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November 19, 2008 [posted]

What's New for 2009 MeSH®

Overview of Vocabulary Development and Changes for 2009 MeSH

Totals by Type of Terminology

Helpful Links

Please consult the 2009 online Introduction to MeSH for more details. Lists of new and changed vocabulary are available at these links:

New Descriptors - 2009
Changed Descriptors - 2009
Deleted Descriptors - 2009
New Descriptors by Tree Subcategory - 2009

In addition, files are also available for downloading.

Major Tree Revisions

Of special note are developments for 2009 MeSH related to fungi, to processes and phenomena, and to disciplines and occupations.

A major revision of the Fungi trees was undertaken to bring MeSH in synchrony with a new consensus report that revised the higher level fungi taxa (Mycol Res. 2007 May;111(Pt 5):509-47. Epub 2007 Mar 13. Cited in PubMed; PMID 17572334). As a result, some descriptors for fungi phyla became obsolete. New descriptors were added including a large number of fungi genera.

Changes to G and H Trees
Two of the MeSH Tree categories have been substantially revised and renamed. Category G (Biological Sciences) was renamed Phenomena and Processes. Category H (Natural Sciences) was renamed Disciplines and Occupations. These rearrangements were undertaken to improve the usability of the vocabulary in the G and H Tree categories.

The previous (pre-2009) organization was established in 1975 and non-biological phenomena and techniques were organized within broad disciplines named by a descriptor in the H Tree category of Natural Sciences. The Biological Sciences discipline descriptors were treed in locations in both G and H Tree categories. Phenomena, Related techniques, and similar descriptors were arranged side by side with subdisciplines. Many descriptors involving concepts related to phenomena, being of interest to more than one discipline, were placed in more than one Tree location. This arrangement was difficult to maintain and to use. To address this situation, "Phenomena and Processes" and "Disciplines and Occupations" were separated into different tree categories.

Topics of interest to a specific discipline are now organized in increasing levels of complexity. Progessive division involves separation of the phenomena into structures or objects in the case of those not represented by anatomical structures in the A category, organisms in the B category, or chemical substances in the D category. Further division follows under processes or other observable properties, qualities, and measurable phenomena. This approach provides a reproducible, logical framework for expanding the MeSH vocabulary in the category of Phenomena and Processes.

The H Tree category now provides a place for the different subcategories of disciplines and occupations. The first two of these are the Natural Sciences Disciplines and the Health Occupations.

In this major rearrangement of the G and H hierarchies, descriptors for phenomenon or process concepts in the H01 tree were moved to a G category tree. Descriptors for disciplines or occupations that were located in G were moved to H. In addition, some descriptors for techniques were moved from the former H01 subcategory of Natural Sciences to the appropriate E Tree category or elsewhere. The descriptors in G03, formerly Environment and Public Health, were moved to N06 Environment and Public Health. The descriptors for matters of interest to these disciplines are now treed in the new subtree G16.500 Ecological and Environmental Phenomena.

There are two new H Tree categories for the discipline-related terminology previously included in both G Tree categories and H Tree categories:

H01 - Natural Science Disciplines

H02 - Health Occupations (formerly G02)

New trees within G category are:

G01 - Physical Phenomena

G02 - Chemical Phenomena - includes Biochemical Phenomena (formerly G06.184)

G17 - Mathematical Concepts

New Tree categories were added for:

G03 - Metabolic Phenomena (formerly G06.535)

G04 - Cell Physiological Phenomena (formerly G04.335)

G05 - Genetic Phenomena (formerly G13) - replaces and includes Genetic Processes and includes Genetic Structures (formerly G14)

G06 - Microbiological Phenomena (formerly G04.185.515)

G12 - Immune System Phenomena (formerly G04.610)

G13 - Integumentary System Physiological Phenomena (formerly G10.795)

G14 - Ocular Physiological Phenomena (formerly G11.697)

G15 - Plant Physiological Phenomena (formerly G04.742)

G16 - Biological Phenomena (formerly G04.185)

These G Tree categories were renamed:

G07 - Physiological Phenomena - includes Nutritional Physiological Phenomena (formerly G06.696) and Pharmacological Phenomena (formerly G12)

G08 - Reproductive and Urinary Physiological Phenomena

G09 - Circulatory and Respiratory Physiological Phenomena

G10 - Digestive System and Oral Physiological Phenomena

G11 - Musculoskeletal and Neural Physiological Phenomena

By Jacque-Lynne Schulman
MeSH Section

Schulman J. What's New for 2009 MeSH®. NLM Tech Bull. 2008 Nov-Dec (365):e9.

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