MeSH Identifiers in OCLC Records

Users of OCLC Connexion® may have noticed that some records containing Medical Subject Headings (MeSH) subjects (MARC tag 650 with a second indicator of 2) include a subfield $0 with a MeSH authority control number.

Example: 650 #2 Lung Neoplasms $0(DNLM)D008175

This comes from a recent OCLC process to systematically control MeSH headings in records new to or newly replaced in WorldCat, based on data supplied in NLM MeSH-MARC files. When a heading is controlled, a link is made between the bibliographic record and the MeSH authority record, so if the MeSH changes, all the associated linked bibliographic records are updated as well.

Since 2016, users of WorldShare Record Manager are also able to control a MeSH heading as part of the cataloging process. In Record Manager, a controlled heading appears as underlined and in blue in the bibliographic record, and when you mouse over the controlled heading, the MeSH authority control number is displayed.

Example:650 #2 Lung Neoplasms

($0(DNLM)D008175 presented as mouse over)

Connexion users are not able to control MeSH headings, but any MeSH heading that is controlled in Record Manager will display in Connexion with a subfield $0 containing the MeSH authority control number. This subfield $0 should not be removed from the master records in WorldCat.