December 05, 2011 [posted]

What's New for 2012 MeSH®

Overview of Vocabulary Development and Changes for 2012 MeSH

454 Descriptors added
42 Descriptor terms replaced with more up-to-date terminology
15 Descriptors deleted

Totals by Type of Terminology

26,582 Descriptors
83 Qualifiers
202,066 Supplementary Concept Records (SCRs)

Helpful Links

Please consult the 2012 online Introduction to MeSH for more details. Lists of new and changed vocabulary are available at these links:

MeSH Vocabulary Changes

New Descriptors - 2012

Changed Descriptors - 2012

Deleted Descriptors - 2012

New Descriptors by Tree Subcategory - 2012

In addition, files of MeSH 2012 vocabulary are also available for downloading.

Organism and Organelle-specific Sub-concepts

MeSH had a number of descriptors that included organelle- and organism-specific terms in sub-concepts as Entry Terms. This arrangement required an additional coordinating heading to be used when searching with one of the pre-coordinated Entry Terms. For example, searchers using the highly specific MeSH Entry Term "Mitochondrial Initiation Factors" would need to use coordination with "Mitochondrial Proteins." To avoid this confusion we removed organism- and organelle-specific terms in cases where the concept merely refers to the same or nearly same protein found in a different location or different organism. For 2012 MeSH, the Entry Term "Mitochondrial Initiation Factors" no longer exists as an Entry Term to "Eukaryotic Initiation Factors." In cases where there is a distinct protein subtype that is only found in a specific organelle or organism the sub-concept was promoted to a new descriptor class.

Recombinant Proteins

In the past a series of specific recombinant protein headings were created to distinguish several pharmaceutically-significant protein classes. However, the advent of recombinant protein technology for the production of most pharmaceutical proteins has made this distinction obsolete. With this in mind we removed specific recombinant protein classes from MeSH. Citations will be maintained to the appropriate protein classes and the general heading "Recombinant Proteins." Note that defined pharmaceutical preparations of individual recombinant proteins, e.g., interferon alfa-2a, will be maintained in the supplemental concept record.

New HLA Antigens Typing System Nomenclature Introduced into MeSH

A new nomenclature system for HLA antigens was recently devised by the WHO Nomenclature Committee for Factors of the HLA System. This system was needed to support the vast number of HLA antigens that are now characterized at the level of DNA sequence. In order to make 2012 MeSH conform to the new HLA system over 370 MeSH concepts were updated and 25 new HLA-related descriptor classes were created. See Nomenclature for Factors of the HLA System for further information on how HLA antigens are named.

By Jacque-Lynne Schulman
MeSH Section

Schulman JL. What's New for 2012 MeSH®. NLM Tech Bull. 2011 Nov-Dec;(383):e8.