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Medical Subject Headings

Changes in PT and MH Tags

This page describes a new XML file for citation maintenanceinformation. For 2007 MEDLINE citations having eight MeSHCategory V Descriptors, formerly indexed with the MH tag, are nowindexed with the PT tag. The Descriptors are:

Comparative Study
English Abstract
In Vitro
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.
Research Support, U.S. Gov't, P.H.S.
Research Support, N.I.H., Intramural
Research Support, N.I.H., Extramural

See also the article MeSH® Category V Terms ... NLM Technical Bulletin, September-October, 2006.

While not a change in MeSH data, the change in tags fallswithin the broader scope of GCM data, which is to make availablethe annual changes which are made by NLM in the MeSH indexing ofcitations in PubMed and distributed MEDLINE. Therefore, we areproviding these changes in XML format.

Note, however, that this type of change is not routine. Theremay or may not be similar changes in the future.

Like the existing GCM XML, maintenance data involve "tasks" -specific database transactions, which add, delete, or replacesome MEDLINE data. See CitationMaintenance tasks in XML format. The XML format is alsosimilar but does include two additional elements and anadditional attribute, so the DTD is different. The followingtable lists all the elements in the GCM_PT2007.XML file, with theelements new to the file indicated with an asterisk (*).

GCM_PT2007.XML

Element/attributeValue RangeDescription
CitMaintTaskSetSet of all tasks. Root element.
CitMaintTaskSpecific task to replace, add, ordelete indexing data.
/ActionReplace, Add, DeleteNature of the change to thecitation.
/TaskSourceTypeManual, Automatic, PrefTermProcess by which task wascreated.
MTaskIDM..., A...., P....Unique identifier for the task.Leading alphabetic, remainder numeric.
MeSHYear(YYYY)Year when annual MeSH changes firstappear in January.
ExistingMeSHUID......, C......, Q......UI of the MeSH record referencebeing replaced or deleted. Null when Action is Add. Same value asNewMeSHUI for PrefTterm change.
NewMeSHUID......, C......, Q.....UI of the MeSH record referencereplacing the old value, or being added. Null when Action isDelete. Same value as ExistingMeSHUI when only preferred termbeing changed. May include attached Qualifier UI.
ExistingMeSHPrefTerm(string)Preferred term forExistingMeSHUI.
NewMeSHPrefTerm(string)Preferred term for NewMeSHUI.
ExistingMeSHRecTypeDESCRIPTOR, SCR, QUALIFIER
NewMeSHRecTypeDESCRIPTOR, SCR, QUALIFIER
MajorTopicYNY, NNew value may be marked as the majortopic of the citation.
ExistingCitationField *MH, PTCitation tag to be replaced.
NewCitationField *MH, PTCitation tag to replace the oldtag.
Sequence(positive integer)Order in which tasks must berun.

* Only in the GCM_PT.DTD

Alphabetic List of XML elements different fromGCM.XML

The following are the elements in the two XML files. For thecomplete list see Citation Maintenancetasks in XML format.

<ExistingCitationField>
Description: The MEDLINE citation tag which is being replaced.To date, only the 'MH' tag has been used as a value for thiselement.
Example:

  <ExistingCitationField>MH</ExistingCitationField>

Subelement of: <CitMaintTask>
In file: GCM.XML, GCM_PT.XML
Required element: no

<NewCitationField>
Description: The MEDLINE citation tag which is replacing anexisting tag. To date, only the 'PT' tag has been used as a valuefor this element.
Example:

   <NewCitationField>PT</NewCitationField>

Subelement of: <CitMaintTask>
In file: GCM.XML, GCM_PT.XML.
Required element: no

TaskSourceType
Description: Process by which task was created. One of thefollowing: PrefTerm, Automatic, Manual,CitationFieldChange.
Example:

   <CitMaintTask Action="Replace" TaskSourceType="CitationFieldChange">

Subelement of: n/a; attribute of <CitMaintTask>
In file: GCM.XML,GCM_PT.XML
Required element: yes