CTD Help: Chemicals

Contents

  1. Overview
  2. Basics
  3. Hierarchies
  4. Footnotes

Overview

CTD's chemical vocabulary is a modified subset of descriptors from the “Chemicals and Drugs” category and Supplementary Concept Records from the U.S. National Library of Medicine (NLM) Medical Subject Headings (MeSH®), a hierarchical vocabulary used to index articles for MEDLINE®/PubMed®.[1] In contrast to MeSH at NLM, CTD merged the descriptors and supplementary concepts into a single hierarchy.

The CTD vocabulary is structured as a tree in which a term may appear as a node in more than one branch. A term may have different descendant terms in each branch in which it appears.

Several branches of the original MeSH vocabulary were excluded from CTD's chemical vocabulary because they are not molecular reagents, environmental chemicals or clinical drugs (e.g., “Nucleic Acids, Nucleotides, and Nucleosides” and “Purines”). Other branches were excluded because they are simply broad chemical classes that do not contain more specific terms (e.g., “Solutions” and “Poisons”).

Chemical drawings and cross-references to other databases are supplied by ChemIDplus®, an NLM TOXNET® resource.

You may browse or query the vocabulary for related gene or reference information integrated with CTD, or to identify supplementary information about a broad range of chemicals.

Top Top of page Basics

Names, Synonyms, CAS Registry Number, etc.

The name of the chemical. It may also have a CAS Type 1 Name, CAS Registry Number, and synonyms.

Definition

A short definition of this chemical (from MeSH scope notes).

Chemical Drawing

A drawing from ChemIDplus of the two-dimensional structure of the chemical.

MeSH® ID

The unique identifier assigned to the chemical by MeSH, and a link to the source record for the chemical.

Curator Note(s)

Explanatory comments added by a CTD curator.

Top Interacting Genes

Specific chemical–gene and protein interactions in vertebrates and invertebrates are being curated from the published literature. This chart provides a view of the ten genes with the most curated interactions for this chemical. The colored bars are linked to corresponding interactions within the interaction report for this chemical (see Interactions tab).

Use Term in Query

Click the Use button to add this term to the Chemical field on the query form.

Top Top of page Hierarchies

Each chemical occurs in at least one location of the vocabulary hierarchy; many occur in more than one. Each branch of the hierarchy is presented separately, with both its ancestor path and descendant tree shown.

Nodes are indented to indicate their relative level in the tree. A node marked by the + symbol has additional descendants that are not displayed on the current page. Click a term in the ancestor path to move up the tree, or click a descendant node to move down.

If you arrived at this page from a query form, you may click the Use button to add a chemical node to the Chemical field on the query form. Searching by node (rather than by the chemical name) will yield only those items related to nodes in a particular tree.

Top Top of page Footnotes

[1]
Lipscomb CE. Medical Subject Headings (MeSH). Bull Med Libr Assoc. 2000 Jul;88(3):265-6. [PubMed:10928714]