Patients assigned a broad range of utilities for each of the health states. Utilities obtained by the vertical rating scale did not correlate well with utilities obtained by standard gamble or time trade-off methods. However, utilities assessed by standard gamble and time trade-off were not significantly different. Patient characteristics such as age, gender, and education were not correlated with utility and did not explain the variation. Indicators of the patients' disease severity were not predictive of utilities for the assessed health states. The relatively high utility for liver biopsy suggests that there is less patient aversion to the procedure than suspected. CONCLUSIONS: Utilities, or quantitative measures of patient preferences for health states, are measurable and vary widely for mild, moderate, and severe psoriasis and possible adverse outcomes of methotrexate treatment. The process of elucidating individual patient utilities for various health outcomes can be used to incorporate patient preferences into the process of clinical decision making. Guidelines that are based solely on severity of symptoms, without input from patients on how they value such symptoms, must be questioned.

Adult↗
PubMed1994

Four proposals for market-based health care system reform.

A perfectly free, competitive medical market would not meet many social goals, such as universal access to health care. Micromanagement of interactions between patients and providers does not guarantee quality care and frequently undermines that relationship, to the frustration of all involved. Furthermore, while some North American health care plans are less expensive than others, none have reduced the medical inflation rate to equal the general inflation rate. Markets have always fixed uneven inflation rates in other domains. The suggested reforms could make elective interactions between patients and providers work more like a free market than did any preceding system. The health and life insurance plan creates cost-sensitive consumers, informed by a corporation with significant research incentives and abilities. The FFEB proposal encourages context-sensitive pricing, established by negotiation processes that weigh labor and benefit. Publication of providers' expected outcomes further enriches the information available to consumers and may reduce defensive medicine incentives. A medical career ladder would ease entry and exit from medical professions. These and complementary reforms do not specifically cap spending yet could have a deflationary impact on elective health care prices, while providing incentives to maintain quality. They accomplish these ends by giving more responsibility, information, incentives, and choice to citizens. We could provide most health care in a marketlike environment. We can incorporate these reforms in any convenient order and allow them to compete with alternative schemes. Our next challenge is to design, implement, and evaluate marketlike health care systems.

Education, Medical↗
PubMed1993

A review of Iliad and Quick Medical Reference for primary care providers. Two diagnostic computer programs.

Two diagnostic computer programs, Iliad (Applied Informatics Inc, Salt Lake City, Utah) and Quick Medical Reference (Camdat Corp, Pittsburgh, Pa), are commercially available. Both describe a large subset of internal medicine diseases. These programs, also called knowledge bases, have different structures and diagnostic methods and emphasize somewhat different experimental observations regarding problem solving and expert diagnostic behavior. Quick Medical Reference has more diverse reference features and emphasizes diagnostic competitors (diseases that explain similar features in a case). Iliad has better developed teaching features and emphasizes a probabilistic approach. The histories and methods of these programs place various constraints on their diagnostic capabilities, especially from a primary care perspective. Although neither program is currently likely to fill the role of an expert diagnostic consultant for a family practitioner, both have potential as unique reference and teaching tools in primary care.

Aged↗
PubMed1992

Expert systems and expert behavior.

Iliad 4.0 and QMR 2.03 are computer-based diagnostic knowledge bases that can play many roles in decision support and other areas of medical practice, but neither appears ready to assume the role of an expert diagnostic consultant. In contrast to human experts, these programs have problems related to recognition of their own limitations, interpretation of continuous data, recognition of dependent findings, selection of tests, and description of the impact of certain tests. Suggestions to improve these aspects of knowledge bases are offered.

Artificial Intelligence↗
PubMed1991

U-titer: a utility assessment tool.

We have developed an automated, modular utility assessment software package called U-titer. The package implements the rating scale, category scaling, standard gamble, chronic and temporary time trade-off methods of assessing patient's preferences, and allows extensive tailoring of each method. In addition to calculating utilities, U-titer records information on the process experienced by the user. It can use information gathered in one module to coordinate another module. Our early experience suggests U-titer assessments are similar to traditional assessments. This software should facilitate both the study of patient's utilities and the study of the assessment methods and their implementation.

Attitude to Health↗
PubMed1991

An evaluation of readable preventive health messages.

Distributing printed preventive health material has not been shown to change patient behavior. The lack of effect could be due to unreadable or boring materials. This could be corrected by choosing appropriate literature for each patient. A computer program was written to print booklets of relevant preventive health information matched by SMOG or Spache readability scores to a patient's self-reported educational level. The system was evaluated by printing booklets for 81 randomly selected new patients entering a family practice residency clinic setting, using the clinic's health history questionnaire to choose relevant preventive health information. After three months, patients showed no increase in obtaining flexible sigmoidoscopy, diphtheria-tetanus boosters, or cholesterol screens, when compared to 213 control patients. Use of readability matched materials in patient education efforts is logical, but was not sufficient to affect preventive health behavior in this study.

Adult↗