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Biomedical subjects

H P Lehmann

Publications and source records attributed to H P Lehmann.

At least 19 recordsLinked to original sources
PubMed2001

Communication and information technology in medical education.

The past few years have seen rapid advances in communication and information technology (C&IT), and the pervasion of the worldwide web into everyday life has important implications for education. Most medical schools provide extensive computer networks for their students, and these are increasingly becoming a central component of the learning and teaching environment. Such advances bring new opportunities and challenges to medical education, and are having an impact on the way that we teach and on the way that students learn, and on the very design and delivery of the curriculum. The plethora of information available on the web is overwhelming, and both students and staff need to be taught how to manage it effectively. Medical schools must develop clear strategies to address the issues raised by these technologies. We describe how medical schools are rising to this challenge, look at some of the ways in which communication and information technology can be used to enhance the learning and teaching environment, and discuss the potential impact of future developments on medical education.

Computer-Assisted Instruction↗
PubMed2000

Reducing the paper load: computer-based patient records.

Physicians burdened with increasing paper work may find relief in computer-based patient records (CPR). CPRs may aid clinicians in the areas of billing, documentation, reporting, and data retrieval. Value-added features like decision support and event monitoring facilitate patient outcome, decrease health care costs and allow improved administration. The authors discuss obstacles in the use of computers in patient care with a focus on security, confidentiality, and Y2K.

Computer Security↗
PubMed2000

Developmental dysplasia of the hip practice guideline: technical report. Committee on Quality Improvement, and Subcommittee on Developmental Dysplasia of the Hip.

OBJECTIVE: To create a recommendation for pediatricians and other primary care providers about their role as screeners for detecting developmental dysplasia of the hip (DDH) in children. PATIENTS: Theoretical cohorts of newborns. METHOD: Model-based approach using decision analysis as the foundation. Components of the approach include the following: PERSPECTIVE: Primary care provider. OUTCOMES: DDH, avascular necrosis of the hip (AVN). OPTIONS: Newborn screening by pediatric examination; orthopaedic examination; ultrasonographic examination; orthopaedic or ultrasonographic examination by risk factors. Intercurrent health supervision-based screening. PREFERENCES: 0 for bad outcomes, 1 for best outcomes. MODEL: Influence diagram assessed by the Subcommittee and by the methodology team, with critical feedback from the Subcommittee. EVIDENCE SOURCES: Medline and EMBASE search of the research literature through June 1996. Hand search of sentinel journals from June 1996 through March 1997. Ancestor search of accepted articles. EVIDENCE QUALITY: Assessed on a custom subjective scale, based primarily on the fit of the evidence to the decision model. RESULTS: After discussion, explicit modeling, and critique, an influence diagram of 31 nodes was created. The computer-based and the hand literature searches found 534 articles, 101 of which were reviewed by 2 or more readers. Ancestor searches of these yielded a further 17 articles for evidence abstraction. Articles came from around the globe, although primarily Europe, British Isles, Scandinavia, and their descendants. There were 5 controlled trials, each with a sample size less than 40. The remainder were case series. Evidence was available for 17 of the desired 30 probabilities. Evidence quality ranged primarily between one third and two thirds of the maximum attainable score (median: 10-21; interquartile range: 8-14). Based on the raw evidence and Bayesian hierarchical meta-analyses, our estimate for the incidence of DDH revealed by physical examination performed by pediatricians is 8.6 per 1000; for orthopaedic screening, 11.5; for ultrasonography, 25. The odds ratio for DDH, given breech delivery, is 5.5; for female sex, 4.1; for positive family history, 1.7, although this last factor is not statistically significant. Postneonatal cases of DDH were divided into mid-term (younger than 6 months of age) and late-term (older than 6 months of age). Our estimates for the mid-term rate for screening by pediatricians is 0.34/1000 children screened; for orthopaedists, 0.1; and for ultrasonography, 0.28. Our estimates for late-term DDH rates are 0.21/1000 newborns screened by pediatricians; 0.08, by orthopaedists; and 0.2 for ultrasonography. The rates of AVN for children referred before 6 months of age is estimated at 2.5/1000 infants referred. For those referred after 6 months of age, our estimate is 109/1000 referred infants. The decision model (reduced, based on available evidence) suggests that orthopaedic screening is optimal, but because orthopaedists in the published studies and in practice would differ, the supply of orthopaedists is relatively limited, and the difference between orthopaedists and pediatricians is statistically insignificant, we conclude that pediatric screening is to be recommended. The place of ultrasonography in the screening process remains to be defined because there are too few data about postneonatal diagnosis by ultrasonographic screening to permit definitive recommendations. These data could be used by others to refine the conclusions based on costs, parental preferences, or physician style. Areas for research are well defined by our model-based approach.

Decision Support Techniques↗
PubMed2000

HEp2 ANA EIA: a new fully automated assay for the screening of antinuclear antibodies.

BACKGROUND: Screening for antinuclear antibodies is performed for various systemic autoimmune diseases with various different techniques. A more recent approach to ANA screening is the use of enzyme immunoassays. OBJECTIVES: To introduce the new COBAS CORE HEp2 ANA EIA, the first fully automated enzyme immunoassay for the detection of ANA in serum and plasma of patients with suspected systemic autoimmune disease. METHODS: A method comparison between the new HEp2 ANA EIA and immunofluorescence assays on HEp2 cells was performed in two groups--977 patients with systemic autoimmune disorders and 952 healthy subjects with no autoimmune disease-related diagnosis. RESULTS: The clinical sensitivity in the patient group was 79.8% for HEp2 ANA EIA and 89.5% for IFA, and the clinical specificity in the control group was 91.7% for HEp2 ANA EIA and 93.9% for IFA. The analysis of 830 routine samples showed an overall good concordance of 85% between both assays. Further examination of the discrepant results showed 8% discrepant negative results for the HEp2 ANA EIA assay compared to 21% for IFA. Discrepant positive results were found in 37.9% and 33% of samples for the HEp2 ANA EIA and the IFA, respectively. CONCLUSION: The HEp2 ANA EIA is the first fully automated assay for the detection of ANA in serum and plasma. The assay shows improved sensitivity in ANA determination and a similar performance, compared to the standard method of IFA.

Antibodies, Antinuclear↗
PubMed1999

Patient preferences for early discharge after laparoscopic cholecystectomy.

UNLABELLED: Patients may have concerns about their ability to manage postoperative symptoms at home after ambulatory surgery. We assessed patients' attitudes toward postoperative care at home or in the hospital after laparoscopic cholecystectomy. Thirty-eight patients undergoing elective laparoscopic cholecystectomy were pre- and postoperatively (within a week each) presented with scenarios describing symptoms of differing severity in either a home or hospital setting and were asked to rank and rate the relative desirability of the scenarios using rating scale, standard gamble, and willingness-to-pay techniques. Preoperatively, 16 (42%), 21 (55%), and 30 (79%) patients ranked pain of mild, moderate, and severe levels, respectively, as worse than the respective levels of nausea and vomiting. Of 24 patients, 19 (79%) preferred home care to hospital care for mild symptoms, and 12 of 22 patients (55%) preferred home care to hospital care for moderate symptoms. The average ratings were 20, 53, and 90 for mild, moderate, and severe symptoms, respectively, where 0 = no symptoms and 100 = the worst symptoms possible. Patients who preferred care outside the home indicated that they were willing to pay a mean of $142 (maximum $410) as a maximal copayment to have postoperative care in the hospital and a mean of $255 to receive care in a medical hotel-like facility. Postoperative assessment correlated highly with the preoperative assessment (correlation coefficient >0.6 for rating, standard gamble, and willingness-to-pay assessments). We conclude that patients vary in their attitudes toward where they would like to receive postoperative care. Attitudes assessed preoperatively may predict their attitudes postoperatively. IMPLICATIONS: Patients preferred to be at home for mild postoperative symptoms but in the hospital for worse postoperative symptoms. Preferences did not change with different methods of asking and were the same pre- and postoperatively. If patients made choices for their care before their procedure, they would still be happy with those decisions postoperatively.

Adult↗
PubMed1999

Restricted natural language processing for case simulation tools.

For Interactive Patient II, a multimedia case simulation designed to improve history-taking skills, we created a new natural language interface called GRASP (General Recognition and Analysis of Sentences and Phrases) that allows students to interact with the program at a higher level of realism. Requirements included the ability to handle ambiguous word senses and to match user questions/queries to unique Canonical Phrases, which are used to identify case findings in our knowledge database. In a simulation of fifty user queries, some of which contained ambiguous words, this tool was 96% accurate in identifying concepts.

Computer Simulation↗
PubMed1998

Certification standards transfer: from committee to laboratory.

The ISO 9000 Standards series were developed to provide the international manufacturing industry with a framework to ensure purchased products meet quality criteria. Section 4 of ISO 9001, Quality System Model for Quality Assurance in Design, Development, Production, Installation and Servicing, contains 20 aspects of a quality system that must be addressed by an organization in order to receive ISO 9001 certification. This concept is extended to the clinical laboratory, where a quality system program establishes for the customer (patient/clinician) that the purchased product (requested information on a submitted specimen-test result) meets established quality norms. In order to satisfy the customer, the providing organization must have policies and procedures in place that ensure a quality product, and be certified. To become certified the organization must, through an inspection process, demonstrate to an independent accrediting agency that it meets defined standards. In the United States, the government through the Clinical Laboratory Improvement Amendment (CLIA) 1988 established quality standards for the clinical laboratory. The College of American Pathologists (CAP), through its Laboratory Accreditation Program (LAP), serves as an independent agency that certifies that laboratories meet standards. To demonstrate the applicability of an established clinical laboratory accreditation program to ISO 9001 certification, the standards and checklists of CLIA 1988 and the CAP LAP will be examined to determine their conformance to ISO 9001, Section 4.

Certification↗
PubMed1998

Delivering labeled teaching images over the Web.

The Web provides educators with the best opportunity to date for distributing teaching images across the educational enterprise and within the clinical environment. Experience in the pre-Web era showed that labels and information linked to parts of the image are crucial to student learning. Standard Web technology does not enable the delivery of labeled images. We have developed an environment called OverLayer that succeeds in the authoring and delivering of such images in a variety of formats. OverLayer has a number of functional specifications, based on the literature and on our experience, among them, the following: Users should be able to find components by name or by image; to receive feedback about their choice to test themselves. The image should be of arbitrary size; should be reusable; should be linked to further information; should be stand-alone files. The labels should not obscure the image; should be linked to further information. Images should be stand-alone files that can be transferred among faculty members. Implemented in Java, OverLayer (http:/(/)omie.med.jhmi.edu/overlayer) has at its heart a set of object classes that have been reused in a number of applets for different teaching purposes and a file format for creating OverLayer images. We have created a 350-image histology library and a 500-image pathology library, and are working on a 400-image GI endoscopy library. We hope that the OverLayer suite of classes and implementations will help to further the gains made by previous image-based hyperlinked technologies.

Anatomy↗
PubMed1997

Patterns of DNA ploidy and S-phase fraction associated with breast cancer survival in blacks and whites.

A significant survival difference between black and white breast cancer patients has been observed in the United States. Evaluation of the prognostic value of DNA ploidy and S-phase fraction (SPF) in black and white breast cancer patients may contribute to our understanding of the mechanisms of racial disparity in survival. A sample of 98 patients (50 blacks and 48 whites) who participated in the Black/White Cancer Survival Study was selected for DNA flow cytometry analysis. Patients were followed between 4.5 and 6.5 years. The impacts of DNA ploidy and SPF on breast cancer survival were examined. Kaplan-Meier survival curves, log rank statistics, and Cox proportional hazards regression were used for survival analyses. Black patients were more likely than white patients to have tumors with high SPF (P < 0.05), but there was no difference in DNA ploidy (P = 0.79). Because there were significant interactions of both DNA ploidy and SPF with race, survival was examined separately for blacks and whites. Significantly poorer survival was observed for white patients with class A ploidy (hypodiploidy, hypotetraploidy, and hypertetraploidy; P = 0.001) and with high SPF (P = 0.025). The elevated hazard ratios remained significant after adjusting for age and stage. Further adjustment for adjuvant therapy and histopathological characteristics of tumor reduced the hazard ratios of SPF to a nonsignificant level. No significant associations were found between survival and DNA ploidy or SPF among blacks. DNA ploidy and SPF are prognostic factors for breast cancer survival in white patients but not in blacks. This may have clinical implication in breast cancer management.

Black People↗
PubMed1996

Implementing the Bayesian paradigm: reporting research results over the World-Wide Web.

For decades, statisticians, philosophers, medical investigators and others interested in data analysis have argued that the Bayesian paradigm is the proper approach for reporting the results of scientific analyses for use by clients and readers. To date, the methods have been too complicated for non-statisticians to use. In this paper we argue that the World-Wide Web provides the perfect environment to put the Bayesian paradigm into practice: the likelihood function of the data is parsimoniously represented on the server side, the reader uses the client to represent her prior belief, and a downloaded program (a Java applet) performs the combination. In our approach, a different applet can be used for each likelihood function, prior belief can be assessed graphically, and calculation results can be reported in a variety of ways. We present a prototype implementation, BayesApplet, for two-arm clinical trials with normally-distributed outcomes, a prominent model for clinical trials. The primary implication of this work is that publishing medical research results on the Web can take a form beyond or different from that currently used on paper, and can have a profound impact on the publication and use of research results.

Bayes Theorem↗
PubMed1995

Teaching literature searching in the context of the World Wide Web.

As part of the required curriculum for medical students, we devised a literature-searching practicum that has been used for two years. In both years, we stressed going beyond the skills needed for using a particular searching program, towards a more conceptual approach to information searching. In the first year, the practicum was taught in a traditional lecture/hands-on format. In the second year, the lecture was replaced by a World Wide Web-based tutorial (http:@www.welch.jhu.edu/Education/tutorials/pra cticum.html). To our knowledge, this is the first Web-based resource intended to teach students about appropriate use of search technology. Comparison of student evaluations showed no difference in attitude toward the two versions of the practicum, and observation of student performance suggested similar levels of proficiency. We conclude that placing these educational materials on the Web (1) makes us practice what we preach; (2) is as effective as traditional teaching methods; and (3) gives students a resource for reinforcement learning.

Computer Communication Networks↗
PubMed1994

Immunological evidence for co-expression of cluster-5 and cluster-5A small cell lung cancer antigen on a single molecule.

We have investigated immunologically the molecular association of the cell-surface sialoglycoprotein antigens cluster-5 (CL-5) and cluster-5A (CL-5A), known to be co-expressed in human small-cell lung cancer (SCLC). CL-5 antigen is exclusively defined by IgM antibodies as represented by MAb LAM8, whereas CL-5A antigen is exclusively defined by IgG antibodies as represented by MAbs SWA20 and SEN31. Because of the unavailability of purified antigens, the question of the molecular relationship between these antigens was addressed by immunological studies. We generated an anti-anti-idiotypic MAb of the IgG isotype using a CL-5-antigen-mimicking anti-idiotype defined by rat MAb Ly8-229 as an immunogen to circumvent the avidity problems observed with the IgM MAb LAM8 in binding-competition experiments. In addition, we developed a heterologous double antibody sandwich assay able to identify circulating CL-5/5A antigens in pre-treatment sera of patients with SCLC. The results of both types of immunological studies demonstrated the expression of CL-5 and CL-5A antigens on a single molecule, both in cellular assays and in assays detecting antigens shed into the serum of patients with SCLC.

Animals↗