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Biomedical subjects

E R Siegel

Publications and source records attributed to E R Siegel.

18 recordsLinked to original sources
PubMed2005

Contribution of de novo point mutations to the overall mutational burden in mitochondrial DNA of adult rats.

This study analyzed the incidence of point mutations in mitochondrial DNA of brain and muscle tissues from young (6-month) and old (24-month) male F344 rats. Coding sequence mutations in subunit 5 of the NADH dehydrogenase gene were detected after high-fidelity PCR amplification and cloning by denaturing gradient gel electrophoresis (DGGE) assay followed by sequencing of detected mutants. In total, almost a thousand individual clones were analyzed both in brain and muscle samples. On average, mtDNA from brain tissue showed a 66% increase with age in mutation frequencies (2.3+/-1.9 vs. 3.8+/-4.5 x 10(-4) mutations/bp, mean+/-SD), which failed to reach statistical significance (p=0.45). Muscle tissues yielded substantially fewer mutants with average mutant frequencies for both young and old rats almost 10 times lower than the corresponding values in the brain tissue (0.3+/-0.4 and 0.5+/-0.6 x 10(-4), respectively). The difference in mutation accumulation between muscle and brain was highly significant in both the younger group (Chi-squared=9.7, p < or = 0.01) and in older animals (Chi-squared=10.9, p < or = 0.001). Molecular analysis of the mutated sequences revealed that almost half were identical sequences recurring in different samples and tissues. Our findings indicate that the process of mutation accumulation in mitochondria begins in the germ-line and/or during earlier stages of life, contributing up to half of the total mutational burden, whereas de novo spontaneous formation of point mutations in adulthood is far less than was anticipated.

Aging↗
PubMed2001

Enhancing communications and connectivity in Africa: the multilateral initiative on malaria (MIM) model.

The U.S. National Library of Medicine, working in concert with the Multilateral Initiative on Malaria (MIM), has developed and implemented a unique organizational and technical strategy to connect malaria research sites to the Internet for purposes of facilitating North-South scientific communications and access to electronic information resources on the Web. The model employs microwave and VSAT technologies, and shares bandwidth and costs among participating malaria research sites and their respective research funders in Mali, Kenya, Ghana, Tanzania and other sub-Saharan locations affiliated with MIM. The concept of institutional partnership is an essential element of this information technology capacity building effort, which may find applicability in other developing regions of the world with similar communications and research networking needs and capabilities.

Africa South of the Sahara↗
PubMed2000

Public library consumer health information pilot project: results of a National Library of Medicine evaluation.

In October 1998, the National Library of Medicine (NLM) launched a pilot project to learn about the role of public libraries in providing health information to the public and to generate information that would assist NLM and the National Network of Libraries of Medicine (NN/LM) in learning how best to work with public libraries in the future. Three regional medical libraries (RMLs), eight resource libraries, and forty-one public libraries or library systems from nine states and the District of Columbia were selected for participation. The pilot project included an evaluation component that was carried out in parallel with project implementation. The evaluation ran through September 1999. The results of the evaluation indicated that participating public librarians were enthusiastic about the training and information materials provided as part of the project and that many public libraries used the materials and conducted their own outreach to local communities and groups. Most libraries applied the modest funds to purchase additional Internet-accessible computers and/or upgrade their health-reference materials. However, few of the participating public libraries had health information centers (although health information was perceived as a top-ten or top-five topic of interest to patrons). Also, the project generated only minimal usage of NLM's consumer health database, known as MEDLINEplus, from the premises of the monitored libraries (patron usage from home or office locations was not tracked). The evaluation results suggested a balanced follow-up by NLM and the NN/LM, with a few carefully selected national activities, complemented by a package of targeted activities that, as of January 2000, are being planned, developed, or implemented. The results also highlighted the importance of building an evaluation component into projects like this one from the outset, to assure that objectives were met and that evaluative information was available on a timely basis, as was the case here.

Computers↗
PubMed1998

G7: a framework for international cooperation in medical informatics.

The world's major economic powers, the G7, have initiated a collaborative International research and demonstration program to exploit the benefits of information and communications technology for society. The Global Healthcare Applications Project (GHAP) is investigating a variety of informatics applications in disease specific domains, telemedicine, and multilingual textual and image database systems. This paper summarizes the nine GHAP sub-projects undertaken to date, with emphasis on those in which the U.S. is a participant. The growing use of smart card technology, especially in Europe, is adding new impetus for similar medical and health experiments in the U.S. A pilot project now underway in several Western states is described.

Computer Communication Networks↗
PubMed1997

Transitioning to the Internet: results of a National Library of Medicine user survey.

In late 1995, several months prior to the introduction of Internet Grateful Med, the National Library of Medicine (NLM) conducted a customer survey as part of its efforts to make a transition from Grateful Med to new forms of electronic information access and retrieval. A questionnaire survey was mailed to a sample of 2,500 online users randomly selected from domestic users (excluding fixed-fee users) who searched NLM databases during the second quarter of 1995. The final response rate was nearly 83% of eligible respondents. About 70% of NLM customers responding already had access to the Internet, and of those, more than 90% had access to the World Wide Web. However, only 26% of customers with Internet access were using the Internet to access NLM databases. Health care providers account for about 46% of NLM customers but, as a group, search NLM databases relatively infrequently even though they have higher-end equipment. Librarians and information professionals represent about one-fifth of NLM customers and are by far the most intensive users, but tend to have lower-end equipment. Overall, the survey results provide a strong basis for the transition to Internet-based delivery of NLM online database services, including Internet Grateful Med and the NLM family of World Wide Web sites. However, Internet access is uneven, especially in rural areas and at hospitals. This reinforces the need for continuing special outreach efforts directed at improving access for rural and hospital-based users and rural libraries, upgrading computer equipment for medical librarians, and training health care providers in more effective use of Internet-based biomedical information resources.

Chi-Square Distribution↗
PubMed1991

Evaluating the impact of MEDLINE using the Critical Incident Technique.

An adaptation of the Critical Incident Technique for the evaluation of an online information system is described. 552 users of the National Library of Medicine's MEDLINE database, interviewed by telephone and responding to a highly structured set of open-ended questions, reported 1,158 incidents in which the results of a MEDLINE search was especially helpful (or not helpful) in carrying out professional activities. Systematic analysis of these "critical incidents" produced three comprehensive and detailed views of the purposes and outcomes of MEDLINE searches: (1) why information is sought from MEDLINE; (2) the impact of MEDLINE-derived information on medical decision-making; and (3) the ultimate outcome of having (or not having) the desired information on medical situations prompting a MEDLINE search. Results revealed that MEDLINE is used to satisfy a diversity of medical needs concerning patient care, the progress of biomedical research, the quality of education received by health professionals in training, the safety and effectiveness of health care institutions, the operation of the system of third-party reimbursement, for legal decisions, and for the knowledge of the public.

Consumer Behavior↗
PubMed1980

The hepatitis knowledge base. A prototype information transfer system.

The Hepatitis Knowledge Base is a prototype computerized information-transfer system aimed at supporting the health practitioner's day-to-day diagnosis, prognosis, and treatment decisions concerned with viral hepatitis. An overview of information-transfer problems in biomedicine is presented and issues pertinent to the knowledge-base concept are discussed. The following research activities are described: selection and organization of the content of the initial draft of the complete Hepatitis Knowledge Base; the method for consensus development by a nationally distributed panel of collaborating experts on the subject matter; methods for updating the knowledge base and maintaining its currency over time; use of a computer conferencing network as the principal medium of communication among the geographically dispersed experts and the project staff; support of on-line access to the knowledge-base contents; and formative evaluation of the above methods and limited field testing of the access system.

Hepatitis, Viral, Human↗
PubMedDate not supplied

Evaluating Internet end-to-end performance: overview of test methodology and results.

OBJECTIVE: An evaluation of Internet end-to-end performance was conducted for the purpose of better understanding the overall performance of Internet pathways typical of those used to access information in National Library of Medicine (NLM) databases and, by extension, other Internet-based biomedical information resources. DESIGN: The evaluation used a three-level test strategy: 1) user testing to collect empirical data on internet performance as perceived by users when accessing NLM Web-based databases, 2) technical testing to analyze the Internet paths between the NLM and the user's desktop computer terminal, and 3) technical testing between the NLM and the World Wide Web ("Web") server computer at the user's institution to help characterize the relative performance of Internet pathways. MEASUREMENTS: Time to download the front pages of NLM Web sites and conduct standardized searches of NLM databases, data transmission capacity between NLM and remote locations (known as the bulk transfer capacity [BTC]), "ping" round-trip time as an indication of the latency of the network pathways, and the network routing of the data transmissions (number and sequencing of hops). RESULTS: Based on 347 user tests spread over 16 locations, the median time per location to download the main NLM home page ranged from 2 to 59 seconds, and 1 to 24 seconds for the other NLM Web sites tested. The median time to conduct standardized searches and get search results ranged from 2 to 14 seconds for PubMed and 4 to 18 seconds for Internet Grateful Med. The overall problem rate was about 1 percent; that is, on the average, users experienced a problem once every 100 test measurements. The user terminal tests at five locations and Web host tests at 13 locations provided profiles of BTC, RTT, and network routing for both dial-up and fixed Internet connections. CONCLUSION: The evaluation framework provided a profile of typical Internet performance and insights into network performance and time-of-day/day-of-week variability. This profile should serve as a frame of reference to help identify and diagnose connectivity problems and should contribute to the evolving concept of Internet quality of service.

Evaluation Studies as Topic↗
PubMedDate not supplied

Bibliographic retrieval: a survey of individual users of MEDLINE.

The National Library of Medicine (NLM) has been providing online access to the MEDLINE database for nearly 20 years. In recent years, there has been a shift in the composition of the user population. Nearly half the online access codes are now held by individuals who conduct their own searches of the database. The NLM has conducted a survey to identify the demographic features of this end-user population, their reasons for searching the database, their methods of access, and their satisfaction with MEDLINE as available on the NLM system.

Attitude to Computers↗
PubMedDate not supplied

Use of MEDLINE by physicians for clinical problem solving.

OBJECTIVE: To understand the ways in which computer-mediated searching of the biomedical literature affects patient care and other professional activities. Undertaken to determine the ways in which on-line access to the biomedical literature via the National Library of Medicine's MEDLINE database "makes a difference" in what physicians do when confronted with a medical problem requiring new or additional information. DESIGN: An adaptation of the Critical Incident Technique used to gather detailed reports of MEDLINE search results that were especially helpful (or not helpful) in carrying out the individual's professional activities. The individual physician was the source of the patient care incident reports. One thousand one hundred fifty-eight reports were systematically analyzed from three different perspectives: (1) why the information was sought; (2) the effect of having (or not having) the needed information on professional decisions and actions; and (3) the outcome of the search. PARTICIPANTS AND SETTING: Telephone interviews were carried out with a purposive sample of 552 physicians, scientists, and other professionals working in a variety of clinical care and other settings. Of these, 65% were direct users of MEDLINE throughout the United States, and 35% had MEDLINE searches conducted for them either at a major health sciences center or in community hospitals. RESULTS: Three comprehensive and detailed inventories that describe the motivation for the searches, how search results affected the actions and decisions of the individual who initiated the search, and how they affected the outcome of the situation that motivated the search. CONCLUSIONS: MEDLINE searches are being carried out by and for physicians to meet a wide diversity of clinical information needs. Physicians report that in situations involving individual patients, rapid access to the biomedical literature via MEDLINE is at times critical to sound patient care and favorably influences patient outcomes.

Data Collection↗