Lister Hill Letter
Newsletter of the Lister Hill Library of the Health Sciences at UAB

September/October 2001

Black holes in the medical literature?

A Johns Hopkins panel investigating the June 2001 death of a volunteer in a Johns Hopkins University asthma study concluded that the principal researcher may have neglected to do a thorough search of the literature on the drug hexamethonium before the drug was used in a clinical investigation. The researcher searched PubMed, which indexes articles back to 1966, as well as a limited number of other resources, but missed earlier reports of the drug's toxicity. Medical journal articles published in the 1950s apparently warned of lung damage caused by hexamethonium.  See http://www.hopkinsmedicine.org/researchvolunteerdeath.html.

What can be done to ensure that a literature search is, at the very least, adequate for patient safety? Here is a brief guide to searching the medical literature.

I. The Resources

MEDLINE Advantages

• MEDLINE is the online version of Index Medicus, covering approximately 4300 biomedical journals, from 1966 to the present.
• MEDLINE is an excellent place to start searching. It is an indispensable database resource.
• Many researchers are familiar with MEDLINE. Lister Hill Library has supported OVID Web MEDLINE for several years. The National Library of Medicine has its own MEDLINE format, PubMed, which is updated daily and is increasingly popular for its currency.

• MEDLINE should not be considered the endpoint of comprehensive literature searching.
• MEDLINE's journal coverage is extensive but it represents only a portion, possibly just a third, of the number of biomedical journals published worldwide.
• Most MEDLINE records are from English-language sources or have English abstracts, and while taken from highly respected journals, may have an English-language bias.

Prior to 1966
 

• MEDLINE and OLDMEDLINE, searchable through the NLM Gateway at http://gateway.nlm.nih.gov, contain citations from 1957-1965. More details about these earlier online citations may be found at http://www.nlm.nih.gov/services/oldmed.html.
• Prior to 1957 there is NO online source from the National Library of Medicine. To cover prior years of medical literature, the print Index Medicus and other print sources must be searched manually.

Print Index Medicus and Its Companions-for earlier medical literature
LHL Reference Shelves, First Floor
 

• It is convenient to do a literature search from a campus office. However, the researcher should never discount the use of print resources. The accumulated knowledge of prior years is not always available at the click of a mouse. Libraries still house and maintain valuable print resources. These print sources may have either no electronic equivalents or, for budgetary reasons, electronic versions cannot be made available to the library's patrons.

For further information about the Index Medicus Chronology go to http://www.nlm.nih.gov/services/indexmedicus.html.

Beyond MEDLINE

There are many valuable resources, other than MEDLINE, to search. These are a few to consider:

• Lister Hill Library provides access to Web of Science, which covers Science Citation Index, Social Sciences Citation Index, and Arts & Humanities Citation Index. This resource, which goes beyond the boundaries of medical literature to include the sciences and social sciences and humanities, offers linked online coverage from 1995 to the present. The print Science Citation Index, however, is available in the reference section on the first floor of Lister Hill Library and provides coverage back to 1945. (Mervyn Sterne Library has print copies of Social Sciences Citation Index 1982-2000 and Arts & Humanities Citation Index 1975-1987.)
• Biological Abstracts (1926-). BIOSIS, the online version, is available commercially from 1990-present. Mervyn Sterne library holds print indexes from 1927-present.  (See 'Mediated Database Searching.')
• Chemical Abstracts (1907-). Online database available commercially from 1967-present. Mervyn Sterne Library holds print indexes from 1907-present. Chemical Abstracts covers the whole field of chemistry, pure and applied, including biochemistry.
• The PsycInfo database of psychological literature is available from Sterne Library's list of databases, searchable online back to 1887.
• The Agricola database, http://www.nal.usda.gov/ag98, available from the U.S. National Agricultural Library, covers agriculture subjects from 1979-present. The Bibliography of Agriculture (not available at UAB) covers agricultural literature from 1942-1978.
• TOXNET (Toxicology Data Network), a cluster of databases on toxicology, hazardous chemicals and related areas, is available from the National Library of Medicine at http://toxnet.nlm.nih.gov.

• Many librarians use the Google search engine http://www.google.com to search the Internet for difficult-to-locate items. Searching the Internet via a search engine may take patience, but can be fruitful if the information does not seem to be available through standard resources. The usual cautions about the credibility of the site and the reliability of the information apply whenever a search is made on the Internet.

Mediated Database Searching

These searches, performed only by reference librarians, are available for a fee.

• The library has access to over 500 commercial databases accessible through information vendors such as DIALOG.
• These mediated searches may be performed on databases such as BIOSIS, Chemical Abstracts, and EMBASE, which is more international in coverage than MEDLINE and includes more European journals and alternative medicine sources.
• Please contact a Lister Hill Library Reference Librarian for more information on fee-based mediated searching. This method of searching, performed by a librarian working with the database's connect-time charge system, may be expensive.

II. Searching Skills

What Went Wrong at Hopkins?

Both clinical and administrative errors may have been made at Johns Hopkins during the asthma study using hexamethonium. The initial inadequate search of the medical literature, however, probably laid the groundwork for tragedy. It is this aspect of the case that concerns medical librarians.   The limited number of resources used by the Johns Hopkins searcher impaired the comprehensiveness, or exhaustive nature, of the search.  Inadequate searching skills can pose another kind of obstacle to a good literature search by compromising the refinement, or depth, of the search.

Complexities of Database Searching

It is probable that the principal researcher in the Johns Hopkins case acted in good faith in his search of the literature. But he may have lacked an understanding of the complexity of literature searching as well as the more advanced searching skills necessary to perform adequately on his own.

• Those who are fairly new to searching, or unaware of a database's advanced features, may be easily satisfied with their first results. Librarians, who have several years of daily experience with database searching, still have to take time and thought when formulating a search strategy. The competent use of MeSH (Medical Subject Headings) vocabulary and subheadings is essential to a thorough search in the MEDLINE database.
• Please consult a Lister Hill Reference Librarian for help with advanced searching in PubMed or OVID Web MEDLINE.

New Guidelines for Literature Searching

The Medical Library Association is currently recommending the development of guidelines for literature searching.

Johns Hopkins has recently instituted new safeguards, which require the collaboration of investigators with librarians and pharmacists. This will help to ensure that the literature search is adequate to protect patients and trial participants and will uncover potential adverse side effects of drugs. Subject specialists working in tandem with librarians may contribute to a positive outcome.

If you have any doubts or questions about the completeness of your information, please contact the reference staff at Lister Hill Library. We would be happy to help.

Notes

Bor, Jonathan and Pelton, Tom. (2001, July 17). Hopkins faults safety lapses. The Baltimore Sun. Available from: URL: http://www.sunspot.net/bal-te.md.hopkins17jul17.story

Kolata, Gina. (2001, July 20).  Johns Hopkins death brings halt to U.S.-funded human research. The New York Times, National Edition, pp. A1, A16.

McLellan, Faith. 1966 and all that-when is a literature search done? Lancet. 2001 Aug 25;358(9282):646.

Perkins, Eva. Johns Hopkins' tragedy: could librarians have prevented a death? http://www.infotoday.com/newsbreaks/ nb010806-1.htm.

Ramsay, Sarah. Johns Hopkins takes responsibility for volunteer's death. Lancet. 2001 Jul 21;358(9277):213.