Medical Literature Analysis and Retrieval System (MEDLARS)

Paper: MLIS-101: Information System and Programmes
Unit No: 5
Name Abbreviation Established Headquarters Address & Contact Details URL
International Nuclear Information System INIS 1970 Vienna International Centre, PO Box 100 1400 Vienna, Austria
Contact: (+43-1) 2600-0, Fax: (+43-1) 2600-7		 https://www.iaea.org/resources/databases/inis

1. Medical Literature Analysis and Retrieval System (MEDLARS)

MEDLINE, also known as MEDLARS Online, is a significant bibliographic database housing a wealth of life sciences and biomedical information. This repository encompasses bibliographic details of articles sourced from academic journals across diverse fields, including medicine, nursing, pharmacy, dentistry, veterinary medicine, and healthcare. Its origins trace back to 1964 when it was established as MEDLARS (Medical Literature Analysis and Retrieval System) - a computerised storage and retrieval system within the National Library of Medicine (NLM) in the United States. Its primary objective was to provide bibliographic access to the extensive biomedical literature curated by the NLM.
In addition to encompassing articles from various medical disciplines, MEDLINE also comprehensively covers literature in biology, biochemistry, and fields such as molecular evolution. Compiled by the National Library of Medicine, MEDLINE is easily accessible online and can be explored using platforms like PubMed and the National Center for Biotechnology Information's Entrez system.
The inception of MEDLARS can be traced back to the National Library of Medicine Index Mechanization Project from 1958-60. By early 1964, the system was operational. MEDLARS functioned as a computerised information retrieval system offering three major types of products: (i) complex one-shot demand searches, (ii) recurring bibliographies focused on specialised fields within medical sciences, and (iii) compilation of a comprehensive periodical index known as the Index Medicus.

2. History

The National Library of Medicine (NLM), situated on the National Institutes of Health campus in Bethesda, Maryland, has been a hub for pioneering information innovation since its establishment in 1836. As the world's largest biomedical library, the NLM curates an extensive print collection and generates electronic information resources covering a broad spectrum of subjects. These resources are accessed billions of times yearly by millions of users globally. Moreover, the NLM conducts research, development, and training in biomedical informatics and health information technology. The library also oversees a 6,000-member National Network of Libraries of Medicine, facilitating access to health information in communities throughout the United States.
MEDLARS (Medical Literature Analysis and Retrieval System) is a computerised biomedical bibliographic retrieval system inaugurated by the National Library of Medicine in 1964. It represented the first large-scale computer-based retrospective search service accessible to the general public. Since 1879, the NLM has published the Index Medicus, a monthly guide featuring medical articles from myriad journals. This immense collection of bibliographic citations was manually compiled until 1957, when plans to mechanise the Index Medicus began to take shape. The need to manipulate this information to create subsidiary products led to the detailed specification by 1960. Subsequently, a request for proposals was sent to 72 companies in 1961, resulting in a contract with the General Electric Company. The Minneapolis-Honeywell 800 computer designated to run MEDLARS was delivered to the NLM in March 1963. The development of MEDLARS incurred a cost of $3 million, and upon its completion in 1964, no other publicly available electronic storage and retrieval system of comparable magnitude existed. The initial computer configuration operated from 1964 until MEDLARS II succeeded in January 1975. Input sources into MEDLARS included biomedical journals, health science publications, books, and technical reports.
In late 1971, MEDLINE (also known as "MEDLARS Online") emerged as an online version facilitating remote searches of MEDLARS from medical libraries. This system, covering 239 journals, allowed up to 25 simultaneous online users from distant medical libraries. However, it was primarily managed by libraries, enabling researchers to submit pre-programmed search tasks to librarians and receive results in printouts, with limited real-time interaction with the NLM computer output. This setup persisted until the early 1990s despite the advent of the World Wide Web. In 1996, a free public version of MEDLINE known as PubMed was introduced with the widespread integration of efficient web browsers in home computers. This system became available to general online users in June 1997, showcasing MEDLINE searches via the Web.

3. MEDLINE

MEDLINE represents the premier bibliographic database of the U.S. National Library of Medicine (NLM), housing a vast collection of over 23 million (as of 2016) references to journal articles within the life sciences, mainly focusing on biomedicine. What sets MEDLINE apart is its indexing using the NLM Medical Subject Headings (MeSH), providing a unique organisational structure for the records.
The Literature Selection Technical Review Committee (LSTRC) meticulously determines the selection process for journals included in MEDLINE. Like those reviewing NIH grant applications, this committee comprises external experts. Additionally, journals and newsletters are chosen based on NLM-initiated reviews, emphasising particular priorities such as the history of medicine, health services research, AIDS, toxicology and environmental health, molecular biology, and complementary medicine. These reviews often involve consultations with various NIH and external experts or, at times, external organisations with collaborative ties to the NLM. MEDLINE is the foundational component of PubMed, an integral part of the Entrez series of databases provided by the NLM's National Centre for Biotechnology Information (NCBI). This database encompasses over 20 million references to journal articles in the life sciences, emphasising biomedicine, and uses the NLM Medical Subject Headings for record indexing. Its time coverage spans from 1946 to the present, incorporating some older material.
With over 5,600 (as of 2016) indexed biomedical journals, MEDLINE is an indispensable resource for biomedical researchers, facilitating access to a wealth of information within the field. National Centre for Biotechnology Information (NCBI): The National Centre for Biotechnology Information (NCBI) was established as part of the National Library of Medicine within the National Institutes of Health in Bethesda, Maryland, under a United States Public Law in 1988. Its primary objectives are: The NCBI receives support from various components: Retrieval from MEDLINE: MEDLINE utilises the Medical Subject Headings (MeSH) for effective information retrieval. Search engines tailored for MEDLINE, like Entrez and PubMed, typically employ a Boolean expression that combines MeSH terms, words from article abstracts and titles, author names, publication dates, and more. Entrez and PubMed can identify articles akin to a given one, leveraging a mathematical scoring system that evaluates the similarity between the word content in the abstracts and titles of two articles.

MeSH: The Medical Subject Headings (MeSH) represent NLM's controlled vocabulary, serving multiple purposes, including indexing articles, cataloguing books, and enabling searches in MeSH-indexed databases like MEDLINE. MeSH terminology provides a standardised means to retrieve information despite varying terminologies for similar concepts. Organised hierarchically, MeSH descriptors allow broad searches that encompass narrowly indexed articles. This hierarchical structure also facilitates browsing MeSH to locate relevant descriptors. Continually updated by subject specialists, MeSH undergoes hundreds of new concept additions and numerous modifications annually.

MEDLINE Usage: PubMed usage has seen a consistent uptrend since 2008. MEDLINE aims to strike a balance between usability, potency, and comprehensiveness. Given that MEDLINE primarily caters to professionals like medical scientists and healthcare providers, effective searching on this platform requires skill, as untrained users may find simple searches overwhelming due to the large number of returned articles. It's essential to understand that a search yielding thousands of articles may not guarantee comprehensiveness. Unlike typical Internet search engines, navigating PubMed for MEDLINE necessitates a modest investment of time. Leveraging the MeSH database to define the subject of interest is a highly beneficial method to enhance search quality. Employing MeSH terms alongside limits (such as publication date or type), qualifiers (like adverse effects or prevention and control), and text-word searching proves another effective strategy.
The selection of journals for inclusion in MEDLINE primarily hinges upon recommendations from the Literature Selection Technical Review Committee (LSTRC). Like those reviewing NIH grant applications, this committee comprises external experts. Additionally, some journals and newsletters are selected based on NLM-initiated reviews, focusing on specific priorities such as the history of medicine, health services research, AIDS, toxicology and environmental health, molecular biology, and complementary medicine. These reviews typically involve consultations with a diverse range of NIH and external experts and, in some instances, external organisations with collaborative ties to the NLM.

Broad Subject Coverage: The subject scope of MEDLINE spans biomedicine and health, encompassing a broad spectrum within the life sciences, behavioural sciences, chemical sciences, and bioengineering. This expansive coverage caters to the needs of health professionals, researchers engaged in fundamental studies and clinical care, and individuals involved in public health, health policy development, and related educational pursuits. Moreover, MEDLINE also incorporates essential elements from various life sciences essential for biomedical practitioners, educators, and researchers, including aspects of biology, environmental science, marine biology, plant and animal science, biophysics, and chemistry. The inclusion of life sciences saw significant augmentation starting in 2000. Scholarly journals comprise the majority of publications indexed in MEDLINE. At the same time, a small fraction includes select newspapers, magazines, and newsletters deemed valuable for specific segments within the broad user community of the National Library of Medicine (NLM).
As the primary component of PubMed (http://pubmed.gov), a MEDLINE/PubMed search generates a list of citations containing authors, titles, sources, and often an abstract for journal articles. Additionally, it indicates whether the full text is freely available electronically. The search process is free of charge and does not necessitate registration. An increasing number of MEDLINE citations provide links to free full-text articles archived in PubMed Central or other platforms. Depending on the publisher's access criteria, these links redirect users to the publisher's or alternative full-text provider's website. For articles not freely accessible online, the "Loansome Doc" feature within PubMed offers a straightforward method to electronically request the full-text article through the National Network of Libraries of Medicine (NN/LM). Registration is mandatory for this service, and local fees may apply.
Organisations leasing the MEDLINE database from the NLM also develop and provide services or products granting access to MEDLINE data. Access to various MEDLINE services is commonly available through medical libraries, many public libraries, and commercial sources.

MedlinePlus (http://medlineplus.gov/): MedlinePlus serves as the National Library of Medicine's web portal for consumer health information, providing authoritative and updated health information devoid of advertisements, accessible freely at any time and from anywhere. A Spanish-language version, MedlinePlus en español (http://medlineplus.gov/spanish), is also available. Additionally, a version specifically designed for cell phones and other mobile devices is at http://m.medlineplus.gov. It's important to note that MedlinePlus does not encompass an exhaustive list of every health-related web resource; instead, it curates a selective list of reliable health information sources from NIH, government bodies, and professional organisations in the U.S.

PubMed: PubMed functions as a free search engine primarily accessing the MEDLINE database, containing references and abstracts on life sciences and biomedical topics. Maintained by the United States National Library of Medicine (NLM) under the National Institutes of Health, PubMed is part of the Entrez system, allowing information retrieval. Before the inception of PubMed in January 1996, MEDLINE online access was primarily limited to institutional facilities like medical libraries. However, PubMed began private, free, and home-computerized MEDLINE searching when it was publicly introduced in June 1997, showcasing MEDLINE searches via the web.
Containing over 26 million citations for biomedical literature, PubMed encompasses citations from MEDLINE, life science journals, and online books. These citations often include links to full-text content from PubMed Central and publisher websites. PubMed covers areas within biomedicine and health, delving into aspects of the life sciences, behavioural sciences, chemical sciences, and bioengineering. Additionally, it provides access to relevant websites and links to other NCBI molecular biology resources. PubMed is a free resource supporting researchers in the field, developed and maintained by the National Centre for Biotechnology Information (NCBI) at the U.S. National Library of Medicine.

PubMed Central: PubMed Central (PMC) is a free archive housing biomedical and life sciences journal literature within the U.S. National Institute of Health's National Library of Medicine (NIH/NLM). As an initiative aligned with NLM's legislative mandate to collect and preserve biomedical literature, PMC mirrors NLM's extensive print journal collection in digital form. Launched in February 2000 and managed by NLM's National Centre for Biotechnology Information (NCBI), PMC ensures permanent access to its content, even amid evolving technology and potential digital format obsolescence.
PMC operates as a repository for journal literature contributed by participating publishers and author manuscripts submitted in compliance with NIH's Public Access Policy and similar research funding agency policies. Notably, PMC does not publish journal articles but facilitates publishers in depositing their content into the archive, allowing them to delay its release for a reasonable period post-publication. Moreover, publishers can access their deposited material at any time, free of charge. PMC's value lies in its capacity to store and cross-reference diverse data sources within a single repository. It enables users to search full-text articles efficiently and integrate this literature with various information resources, fostering research and knowledge in scientific and clinical fields. NLM collaborates internationally with other agencies, sharing PMC's goals maintaining copies of its literature in reliable international archives to bolster protection against material loss or damage while promoting innovation and permanence over the long term.

4. MEDLINE, PubMed, and PMC (PubMed Central): Key Differences

MEDLINE: PubMed: Available since 1996, PubMed houses over 25 million references, encompassing the MEDLINE database and additional types of citations: PMC (PubMed Central)

5. ICMR-NIC Centre for Biomedical Information (Indian MEDLARS Centre)

The ICMR-NIC Centre for Biomedical Information, also known as the Indian MEDLARS Centre (IMC), was established in 1986 with the primary objective of addressing the information requirements of biomedical professionals in India. This centre was set up to provide medical professionals with rapid access to relevant biomedical information, utilising resources from the National Library of Medicine's (NLM) databases and various internet resources and CD databases. It offers comprehensive support services such as training sessions, access to full-text journal articles, and a Union Catalogue of Biomedical Periodicals.
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