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Biomedical subjects

J L Wagner

Publications and source records attributed to J L Wagner.

12 recordsLinked to original sources

Cost effectiveness of colorectal cancer screening in the elderly.

OBJECTIVE: To assess the cost effectiveness of a periodic program of colorectal cancer screening in the elderly. DESIGN: A model was constructed of four strategies for the periodic screening of persons 65 to 85 years of age. The effect of each strategy on life expectancy and health care costs was estimated under assumptions that were uniformly unfavorable to screening. Cost and added years of life were discounted at 5% per year. Cost per year of life gained from screening was calculated for each screening strategy. DATA SOURCES: Assumptions used in the model were based on a review of pertinent studies; those studies with results more unfavorable to screening were given more weight. Strengths and weaknesses of studies are discussed. MAIN RESULTS: A program of annual fecal occult blood testing (FOBT) in the elderly would detect at least 17% of the expected cases of cancer and could cost $35,000 per year of life saved. Screening schedules that include periodic sigmoidoscopy would prevent more cases of cancer but could cost between $43,000 and $47,000 per year of life gained. These estimates are based on uncertain assumptions, but results were not extremely sensitive to further relaxation of the values of the most uncertain assumptions. In no case did the cost per year of life gained from annual FOBT exceed $55,000 or did the cost per year of life gained from FOBT with sigmoidoscopy every 5 years exceed $61,000. CONCLUSIONS: Although colorectal cancer screening is costly in the aggregate, its potential medical benefits make it a reasonably cost-effective preventive intervention for the elderly.

Aged

An experimental evaluation of a prototype public access nutrition information system for supermarkets.

Located the Nutrition for a Lifetime System (NLS-1), a prototype interactive information system, in a large supermarket to help users decrease high-fat food purchases and increase high-fiber food purchases. Study participants were randomly assigned to control (n = 23; used the NLS-1 to enter food purchases only) or experimental (n = 26; viewed videodisc instructional programs, received prompts, made commitments, received feedback from the NLS-1) conditions. According to data entered in the NLS-1 and actual food shopping receipts, experimental participants significantly reduced higher fat purchases. Increases in higher fiber purchases favored the experimental group but were not significant.

Adult

A divided attention analysis of the effects of methylphenidate on the arithmetic performance of children with attention-deficit hyperactivity disorder.

Thirteen boys with Attention-Deficit Hyperactivity Disorder (ADHD) completed 80 arithmetic problems presented on a computer screen by typing a two digit answer. On half the trials, a foot press was required to terminate a computer-generated tone presented 2 seconds before, 1 second before, 1 second after, and 2 seconds after arithmetic problem presentation. Compared to placebo, methylphenidate resulted in significantly faster reaction times (RTs) to tone probes and faster answers to arithmetic problems when the two tasks did not overlap in time, but not when simultaneous processing was required when the probe was presented 2 seconds after arithmetic problems. When dual processing taxed cognitive capacity, methylphenidate still improved accuracy on the primary arithmetic task relative to placebo, but at the expense of speed of performance on the secondary RT task. When ADHD children fail to allocate available resources to a primary cognitive task, treatment with methylphenidate may result in reallocation of existing cognitive capacity from a secondary task to the primary task.

Attention

Altering shoppers' supermarket purchases to fit nutritional guidelines: an interactive information system.

This study reports the results of one effort to help supermarket shoppers alter food purchases to make purchases (and meals) that are lower in fat and higher in fiber. A prototype interactive information system using instructional video programs, feedback on purchases with specific goals for change, weekly programs, and the ability to track user interactions and intended purchases was evaluated. The major dependent measure was users' actual food purchases as derived from participants' highly detailed supermarket receipts. After a 5- to 7-week baseline phase, participants were randomly assigned to an experimental or control condition for the 7- to 8-week intervention phase. A follow-up phase began 5 to 8 weeks after participants completed the intervention and discontinued use of the system. The results indicated that experimental participants, when compared to control participants, decreased high fat purchases and increased high fiber purchases during intervention, with evidence for some maintenance of effect in follow-up. Plans for increasing the use and impact of the system are discussed.

Dietary Fats

Costs and health consequences of cholesterol screening for asymptomatic older Americans.

To predict the consequences of cholesterol screening among elderly Americans who do not have symptoms of heart disease, we explore the cost implications of a cholesterol screening program, evaluate evidence linking hypercholesterolemia to coronary heart disease and mortality in the elderly, and describe the likely effects of therapy of hypercholesterolemia. According to our calculations, if all Americans 65 years of age and older adhered to a cholesterol screening program similar to the one proposed by the National Cholesterol Education Program, minimum annual expenditures for screening and treatment would be between $1.6 billion and $16.8 billion, depending on the effectiveness of diet and the cost of the medications used to treat hypercholesterolemia. There is no direct evidence that this program would lessen overall morbidity or extend the lives of elderly Americans.

Aged

The release of C5a in complement-activated serum does not require C6.

The influence of terminal complement components on the generation and release of the complement C5a fragment was investigated by comparing the levels of C5a in complement-activated serum with the levels of C5a produced in serum depleted of complement C6. In order to investigate the release of C5a, a modified C5a assay was developed that utilizes an anti-C5b monoclonal antibody to remove C5, C5b, and C5b-C5a complexes from samples prior to C5a assay. The modified assay was developed because the standard methodology, which includes an acid-precipitation step designed to dissociate C5a and C5b, cannot distinguish free C5a from the C5a that is bound to C5b. Therefore, the standard methodology is not capable of monitoring the influence of terminal components on C5a/C5b dissociation. Levels of C5a were measured in complement-activated whole human serum, in serum depleted of C6, and in serum containing inhibitory levels of anti-C6 Fab using both the modified C5a assay and the standard methodology. Sera were complement-activated with either zymosan to activate the alternative complement pathway or with antibody-coated sheep erythrocytes to activate the classical pathway. The levels of free C5a in C6-depleted sera after activation were equivalent to the C5a levels in activated whole serum, indicating that C6 is not required for the release of C5a from C5b. In addition, the quantity of C5a detected in zymosan-activated sera using the standard acid-precipitation methodology was greater than C5a levels when assayed using the modified immunoadsorption technique, confirming that acid-treatment enhances the C5a dissociation and promotes C5a recovery. Since the other terminal components, C7, C8, and C9, bind to C5b only after C5b only after C6 is bound, these results indicate that none of the terminal components are required for the release of C5a. Although the terminal components could influence the rate of C5a release, the quantity of C5a released in serum was entirely independent of terminal components.

Animals

Reimbursement shapes market for technology.

Methods of reimbursing health care providers affect their decisions about adoption and use of new medical technologies, but how they can elicit good decisions is unclear.

Capital Expenditures

Spontaneous cholangiocarcinoma in a ring-tailed lemur (Lemur catta).

A cholangiocarcinoma in the liver with metastasis to the regional lymph nodes was found in a male ring-tailed lemur (Lemur catta). The liver was partially replaced by a gray-white, coarsely lobulated mass. Microscopically, the tumor consisted of well circumscribed lobules of anaplastic, low cuboidal cells occasionally arranged in duct-like structures. The tumor did not involve the gallbladder.

Adenoma, Bile Duct