Biomedical subjects

W DuMouchel

Publications and source records attributed to W DuMouchel.

6 recordsLinked to original sources

PubMed2001

Transplantation of embryonic dopamine neurons for severe Parkinson's disease.

BACKGROUND: Transplantation of human embryonic dopamine neurons into the brains of patients with Parkinson's disease has proved beneficial in open clinical trials. However, whether this intervention would be more effective than sham surgery in a controlled trial is not known. METHODS: We randomly assigned 40 patients who were 34 to 75 years of age and had severe Parkinson's disease (mean duration, 14 years) to receive a transplant of nerve cells or sham surgery; all were to be followed in a double-blind manner for one year. In the transplant recipients, cultured mesencephalic tissue from four embryos was implanted into the putamen bilaterally. In the patients who received sham surgery, holes were drilled in the skull but the dura was not penetrated. The primary outcome was a subjective global rating of the change in the severity of disease, scored on a scale of -3.0 to 3.0 at one year, with negative scores indicating a worsening of symptoms and positive scores an improvement. RESULTS: The mean (+/-SD) scores on the global rating scale for improvement or deterioration at one year were 0.0+/-2.1 in the transplantation group and -0.4+/-1.7 in the sham-surgery group. Among younger patients (60 years old or younger), standardized tests of Parkinson's disease revealed significant improvement in the transplantation group as compared with the sham-surgery group when patients were tested in the morning before receiving medication (P=0.01 for scores on the Unified Parkinson's Disease Rating Scale; P=0.006 for the Schwab and England score). There was no significant improvement in older patients in the transplantation group. Fiber outgrowth from the transplanted neurons was detected in 17 of the 20 patients in the transplantation group, as indicated by an increase in 18F-fluorodopa uptake on positron-emission tomography or postmortem examination. After improvement in the first year, dystonia and dyskinesias recurred in 15 percent of the patients who received transplants, even after reduction or discontinuation of the dose of levodopa. CONCLUSIONS: Human embryonic dopamine-neuron transplants survive in patients with severe Parkinson's disease and result in some clinical benefit in younger but not in older patients.

Adult↗

PubMed1995

Unlocking clinical data from narrative reports: a study of natural language processing.

OBJECTIVE: To evaluate the automated detection of clinical conditions described in narrative reports. DESIGN: Automated methods and human experts detected the presence or absence of six clinical conditions in 200 admission chest radiograph reports. STUDY SUBJECTS: A computerized, general-purpose natural language processor; 6 internists; 6 radiologists; 6 lay persons; and 3 other computer methods. MAIN OUTCOME MEASURES: Intersubject disagreement was quantified by "distance" (the average number of clinical conditions per report on which two subjects disagreed) and by sensitivity and specificity with respect to the physicians. RESULTS: Using a majority vote, physicians detected 101 conditions in the 200 reports (0.51 per report); the most common condition was acute bacterial pneumonia (prevalence, 0.14), and the least common was chronic obstructive pulmonary disease (prevalence, 0.03). Pairs of physicians disagreed on the presence of at least 1 condition for an average of 20% of reports. The average intersubject distance among physicians was 0.24 (95% Cl, 0.19 to 0.29) out of a maximum possible distance of 6. No physician had a significantly greater distance than the average. The average distance of the natural language processor from the physicians was 0.26 (Cl, 0.21 to 0.32; not significantly greater than the average among physicians). Lay persons and alternative computer methods had significantly greater distance from the physicians (all > 0.5). The natural language processor had a sensitivity of 81% (Cl, 73% to 87%) and a specificity of 98% (Cl, 97% to 99%); physicians had an average sensitivity of 85% and an average specificity of 98%. CONCLUSIONS: Physicians disagreed on the interpretation of narrative reports, but this was not caused by outlier physicians or a consistent difference in the way internists and radiologists read reports. The natural language processor was not distinguishable from the physicians and was superior to all other comparison subjects. Although the domain of this study was restricted (six clinical conditions in chest radiographs), natural language processing seems to have the potential to extract clinical information from narrative reports in a manner that will support automated decision-support and clinical research.

Humans↗

PubMed1995

Medical decision support: experience with implementing the Arden Syntax at the Columbia-Presbyterian Medical Center.

We began implementation of a medical decision support system (MDSS) at the Columbia-Presbyterian Medical Center (CPMC) using the Arden Syntax in 1992. The Clinical Event Monitor which executes the Medical Logic Modules (MLMs) runs on a mainframe computer. Data are stored in a relational database and accessed via PL/I programs known as Data Access Modules (DAMs). Currently we have 18 clinical, 12 research and 10 administrative MLMs. On average, the clinical MLMs generate 50357 simple interpretations of laboratory data and 1080 alerts each month. The number of alerts actually read varies by subject of the MLM from 32.4% to 73.5%. Most simple interpretations are not read at all. A significant problem of MLMs is maintenance, and changes in laboratory testing and message output can impair MLM execution significantly. We are now using relational database technology and coded MLM output to study the process outcome of our MDSS.

Academic Medical Centers↗

PubMed1989

A Bayesian methodology for scaling radiation studies from animals to man.

This paper describes a Bayesian methodology for integrating studies in experimental animals and humans to obtain a risk estimate for a radionuclide for which no data or very limited human data are available. The method is quite general and is not limited to radiation studies. In fact, it was first developed for chemical toxicants. The methodology is illustrated using studies with rats, beagles, and humans exposed to isotopes of Ra and Pu. The goal is a quantitative risk estimate for bone cancer in humans exposed to internally deposited Pu. The choice of bone cancer as an end point and of Pu as the source of exposure was made partially because of its inherent interest but also because of issues of data availability and suitability. We performed Poisson regression analyses on 13 of 15 data sets. These analyses form the basis for the unifying method of interpreting the entire ensemble of studies. Each of the studies is summarized by the estimated dose-response slope and its estimated standard error. These summary statistics are combined with other available biological and physical information about species differences, physical and metabolic characteristics of isotopes, disease mechanisms, and the like. This information enters the analysis in the form of prior assumptions about the parameters of the Bayesian model combining the studies. The posterior distribution for the bone cancer rate in man from the Bayesian analysis of the 13 studies is updated with the limited data on Pu in humans. This update gives the final probability density for the bone cancer rate in humans exposed to internally deposited Pu. This density has a median of about three cancers per 100 Gy and has a 95% probability interval from 0.8 to 11 bone cancers per 100 Gy.

Animals↗

PubMedDate not supplied

Computer-generated informational messages directed to physicians: effect on length of hospital stay.

OBJECTIVE: With the advent of hospital payment by diagnosis-related group (DRG), length of stay (LOS) has become a major issue in hospital efforts to control costs. Because the Columbia-Presbyterian Medical Center (CPMC) has had above-average LOSs for many DRGs, the authors tested the hypothesis that a computer-generated informational message directed to physicians would shorten LOS. DESIGN: Randomized clinical trial with the patient as the unit of randomization. SETTING AND STUDY POPULATION: From June 1991 to April 1993, at CPMC in New York, 7,109 patient admissions were randomly assigned to an intervention (informational message) group and 6,990 to a control (no message) group. INTERVENTION: A message giving the average LOS for the patient's admission or provisional DRG, as assigned by hospital utilization review, and the current LOS, in days, was included in the main menu for review of test results in the hospital's clinical information system, available at all nursing stations in the hospital. MAIN OUTCOME MEASURE: Hospital LOS. RESULTS: The median LOS for study patients was 7 days. After adjustment for covariates including age, sex, payor, patient care unit, and time trends, the mean LOS in the intervention group was 3.2% shorter than that in the control group (p = 0.022). CONCLUSION: Computer-generated patient-specific LOS information directed to physicians was associated with a reduction in hospital LOS.

Analysis of Variance↗

PubMedDate not supplied

A meta-analysis of 16 randomized controlled trials to evaluate computer-based clinical reminder systems for preventive care in the ambulatory setting.

OBJECTIVE: Computer-based reminder systems have the potential to change physician and patient behaviors and to improve patient outcomes. We performed a meta-analysis of published randomized controlled trials to assess the overall effectiveness of computer-based reminder systems in ambulatory settings directed at preventive care. DESIGN: Meta-analysis. SEARCH STRATEGY: Searches of the Medline (1966-1994), Nursing and Allied Health (1982-1994), and Health Planning and Administration (1975-1994) databases identified 16 randomized, controlled trials of computer-based reminder systems in ambulatory settings. STATISTICAL METHODS: A weighted mixed effects model regression analysis was used to estimate intervention effects for computer and manual reminder systems for six classes of preventive practices. MAIN OUTCOME MEASURE: Adjusted odds ratio for preventive practices. RESULTS: Computer reminders improved preventive practices compared with the control condition for vaccinations (adjusted odds ratio [OR] 3.09; 95% confidence interval [CI] 2.39-4.00), breast cancer screening (OR 1.88; 95% CI 1.44-2.45), colorectal cancer screening (OR 2.25; 95% CI 1.74-2.91), and cardiovascular risk reduction (OR 2.01; 95% CI 1.55-2.61) but not cervical cancer screening (OR 1.15; 95% CI 0.89-1.49) or other preventive care (OR 1.02; 95% CI 0.79-1.32). For all six classes of preventive practices combined the adjusted OR was 1.77 (95% CI 1.38-2.27). CONCLUSION: Evidence from randomized controlled studies supports the effectiveness of data-driven computer-based reminder systems to improve prevention services in the ambulatory care setting.

Ambulatory Care↗