CHAPTER 25		INDEXING PRINCIPLES FOR CATEGORY D 
	(CHEMICALS AND DRUGS) 
 
 

25.1		Category D is an array of chemicals and drugs grouped by chemical  
structure and by pharmacological or physiological activity. It is the largest of  
the MeSH categories. 
 
Terms in Category D tend to be IM concepts when the point of the article. 
 

25.2		MeSH contains all the elements, all the major inorganic and organic  
structural groups, all major action or function groups in pharmacology, all  
major endogenous substances of the body, all major enzyme groups and all major  
chemicals of environmental and industrial significance. 
 

25.2.1	The Tree Structure given below shows the specific coverage of  
chemicals in Category D. 
 
D1		INORGANIC CHEMICALS 
D2		ORGANIC CHEMICALS	 
D3		HETEROCYCLIC COMPOUNDS 
D4		POLYCYCLIC HYDROCARBONS 
D5		ENVIRONMENTAL POLLUTANTS, NOXAE, AND PESTICIDES 
D6		HORMONES, SUBSTITUTES, ANTAGONISTS 
D7		REPRODUCTIVE CONTROL AGENTS 
D8		ENZYMES, COENZYMES, ENZYME INHIBITORS 
D9		CARBOHYDRATES AND HYPOGLYCEMIC AGENTS 
D10		LIPIDS AND ANTILIPEMIC AGENTS 
D11		GROWTH SUBSTANCES, PIGMENTS, VITAMINS 
D12		AMINO ACIDS, PEPTIDES AND PROTEINS 
D13		NUCLEIC ACIDS, NUCLEOSIDES AND NUCLEOTIDES 
D14		NEUROTRANSMITTERS AND NEUROTRANSMITTER  AGENTS 
D15		CENTRAL NERVOUS SYSTEM AGENTS 
D16		PERIPHERAL NERVOUS SYSTEM AGENTS 
D17		ANTI-INFLAMMATORY AGENTS, ANTIRHEUMATIC AGENTS, AND 		 
		INFLAMMATION MEDIATORS 
D18		CARDIOVASCULAR AGENTS 
D19		HEMATOLOGIC, GASTRIC, RENAL AGENTS 
D20		ANTI-INFECTIVE AGENTS 
D21		ANTI-ALLERGIC AND RESPIRATORY SYSTEM AGENTS 
D22		ANTINEOPLASTICS, IMMUNOSUPPRESSIVES 
D23		DERMATOLOGIC AGENTS 
D24		IMMUNOLOGIC AND BIOLOGIC FACTORS 
D25		BIOMEDICAL AND DENTAL MATERIALS 
D26		MISCELLANEOUS DRUGS AND AGENTS 
 

25.3		The subheadings available for use with Category D terms are assigned  
based on whether the term is an exogenous "chemical" or an endogenous compound.  
The subheadings listed below are AQs for various groups of Category D terms: 
 
	/administration and dosage	/genetics 
	/adverse effects		/history 
	/agonists			/immunology 
	/analogs & derivatives		/isolation & purification 
	/analysis			/metabolism 
	/antagonists & inhibitors	/pharmacokinetics 
	/biosynthesis			/pharmacology 
	/blood				/physiology 
	/cerebrospinal fluid		/poisoning 
	/chemical synthesis		/radiation effects 
	/chemistry			/secretion 
	/classification			/standards 
	/contraindications		/supply & distribution 
	/deficiency			/therapeutic use 
	/diagnostic use			/toxicity 
	/drug effects			/ultrastructure 
	/economics			/urine 
 

25.3.1		Although each of the subheadings listed above is assigned to  
at least one group of Category D terms, very few compounds have all of them as  
AQs. The front of the Annotated MeSH contains tables of Allowed Qualifiers which  
indicate in general which qualifiers are allowed with general groups of  
chemicals, but the indexer must always check the AQ field for each specific  
heading indexed. 
 

25.4		MeSH contains two basic forms of chemical headings, singular and  
plural. The singular forms refer to specific compounds, while the plural forms  
apply to groups of chemicals sharing a common property such as structure or  
pharmacological activity. A plural MeSH chemical (structure) term must never be  
used to index a specific compound, only a group of compounds sharing a common  
structure. In the examples given below, note the different types of singular  
MeSH terms and the corresponding plural terms available. 
 
				Singular			Plural 
Inorganic compounds		BORON			BORATES 
				CHLORINE			CHLORIDES 
				CYANOGEN BROMIDE	BROMIDES 
Organic compounds		CORTICOSTERONE		PREGNENEDIONES 
				HEPTACHLOR		HYDROCARBONS, CHLORINATED 
				TRETINOIN			RETINOIDS 
Drugs				ANISOMYCIN		ANTIBIOTICS 
				ACETAZOLAMIDE		DIURETICS 
				NONOXYMOL		SPERMATOCIDAL AGENTS 
Physiological compounds		CORTICOSTERONE		ADRENAL CORTEX HORMONES 
				INSULINASE		PEPTIDE HYDROLASES 
				BAND 3 PROTEIN		BLOOD PROTEINS 
 

25.5		Although MeSH contains thousands of chemical headings, indexers  
often need to index other compounds which are not available in MeSH. To enhance  
our coverage of chemicals, a separate file containing additional chemical  
records is available. Officially known as the Supplementary Chemical Records, it  
is called the Chemical Tool by indexers. A printed subset of the Chemical Tool  
is available for indexers working offline; online indexers have the entire file  
available to them. 
 

25.5.1	A typical record in the Chemical Tool looks like this: 
 
 

25.5.2	Although the records in the Chemical Tool look different than  
records for MeSH chemicals, the indexing process is similar for chemicals from  
either publication. 
 

25.5.2.1	When indexing a chemical which is a MeSH heading, the indexer should  
check where it is treed;  if the treeing adequately covers the chemical as  
discussed by the author, only the single MeSH heading needs to be indexed. 
 
	Complete amino acid sequence of the Salmonella typhi heat shock  protein  
groEL.	 
				GROEL PROTEIN / * chem 
				SALMONELLA TYPHI / * chem 
				AMINO ACID SEQUENCE 
				MOLECULAR SEQUENCE DATA 
				Not:	BACTERIAL PROTEINS / * chem  
				Not:	HEAT-SHOCK PROTEINS / * chem because GROEL PROTEIN  
					is treed under BACTERIAL PROTEINS and HEAT-SHOCK  
PROTEINS. 
 

25.5.2.1.1	For MeSH chemicals which are being used as drugs, a MeSH heading for  
the Pharmacologic Activity (PA) must be indexed as well as the chemical entity,  
since individual chemicals are not treed under PA terms.  The MeSH record for  
each chemical shows the PA term(s) most likely to be applicable to that  
compound.  The PA term is added as a coordination;  i.e., it should be IM if the  
chemical is IM (or NIM if the chemical is NIM), and the same subheading(s)  
should be used on both terms if AQ(s) for both.  
 
			Phenobarbital in the treatment of focal epilepsy.  
				PHENOBARBITAL / * ther use 
				ANTICONVULSANTS / * ther use 
				EPILEPSY, FOCAL / * drug ther 
 

25.5.2.1.2	Prior to 1996, chemicals were treed under PA terms as well as under  
structure.  The only time an indexer needed to index a PA term in coordination  
with an individual MeSH chemical was in the rare case when the drug was not  
treed under the appropriate PA.  Thus fewer headings were required in indexing,  
but there were different indexing policies to learn for MeSH drugs versus drugs  
in the Chemical Tool (see 25.5.2.2.1), which have always required the addition  
of a PA. 
 
		In addition, the fact that a drug could be treed in numerous PA  
trees (DIAZEPAM was treed in 13 pharmacology trees) led to difficulties for  
searchers who wanted articles on only one pharmacologic activity of a given  
drug.  Each search on a drug name retrieved all citations on the drug and it was  
very difficult to eliminate unwanted retrieval.  
 
		Searching and indexing are now simplified.  Indexers use the same  
policy for all drugs, and searchers can easily retrieve a specific pharmacologic  
activity of a given drug by searching for the drug plus the specific PA term for  
the activity desired. 
 
		However, since all specific chemicals have been removed from the PA  
trees beginning in 1996, it could be very difficult for searchers to retrieve  
citations indexed in prior years (since indexers did not formerly add PA terms  
for MeSH chemicals).  If a searcher wanted articles on all drugs sharing a  
certain PA activity, a simple "Explode" command would no longer retrieve  
citations on specific drugs.  The MEDLARS Management Section is developing a new  
command for searchers to use, which will perform the same function as "Explode"  
for drug articles indexed prior to 1996.  
    

25.5.2.2	When indexing a chemical from the Chemical Tool, the indexer should  
check its HM ("Heading Mapped to");  this is the MeSH heading which will  
automatically be added to the indexing when the chemical is indexed.  If the HM  
adequately covers the chemical as discussed by the author, only the single  
chemical term needs to be indexed. 
 
			Complete amino acid sequence of Bacillus thuringiensis  
CryIA(b) protein. 
				CryIA(b) protein / * chem 
				BACILLUS THURINGIENSIS / * chem 
				AMINO ACID SEQUENCE 
				MOLECULAR SEQUENCE DATA 
				Not:  BACTERIAL PROTEINS / * chem because one of the HMs  
for CryIA(b) protein is BACTERIAL PROTEINS. 
 

25.5.2.2.1	As with MeSH headings, a PA term may be needed as a coordinate for a  
term from the Chemical Tool, if the author discusses an aspect of the compound  
which is not covered by the HM.  Again, the relevant PA should be indexed IM if  
the compound is IM (or NIM if the compound is NIM), and the same subheading(s)  
should be used on both terms if AQ(s) for both. 
 
			Oxaliplatin activity against metastatic colorectal  
adenocarcinoma. 
				oxaliplatin / * ther use 
				ANTINEOPLASTIC AGENTS / * ther use 
				COLORECTAL NEOPLASMS / * drug ther 
				ADENOCARCINOMA / * drug ther / second 
 

25.5.2.2.2	Terms in the Chemical Tool may have an additional field labeled II  
("Indexing Instructions").  IIs are similar to PAs and should be indexed instead  
of or in addition to a PA if relevant, but in most cases they are not  
pharmacologic actions.  Thus, the subheading used with the chemical may not  
apply to its II.  If an indexable II can logically take the same subheading(s)  
as the chemical for which it is a coordinate, and if the AQs are the same for  
both terms, the subheading(s) used on both terms should be the same.  
 
			Localization of pleiotrophin in the postnatal developing  
cerebellum. 
				pleiotrophin / * anal 
				NERVE TISSUE PROTEINS / * anal 
				CEREBELLUM / * chem / * growth 
			(NERVE TISSUE PROTEINS is the II for pleiotrophin) 
 
			Solubility of the opiate receptor agonist tifluadom. 
				tifluadom / * chem 
				SOLUBILITY 
				RECEPTORS, OPIOID / * agon 
				Not:  RECEPTORS, OPIOID / * chem since the article is  
not about the chemistry of the receptors but the compound that acts on them. 
			(RECEPTORS, OPIOID is the II for tifluadom) 
 
			Biosynthesis of E. coli heat-labile toxin. 
				E coli heat-labile toxin / * biosyn 
				ESCHERICHIA COLI / * metab  
			(ESCHERICHIA COLI is the II for E coli heat-labile toxin) 
 

25.5.2.3	Listed below are instructions for using PA terms with chemicals,  
whether MeSH headings or compounds from the Chemical Tool. 
 

25.5.2.3.1	Occasionally a PA may have different AQs than the chemical it is  
being coordinated with.  If the subheading used on the chemical is not an AQ for  
its PA, consult the Subheading Trees (Figure 19.5) and use the subheading treed  
above the one used on the chemical.  The same logic should also be used if the  
subheading desired is not an AQ for the chemical but is allowed on the PA.  
 
			Blood levels of the sunscreen lawsone after dermal  
administration. 
				lawsone / * blood / admin 
				SUNSCREENING AGENTS / * metab / admin 
				DRUG ADMINISTRATION, DERMAL 
 

25.5.2.3.2	Each chemical may have more than one PA.  The indexer should index  
those applicable to the article as discussed by the author (in most cases  
probably just one) no matter how many show in the record. 
 
			Use of diazepam in the treatment of anxiety. 
				DIAZEPAM / * ther use 
				ANTI-ANXIETY AGENTS, BENZODIAZEPINE / * ther use 
				ANXIETY / * drug ther 
				Not:  Any of the other PAs from the DIAZEPAM record 
 

25.5.2.3.3	Conversely, an author may discuss a new activity of a drug which  
does not appear in its PA field.  The indexer should index a MeSH heading which  
covers the PA as described by the author, even if it is not in the record for  
the term.  (If an appropriate PA is not known, the Tree in the correct category  
should be consulted;  see section 25.2.1.)  Then the new PA should be flagged so  
that it can be added to the record for the chemical.  The green Chemical Flag  
(see section 25.5.4.1) is used to flag new PAs, whether for MeSH headings or  
terms in the Chemical Tool.  This is the only exception to the rule that green  
Chemical Flags are not used for MeSH chemicals (see section 25.5.4.5). 
 
			Effects of the muscarinic agonist nebracetam on heart rate. 
				nebracetam / * pharmacol 
				MUSCARINIC AGONISTS / * pharmacol 
				HEART RATE / * drug eff  
			(Flag the new PA) 
 

25.5.2.3.4	If the author indicates the pharmacology of a drug in either the  
title or statement of purpose for the article, index that PA even if the drug's  
pharmacology is not directly relevant to the study. 
 
			Pharmacokinetics of the antidepressant adinazolam. 
				adinazolam / * pharmacokin 
				ANTIDEPRESSIVE AGENTS / * pharmacokin 
 

25.5.2.3.5	When three or more related drugs need to be grouped for the IM, make  
the group PA the IM concept, and index the specific chemicals NIM.  Similarly,  
if more than three related drugs are discussed but are not the main point of the  
article, use just their group PA and do not pick up the individual compounds at  
all. 
 
			Use of the cholinesterase inhibitors eptastigmine, tacrine,  
and velnacrine in Alzheimer's disease.  
				CHOLINESTERASE INHIBITORS / * ther use 
				eptastigmine / ther use 
				TACRINE / ther use 
				velnacrine / ther use 
				ALZHEIMER'S DISEASE / * drug ther 
 
			New drug treatments for Alzheimers' disease: a review. 
			(There is a lengthy section on the use of four cholinesterase  
inhibitors.)  
				ALZHEIMER'S DISEASE / * drug ther 
				CHOLINESTERASE INHIBITORS / ther use 
				Not:  Any of the specific drugs 
 

25.5.2.3.6	Although the policy is to use the PA as described by the author,  
frequently authors use a general activity term such as "antineoplastic agent",  
while the record for the chemical shows a more specific PA such as  
ANTINEOPLASTIC AGENTS, PHYTOGENIC.  In such cases, use the more specific PA.   
The article will still be available to searchers who explode the general term,  
but will be more precisely indexed according to MeSH policy. 
 
			Adverse effects of the antidepressant fluoxetine in the  
elderly. 
				FLUOXETINE / * adv eff 
				ANTIDEPRESSIVE AGENTS, SECOND-GENERATION / * adv eff 
				AGED (check tag) 
				HUMAN (check tag) 
 

25.5.2.3.7	Another discrepancy between author nomenclature and the use of PAs  
occurs when an author uses a structural term like "macrolide" in a clinical  
context where the pharmacologic activity is an obvious implication.  Frequently  
compounds sharing a certain chemical structure also share a pharmacologic  
activity, and clinicians know that the activity is implied when only the  
structural term is used. 
 
		Indexers should always note the treeing of any MeSH heading so that  
if pharmacologic activity seems to be implied but is not conveyed by purely  
chemical treeing, a PA term can be added.  In many cases, the annotation for  
such a term will give the existence of the related PA term available. (The  
annotation for MACROLIDES states "in ther of dis is likely to be ANTIBIOTICS,  
MACROLIDE".)  When indexing a group concept, use only the PA term, not the  
structural term. 
 
			Use of macrolides in atypical mycobacterial infections. 
				MYCOBACTERIUM INFECTIONS, ATYPICAL / * drug ther 
				ANTIBIOTICS, MACROLIDES / * ther use 
				Not:	MACROLIDES / * ther use 
 
		When indexing a specific compound given such a structural  
designation by the author, check the record for the compound and note that,  
while the compound may be treed under or have an HM of the structural term, the  
PA field has an entry of the related PA term which combines both structure and  
function.  This PA term must also be added to the indexing. 
 
			Use of the butyrophenone haloperidol in schizophrenia. 
				HALOPERIDOL / * ther use 
				ANTIPSYCHOTIC AGENTS, BUTYROPHENONE / * ther use 
				SCHIZOPHRENIA / * drug ther 
				(HALOPERIDOL is treed under the structural term  
BUTYROPHENONES) 
 

25.5.2.3.8	When indexing an enzyme inhibitor for which there is no MeSH pre- 
coordinated (ENZYME) INHIBITOR term, the PA listed will be ENZYME INHIBITORS or  
another somewhat more specific but still relatively general term like SERINE  
PROTEINASE INHIBITORS.  The indexer should add the listed PA (IM if the chemical  
is IM) but also index the specific enzyme with the subheading /antag (IM if the  
chemical and its PA are IM).  This violates the general indexing policy as  
stated in section 19.7+ of not indexing both a specific subheading and its main  
heading equivalent, but searchers need PAs for all drugs. 
 
Effects of the HMC CoA reductase inhibitor lovastatin on erythrocyte membrane  
lipid levels. 
				LOVASTATIN / * pharmacol 
				ENZYME INHIBITORS / * pharmacol 
				HMG COA REDUCTASES / * antag 
				ERYTHROCYTE MEMBRANE / * drug eff / metab 
				MEMBRANE LIPIDS / * blood 
 
		Compounds in the Chemical Tool will have an II of the specific  
enzyme/antag if the term for the enzyme is a MeSH heading;  if the enzyme is  
itself an entry in the Chemical Tool, its name will appear in the NO field and  
that is the term which should be used by the indexer. 
 
			The N-terminal sequence of the bacterial ribonuclease  
inhibitor, barstar. 
				barstar / * chem 
				ENZYME INHIBITORS / * chem 
				RIBONUCLEASES / * antag 
				AMINO ACID SEQUENCE 
				MOLECULAR SEQUENCE DATA 
 
			Effects of the endothelin-converting enzyme inhibitor  
phosphoramidon on endothelin metabolism. 
				phosphoramidon / * pharmacol 
				PROTEINASE INHIBITORS / * pharmacol 
				endothelin converting enzyme / * antag 
				ENDOTHELINS / * metab 
 
		Occasionally, the Chemical Tool enzyme is mapped (HM) to CYSTEINE  
PROTEINASES or SERINE PROTEINASES, which have pre-coordinated inhibition terms  
of CYSTEINE PROTEINASE INHIBITORS and SERINE PROTEINASE INHIBITORS,  
respectively.  In such cases, CYSTEINE (SERINE) PROTEINASE INHIBITORS is listed  
as the PA for the drug which inhibits the enzyme, but /antag cannot be used on  
the enzyme as it is not an AQ for the HM.  Rather than following the policy of  
moving up the Subheading Trees as stated in section 25.5.2.3.1, use the  
subheading /drug eff on the enzyme term. 
 
			Antagonism of prolyl endopeptidase by Z-Pro-prolinal. 
				Z-Pro-prolinal / * pharmacol 
				SERINE PROTEINASE INHIBITORS / * pharmacol 
				prolyl endopeptidase / * drug eff  
 
 

25.5.2.3.9	Compounds which act on specific receptors are indexed the same way  
as compounds which inhibit specific enzymes.  Index the listed PA which is  
general (IM if the compound is), but also add the specific receptor with /agon  
or /antag as appropriate (IM if the compound and its PA are). 
 
			Effects of bromocriptine, a D2 receptor agonist, on self  
stimulation in rats. 
				BROMOCRIPTINE / * pharmacol 
				DOPAMINE AGONISTS / * pharmacol 
				DOPAMINE D2 RECEPTORS / * agon 
				SELF STIMULATION / * drug eff 
				RATS (check tag) 
				ANIMAL (check tag) 
 

25.5.2.3.10	When indexing multidrug cancer chemotherapy, (see sections  
24.4.2.1.1 and 25.5.6.8), index the specific drugs or the protocol as given in  
the Chemical Tool but do not index the specific PAs (ANTIMETABOLITES,  
ANTINEOPLASTIC, etc.) for the components.  The only PA will be ANTINEOPLASTIC  
AGENTS, COMBINED. 
 
			Inhibition of prostate cancer growth by vinblastine and  
tamoxifen. 
				ANTINEOPLASTIC AGENTS, COMBINED / * ther use 
				VINBLASTINE / admin 
				TAMOXIFEN / admin 
				PROSTATIC NEOPLASMS / * drug ther 
				HUMAN (check tag) 
				MALE (check tag) 
				Not:  ANTINEOPLASTIC AGENTS, HORMONAL / admin 
				Not:  ANTINEOPLASTIC AGENTS, PHYTOGENIC / admin even  
though these are the listed PAs for the two drugs. 
 
			Treatment of Hodgkin's disease with the MOPP protocol. 
				MOPP protocol / admin 
				ANTINEOPLASTIC AGENTS, COMBINED / * ther use 
				HODGKIN'S DISEASE / * drug ther 
				Not:  ANTINEOPLASTIC AGENTS, PHYTOGENIC even though that  
is the PA for VINCRISTINE, one of the components of the protocol, etc. 
 
 

25.5.2.4	Many PA terms will be related to other PA terms;  for example, a  
particular mechanism at a given receptor may result in a pharmacologic effect.   
The record for the PA will have an FX to the other related PA.  Indexers should  
always look for FXs in records as well as PAs.  For example, the record for  
SEROTONIN UPTAKE INHIBITORS has an FX of ANTIDEPRESSIVE AGENTS, SECOND- 
GENERATION because many serotonin uptake inhibitors act as antidepressants.  
 

25.5.3		The instructions listed below summarize the indexing of  
cjemicals from MeSH or the Chemical Tool. 
 
When indexing a chemical, the steps to be taken are as follows: 
 
1.	Look it up in MeSH, and use it if there. 
 
2.	If the chemical is in MeSH and is discussed in the article as having  
pharmacological   activity, add the appropriate PA term as discussed in the  
article (whether or not the record in MeSH lists that particular PA).  The PA  
should be made IM if the chemical is, and the same subheading(s) should be used  
on both if AQs for both. 
 
3.	If the chemical is not in MeSH, look in the Chemical Tool. 
 
4.	If the chemical is in the Chemical Tool, add any appropriate PA or II term  
as discussed in the article (whether or not the record  in the Chemical Tool  
lists that particular PA or II). The PA or II should be made IM if the chemical  
is an IM concept, and the same subheading(s) should be used on both the chemical  
and its PA if AQs for both.  The same subheading should be used on the II if  
logical and if an AQ. 
 
5.	For chemicals in the Chemical Tool, SYs may be typed instead of NMs (just  
as X-references may be typed instead of MHs for MeSH headings). However, unlike  
MeSH headings and X-references, NMs or SYs may not be used if more than 36  
characters; use a shorter NM or SY instead.  If the record does not contain a  
short NM or SY, flag for the chemists  to add one. 
 
6.	RNs may not be used instead of NMs or SYs for chemicals in the Chemical  
Tool. 
 
The "sort" (how entries are put in order alphabetically, etc.) is different for  
the Chemical Tool than for MeSH, so indexers need to know two sets of rules in  
order to be able to find chemicals in both places. In sections 25.5.3.1 to  
25.5.3.7, the differences in the "sort" are compared. 
 

25.5.3.1	In MeSH, alphabetization is by the shortest word first; in the  
Chemical Tool, alphabetization is letter-by-letter. 
 
MeSH			Chemical Tool 
 
		METHYL VIOLOGEN				methylmethacrylate 
		METHYLADENINE RECEPTORS 		methyl methanesulfothioate	 
	 
 

25.5.3.2	In MeSH, hyphenated words are alphabetized as if they are all one  
word; in the Chemical Tool, hyphenated words are alphabetized letter-by-letter.  
(In other words, the publications treat hyphenated words the same way.) 
 
 
		MeSH 			Chemical Tool 
ISOBUTYLCYANOACRYLATE			4-aminophenyl-beta-galactoside 
3-ISOBUTYL-1-METHYLXANTHINE			aminophenylboronic acid			 
		 
 

25.5.3.3	In both publications, number prefixes are ignored. See examples  
above. 
 

25.5.3.4	In both publications, most single-letter prefixes are ignored, but  
if the complete word is spelled out, it is alphabetized at the word. 
 
		MeSH			Chemical Tool 
	BROMCRESOL PURPLE		acetamide amidohydrolase 
	P-BROMDYLAMINE			p-acetamidobenzoic acid 
	BROMELAINS			acetanilide hydroxylase 
 
	PAPUA NEW GUINEA		PAPS sulfotransferase 
	PARA-AMINOAZOBENZENE		para-acetamidobenzoic acid 
 

25.5.3.5	In both publications, single letters may be read under some  
circumstances. If a term containing a single letter cannot be found when the  
letter is ignored, look for it as if the letter were read and vice versa. 
 
		MeSH			Chemical Tool 
	(letter ignored)		(letter ignored) 
	 LYMPHOCYTES		hemoglobin Bart's 
	 B-LYMPHOCYTES		hemoglobin M Boston 
	 T-LYMPHOCYTES		hemoglobin A, carbamylated 
	 LYMPHOCYTIC CHORIOMENINGITIS 
				 
MeSH				Chemical Tool 
(letter read)		(letter read) 
SZONDI TEST		tazobactam 
 
T-CELLS			t-butanol 
 
TABES DORSALIS		TCAOB 
 
 
 

25.5.3.6	In MeSH, combinations of letters and numbers precede longer words  
 
beginning with the same letters; in the Chemical Tool, such combinations follow  
longer words beginning with the same letters. 
 
MeSH			Chemical Tool  
	A-23187				gyromitrin  
	ABATE				G 130  
					Ha antigen  
	RO 20-1724 335			squaric acid dibutyl ester  
	ROBENIDINE			SQ-10996  
					SR gene product 
 

25.5.3.7	In MeSH, numbers are in numerical order; in the Chemical Tool,  
numbers are in numerical order digit-by-digit, not by the whole number. 
 
		MeSH			Chemical Tool 
		RO 7-0207		MK 196  
		RO 7-0582		MK-2  
		RO 10-9359		MK 302 
					MK 571 
					MK 7 
 

25.5.4		When an indexer determines that a chemical needs to be  
indexed, but it cannot be found in either MeSH or the Chemical Tool, it must be  
flagged to the attention of the Chemical Specialists so that a record can be  
created for it in the Supplementary Chemical Records file and the compound can  
be added to the article. 
 

25.5.4.1	Fill out the Chemical Flag as follows (see Figure 25.5.4): 
 
a. Indexer: Supply indexer number on all flags. 
 
b.	Chemical: Supply enough information for the Chemical Specialists to know  
exactly which compound is to be indexed. 
 
	(1). If the chemical is the only compound in the title of the  article,  
"Title cpd" is 			sufficient. If more than one chemical is in the  
title, or when flagging a compound not in  		the title, use the rules  
in (2) or (3). 
 
	(2). If the chemical has a short name, write the complete name. 
 
	(3). If the chemical has a long name, write as much as needed to identify  
it and to 			differentiate it from any other chemicals on the same  
page (for example, "5-phenyl..." if 		no other chemical on the same  
page begins that way,  
"5-phenyl-6-hydroxy..." if another chemical begins  
"5-phenyl-3-hydroxy", etc.) 
 
c.	Page: This is the page where the most complete description of the chemical  
is located (not necessarily the first page of the article or the page on which  
the name of the chemical first appears). Pencil a small asterisk or arrow where  
the description is found, and paperclip the flag on the facing page. 
 
d.	Needed as IM with / *: If the chemical is an IM concept, indicate the  
subheading needed IM here. The 2-letter subheading abbreviations may be used,  
but write them distinctly; the Chemical Specialists often have trouble  
determining if the subheading needed is "bi" or "bl", "ch" or "cl", "ae" or  
"ai", etc.  
 
If the chemical is an IM concept but no subheading is to be used IM (very rare),  
put a zero or write "none" in this section. 
 
e.	NIM with /: If the chemical is an NIM concept, or is an IM concept but  
needs additional NIM subheadings, indicate any NIM subheadings here. Again, be  
sure to write distinctly if using a 2-letter abbreviation.  
 
If the chemical is an NIM concept but no subheading is to be used with it (as,  
for example, a reagent), put a zero or write "none" in this section.  
 
f, g.	Pharmacological Action (PA): or Indexing Instruction (II): If the chemical  
is being used as a drug or has a physiological action in the article, index the  
appropriate PA or II term, using the subheadings indicated for the chemical  
itself, if applicable (see 25.5.2.2.1 and 25.5.2.2.2). Then indicate the PA or  
II used on these lines. Also indicate any other possible PAs or IIs listed by  
the author but not indexed as not being relevant to the article. 
 
h, i, j.	New data available: If the chemical is already in the Chemical Tool  
but new information about it is given in the article, or if the chemical is a  
MeSH heading but the PA needed for the article is not listed in its record,  
index the chemical and any applicable PA (or II if it is a Chemical Tool Term).  
Then fill out a chemical flag briefly so that the new information in this  
article can be added to the record for the chemical. Put the name of the  
chemical on line (b) so the Chemical Specialists know which chemical is being  
flagged, then check the appropriate box for the new data and write enough  
information on the flag so that the Specialists will know exactly what new  
information is to be added to the record.  
 
k.	Comment: This field is rarely needed, but sometimes it is helpful to write  
a comment to the Chemical Specialists, (for example, alerting them to another  
compound with a similar name). When indexing a foreign-language journal, use  
this field to give the Chemical Specialists any information which would help  
them if they cannot read the language (for example, "Structure given on p. 13",  
or "See ref 14", etc.). 
 
 
Figure 25.5.4 
 
 

25.5.4.2	After flagging the chemical, the indexer must index any relevant PA  
or II, making it IM if the compound is and using all subheadings desired with  
the flagged compound if the subheadings are AQs and if the subheadings apply  
(see 25.5.2.2.1 and 25.5.2.2.2). 
 
The indexer must not attempt to index the chemical structure of the flagged  
compound; that is the job of the Chemical Specialist who processes the flag. If  
the indexer adds a chemical structure term to the article in an attempt to index  
the flagged compound, the Chemical Specialist does not know whether the term has  
been added for some other reason, and will not remove it, even if the compound  
ends up being mapped to a different chemical. 
 
Blood levels of a new antineoplastic ammonium compound, XYZ-123, when used in  
the treatment of experimental mammary neoplasms in mice. 
(XYZ-123 is not in MeSH or the Chemical Tool and is flagged to be added to the  
article with a PA of ANTINEOPLASTIC AGENTS and the subheadings / * blood and /  
ther use) 
ANTINEOPLASTIC AGENTS / * blood / ther use 
MAMMARY NEOPLASMS, EXPERIMENTAL / * drug ther 
MICE (check tag) 
ANIMAL (check tag) 
FEMALE (check tag) 
(Not: AMMONIUM COMPOUNDS/ * blood/ ther  use) 
(The Chemical Specialist will index the chemical aspect) 
 

25.5.4.3	Only one compound may be entered on each Chemical Flag. If two  
related compounds (for example, two antibiotics with the same group name, but A  
and B) need to be flagged, both may be entered on one flag if they are both IM  
or NIM and if they are to be indexed with the same subheading(s), but a blank  
flag should be inserted behind the single flag so that there are two flags for  
the two compounds. 
 
When a flaggable compound appears in a series of articles, a separate flag  
should be used for each article, because it is highly unlikely that the compound  
will need the same subheadings in all the articles; however, the indexer need  
not repeat information on subsequent flags (for example, the PA) if the chemists  
do not need the information to process the article. 
 

25.5.4.4	Do not use the green Chemical Flag to request a new MeSH heading for  
a group of chemicals (either a structural grouping or an action group). These  
flags are to be used only for individual chemicals which need to be indexed in  
an article but are not available in MeSH or the Chemical Tool; terms created by  
the Chemical Specialists in response to the green flags appear only in the  
Supplementary Chemical Records file, not in MeSH.  
 
If an indexer would like MeSH to create a new term to cover a group of  
chemicals, the correct form to be used is the REQUEST FOR NEW MeSH TERM form.  
 

25.5.4.5	The green Chemical Flag may be used to request a new PA for an  
existing MeSH heading. This is the only time the Chemical Flag may be used for  
MeSH heading. 
 
Use the REQUEST FOR CHANGE TO EXISTING MeSH TERM form to let MeSH know of any  
change needed in a chemical term (singular or plural, structural or activity  
term) which already exists in MeSH (for example, that the term should be treed  
differently). The green Chemical Flag is not to be used for this purpose either. 
 

25.5.5		Occasionally, an indexer finds a term in MeSH which looks  
similar to the compound to be indexed, but if it is not identical the indexer  
may wonder whether to use that MeSH term or to check the Chemical Tool and/or  
flag the compound. Sections 25.5.5.1 to 25.5.5.3 list the situations in which  
the MeSH term may be used.	 
 

25.5.5.1	The initial letters d,l, dl, R or S and the symbols + or - may be  
ignored. 
 
d-propranolol = PROPRANOLOL 
 
The letters listed above refer to stereoisomers (molecules which have the same  
molecular structure but a different spatial arrangement). If the article  
especially discusses the stereoisomers, the term STEREOISOMERS may be added (NIM  
with no subheading).  
 
Effects of (S)- and (R)- isomers of the antiarrhythmic propafenone on the  
activity of cytochrome P-450. 
PROPAFENONE / * pharmacol 
ANTI-ARRHYTHMIA AGENTS / * pharmacol 
CYTOCHROME P-450 / * drug eff 
STEREOISOMERS 
 

25.5.5.2	The salts sodium (Na), potassium (K), hydrochloride (HCl) and  
sulfate (SO4) may be ignored for organic compounds, but esters must be  
considered as separate compounds. 
 
Ampicillin sodium = AMPICILLIN 
Fluphenazine decanoate must not be indexed as FLUPHENAZINE; look  it up in the  
Chemical Tool. 
 

25.5.5.3	The singular suffix -IC ACID may be used interchangeably with-ATE  
(and  -IC ACIDS may be  interchanged with -ATES, but a plural term must never be  
used for a singular concept and vice versa. 
 
"Iodohippurate" may be indexed as  IODOHIPPURIC ACID. 
"Hydroxybutyric acids" may be indexed as HYDROXYBUTYRATES. 
"Acetate" or "acetic acid" must not be indexed as ACETATES; look it up in the  
Chemical Tool.  
 
 
 

25.5.6	Specific instructions are given below on when to flag various  
other types of compounds encountered in the biomedical literature.  
 

25.5.6.1	A peptide, protein, gene product, or biological "factor", even when  
given a specific name in the article, should usually be flagged only if its full  
amino acid sequence is given.  If the sequence is not given but something in the  
article indicates that it has been determined previously, mark this information  
with an arrow in the text and flag the compound.  Be careful to distinguish  
between a gene and the protein or gene product it encodes;  the protein or gene  
product should be flagged, but if the article is merely about the gene, no  
chemical flag should be submitted. 
 
If an article discusses a protein but does not state that its sequence has been  
determined, index only the group term(s) for the protein (GLYCOPROTEINS,  
BACTERIAL PROTEINS, etc.). 
 
Immunology of rotavirus outer coat proteins VP3 and VP9. 
(No sequence information given or discussed) 
rotavirus VP3 protein / * immunol 
ROTAVIRUS / * immunol 
VIRAL COAT PROTEINS / * immunol 
(Rotavirus VP3 protein is in the Chemical Tool, so it can be indexed.  Rotavirus  
VP9 protein is not in the Chemical Tool;  since no sequence information is  
given, it should not be flagged but merely indexed as VIRAL COAT PROTEINS.)  
  
There are two exceptions to the rule stated above: 
 
1. Flag a disease-related protein, gene product, peptide, or other biological  
"factor" such as a tumor marker if a molecular weight is given for it, even  
though no indication of amino acid sequence is given.  (It must be related to a  
disease, not just a disease-causing organism.) 
 
2. Flag any HIV- or HIV-infection-related protein, gene product, peptide, or  
biological "factor" even if it has not been isolated or purified and no  
molecular weight or amino acid sequence information is given for it.  
 

25.5.6.2	An antigen should be flagged under the same conditions as those  
given for proteins in 25.5.6.1.  Most antigens are proteins, but many are  
carbohydrates;  for carbohydrates a complete carbohydrate sequence must have  
been determined. 
 
Unless the antigen has been sequenced, it should be indexed only with the  
appropriate group term in MeSH (ANTIGENS, VIRAL, etc.).The same exceptions apply  
for disease-related and HIV-related antigens as apply for proteins and other  
biological "factors". 
 
Do not flag blood group antigens. 
 

25.5.6.3	No proof of isolation or amino acid sequence is necessary to flag a  
receptor. Any article in which the author discusses a receptor for a particular  
compound should be flagged if the term for the receptor is not already available  
in MeSH or the Chemical Tool. However, the author must indicate that there is a  
specific cell surface molecule which is acting as the receptor; do not flag a  
"binding site" if it is not clear from the article that a specific molecule is  
involved (merely index BINDING SITES), and do not flag an article on the binding  
process irrespective of a specific site.  
 

25.5.6.4	An enzyme should be flagged if it has been isolated and a defined  
reaction is catalyzed; no proof of amino acid sequence or molecular weight  
determination is needed, even though enzymes are proteins. 
 

25.5.6.5	A recombinant protein should not be flagged, but merely indexed as  
the specific protein (IM), coordinated with RECOMBINANT PROTEINS (NIM, with the  
same subheading(s) if allowable). 
 
Recombinant interleukin-1 induces heat-shock proteins. 
INTERLEUKIN-1 / * pharmacol 
RECOMBINANT PROTEINS / pharmacol 
HEAT-SHOCK PROTEINS / * drug eff / biosyn 
 
If the article gives a new generic or trade name for the recombinant protein,  
flag it for the Chemical Specialists but index in the same manner as above even  
though flagged; indicate on the flag that the protein has been indexed. The  
Chemical Specialists and MeSH will use the information from flags to determine  
when a new term should be created for an especially important recombinant  
protein (such as INTERFERON-GAMMA, RECOMBINANT). 
 

25.5.6.6	A monoclonal antibody, even if given a name, should in general be  
indexed only as ANTIBODIES, MONOCLONAL. Flag a monoclonal antibody only if the  
article states that it is available commercially or undergoing clinical trials,  
and that it is being used diagnostically or therapeutically, and that it has  
been given a generic or trade name. 
 

25.5.6.7	An alloy should be flagged if it contains three or fewer metals. If  
an alloy contains more than 3 metals, flag it only if it has been given a  
specific name and is used for anything other than a dental alloy (such as a  
surgical implant, biocompatible material, etc.). If an alloy has not been given  
a name and contains more than 3 metals, index it only with the appropriate alloy  
term available in MeSH, such as NICKEL-CHROMIUM ALLOYS, DENTAL ALLOYS, etc.  
 

25.5.6.8	Antineoplastic agents are often administered in combination with  
other anticancer drugs which have a different mechanism of action, producing a  
better response than if a single drug were given. Such combinations of  
antineoplastic drugs are called "protocols"; the drugs do not have to be  
administered at the same time to constitute a protocol. Protocols are usually  
named by acronyms composed of the first letters of the drugs used, but the  
derivation may not be readily apparent because the researchers may use the first  
letter of the trade name in the protocol name, and call the drug by its generic  
name in the article. (For example, a drug commonly used in cancer protocols is  
DOXORUBICIN, but the letter in most protocols is A, for Adriamycin, its trade  
name.)  
 
Anticancer protocols are available in the Chemical Tool. When an article  
discusses such a protocol, index the term ANTINEOPLASTIC AGENTS, COMBINED / ther  
use (IM or NIM, depending on whether or not the protocol is the main point of  
the article). Then check the Chemical Tool for the name of the protocol, and  
index it with the subheading /administration & dosage (always NIM) if available.  
If it is not in the Chemical Tool, index ANTINEOPLASTIC AGENTS, COMBINED / ther  
use (IM or NIM) and flag the protocol for the Chemical Specialists, indicating  
its subheading to be /admin (NIM), and its PA to be ANTINEOPLASTIC AGENTS,  
COMBINED.  (NOTE! These rules on subheadings apply to the most common studies we  
index, where the main point is the therapeutic use of the protocol. It is always  
acceptable to use other subheadings when indexing a study on a different aspect  
of a protocol such as its pharmakokinetics.) 
 
Because protocol names are usually comprised of the first letters of the drugs  
included in them, it is possible for two different protocols to be given the  
same name by different researchers. Be sure to verify the drugs included in any  
protocol found in the Chemical Tool; flag any new protocol given the same name  
but composed of different drugs. 
 
Treatment of ovarian neoplasms with CAP (cyclophosphamide, doxorubicin and  
cisplatin). 
OVARIAN NEOPLASMS / * drug ther 
ANTINEOPLASTIC AGENTS, COMBINED / * ther use 
CAP-regimen 1 / admin 
HUMAN (check tag) 
FEMALE (check tag) 
(Not: CAP combination or CAP protocol 1, both of which are also in the Chemical  
Tool but are composed of different drugs) 
 

25.5.6.9	Occasionally, drug manufacturers combine two or more drugs into one  
dosage form. If the combination has a trade name, the Chemical Specialists will  
enter it into the Supplementary Chemical Records file, so look in the Chemical  
Tool for all such trade-named combinations and flag if not available. 
 
 

25.5.7	When an article is about a group of structurally-related  
chemicals, the indexer should merely index the best MeSH group term available,  
because group terms are not added to the Chemical Tool. If, however, the indexer  
is unsure of the indexing, the group concept may be flagged with the green  
Chemical Flag as long as the indexer states that the Chemical Specialists merely  
need to supply the correct MeSH term to cover the group concept. A statement in  
the Comment field such as "Unsure of best MeSH term" is sufficient. 
 

25.5.7.1	Before flagging a group concept, however, the indexer should try to  
determine a MeSH term from clues in the article. For example, the indexer might  
not know what heading to use for an article entitled "Synthesis of  
indanediones". However, the introduction states that the compounds methindione  
and chlorophacinone  have been studied and the authors are synthesizing 20  
similar compounds. By looking at the records for methindione and chlorophacinone  
in the Chemical Tool, the indexer can determine that both are INDANS (the HM for  
both) and that this is thus the correct MeSH heading to use to cover the group  
concept. 
 

25.5.7.2	In addition, before flagging a group concept the indexer should be  
sure that a group term is actually needed; it may well be that the article  
really is about only two or three specific compounds. The Chemical Specialists  
will add up to three specific related terms to the Chemical Tool per article.  
Since the indexing "Rule of Three" permits the indexing of up to three related  
terms (if there is not too much depth and all three are discussed), two or three  
specific compounds should be flagged individually, even if a group concept  
appears in the title. (Of course, it is still possible that a general MeSH  
heading may be needed to group these individual compounds for the IM.) 
 

25.5.8	The subheading /analogs & derivatives is available in MeSH but  
has a very restricted use by indexers--only for articles on groups of analogues,  
since any specific analogue must be flagged if not available in MeSH or the  
Chemical Tool. The Chemical Specialists, however, use /analogs & derivatives  
frequently because the HM for any term in the Chemical Tool is either a plural  
MeSH term (such as PYRIDINES) or a singular MeSH term with the subheading  
/analogs & derivatives. 
 

25.5.8.1	The subheading /analogs & derivatives is not permitted with any term  
from the Chemical Tool, because each is mapped to a plural term or as an  
analogue already. Thus, any article on a group of structural analogues of a term  
from the Chemical Tool may be indexed using just the term. 
 
Synthesis of analogs of efaroxan. 
efaroxan / * chem syn 
(The HMs for efaroxan are BENZOFURANS and IMIDAZOLES, so this article will print  
in Index Medicus at BENZOFURANS / chem syn and IMIDAZOLES / chem syn)  
 

25.6		The PA terms in MeSH (usually referred to as the Pharmacologic  
Activity terms although also used for physiologic activity concepts), group  
compounds which share the same activity.  MeSH contains all the major action  
groups in pharmacology and physiology. Examples of PA terms include  
ANTIHYPERTENSIVE AGENTS, ANTIBIOTICS, ANTINEOPLASTIC AGENTS, BACTERIAL PROTEINS,  
ENZYMES, etc. 
 
The following are some general observations about indexing policy regarding PA  
terms. 
 

25.6.1	Do not index a PA term with /analogs & derivatives.  This  
subheading cannot be used with group concepts.  In addition, "analogues" are  
structurally related compounds, while PA terms refer to activity. 
 

25.6.2	Index a PA term with /pharmacology when an article is about  
the pharmacology of the group of compounds sharing that activity. 
 
Effects of cholinesterase inhibitors on heart rate. 
	CHOLINESTERASE INHIBITORS / * pharmacol 
	HEART RATE / * drug eff 
	 

25.6.3	In addition, index a PA term with /pharmacology when an  
article is about the pharmacology of a MeSH compound with that PA activity but  
not treed under it, or the pharmacology of a Chemical Tool term having that PA  
activity.  In these cases, the PA term is used as a coordinate and is always  
indexed IM if the compound is, using the same subheading(s) on the PA as on the  
compound, if possible (see 25.5.2.1.1 and 25.5.2.2.1). 
 
Effects of the MAO inhibitor pargyline on heart rate. 
PARGYLINE  / * pharmacol 
MONOAMINE OXIDASE INHIBITORS  / * pharmacol 
HEART RATE / * drug eff 
 
Is OK-432 a biological response modifier? 
OK-432 / * pharmacol 
BIOLOGICAL RESPONSE MODIFIERS / * pharmacol 
 
Effects of the antidepressant drug adinazolam on liver function. 
adinazolam / * pharmacol 
ANTIDEPRESSIVE AGENTS / * pharmacol 
LIVER / * drug eff 
 
 

25.7		For many PA terms in MeSH, there is a corresponding process or  
disease term available also; examples include ANESTHETICS and ANESTHESIA,  
ANTIDEPRESSIVE AGENTS and DEPRESSION, IMMUNOSUPPRESSIVE AGENTS and  
IMMUNOSUPPRESSION or IMMUNOSUPPRESSION (PHYSIOLOGY), etc. 
 
The choice of heading depends upon the slant of the article; the author may  
discuss only the drug group, only the process or disease, or both the drug group  
and the process or disease. 
 
Therapeutic use of antihypertensive agents. 
ANTIHYPERTENSIVE AGENTS / * ther use 
 
Drug therapy of hypertension. 
HYPERTENSION / * drug ther 
 
Use of the most common antihypertensive agents in hypertension. 
ANTIHYPERTENSIVE AGENTS / * ther use 
HYPERTENSION / * drug ther 
 

25.8		When indexing a drug or chemical with the subheading /pharmacology,  
the usual coordination is an organ, organism, physiological or psychological  
process with the subheading /drug effects. 
 
The effect of non-steroidal anti-inflammatory agents on the liver. 
ANTI-INFLAMMATORY AGENTS, NON-STEROIDAL / * pharmacol 
LIVER / * drug eff 
 
The effect of the stimulant methylphenidate on short-term memory. 
METHYLPHENIDATE / * pharmacol 
CENTRAL NERVOUS SYSTEM STIMULANTS / * pharmacol 
MEMORY, SHORT-TERM / * drug eff 
 

25.8.1	If the drug affects a specific aspect of an organ or organism,  
that aspect should be indexed also, but will probably be an NIM concept in  
articles where the pharmacology is the main point. 
 
The effect of NSAIDs on liver cytology. 
NSAID / * pharmacol 
LIVER / * drug eff / cytol 
 
The effect of erythromycin on metabolism in Streptococcus pyogenes. 
ERYTHROMYCIN / * pharmacol 
ANTIBIOTICS, MACROLIDE / * pharmacol 
STREPTOCOCCUS PYOGENES / * drug eff / metab 
 
In the examples given above, if the cytology of the liver or metabolism in  
Streptococcus pyogenes were as important as the effects of the drug, both  
subheadings could be made IM, following the rules given in section 19.6.1. 
 
 

25.8.2	When an article is about the effects of an exogenous drug on  
some physiological function which can be expressed as a subheading, it must be  
remembered that the subheading on the drug is /pharmacology, not that  
physiologic subheading. In the following examples, note the use of /pharmacology  
versus the correct use of the physiologic subheading on the drug. 
 
Effects of the gout suppressant allopurinol on liver metabolism. 
ALLOPURINOL / * pharmacol 
GOUT SUPPRESSANTS / * pharmacol 
LIVER / * drug eff / metab 
(Not: ALLOPURINOL / * metab) 
 
Metabolism of the gout suppressant allopurinol in the liver. 
ALLOPURINOL / * metab 
GOUT SUPPRESSANTS / * metab 
LIVER / * metab 
 
Immunopharmacology of the immunosuppressant azathioprine. 
(Author studies the effects of azathioprine on cellular immunity) 
AZATHIOPRINE  / * pharmacol 
IMMUNOSUPPRESSIVE AGENTS / * pharmacol 
IMMUNITY, CELLULAR / * drug eff 
(Not: AZATHIOPRINE  / * immunol) 
 
Production of an anti-azathioprine antibody. 
AZATHIOPRINE  / * immunol 
* ANTIBODY FORMATION  
(Here the drug is acting as an antigen) 
 

25.9		Many compounds in MeSH are endogenous substances for which the  
subheading /physiology is an AQ; however, they may also be given as exogenous  
drugs.  It can be difficult to determine whether a given article is about the  
physiologic role or pharmacology of such a compound, but the indexer must make  
the distinction depending upon the slant of the article. 
 
Effects of epinephrine on blood pressure.  
(Author discusses the use of epinephrine as a vasoconstrictor agent used in with  
anesthesia, and how it can affect blood pressure during surgery) 
EPINEPHRINE / * pharmacol 
VASOCONSTRICTOR AGENTS / * pharmacol 
BLOOD PRESSURE / * drug eff 
 
The physiological role of epinephrine in maintaining blood pressure. 
EPINEPHRINE / * physiol 
BLOOD PRESSURE / * physiol 
 

25.9.1	As stated in 19.8.55 and 25.8.2, an article about the effects  
of an exogenous drug on a physiological process is indexed as the /pharmacology  
of the drug, not /physiology even if /physiology is an AQ for the drug. The  
subheading /physiology is to be used only for an article on the role of an  
endogenous compound. 
 

25.10		Although /pharmacology is usually the correct subheading to cover  
"effects of" an exogenous drug, /therapeutic use is better when the main point  
of the article is merely to determine if the drug has therapeutic effects. 
 
The effect of rifampin on tuberculosis in rats. 
RIFAMPIN  / * ther use 
ANTIBIOTICS, ANTITUBERCULAR / * ther use 
TUBERCULOSIS / * drug ther 
RATS (check tag) 
ANIMAL (check tag) 
 

25.10.1	It is possible, however, for an article to be about the effect of a  
drug on a specific aspect of a disease and not about the treatment of the  
disease with the drug; in these cases, the correct subheading to use on the drug  
is /pharmacology, not /therapeutic use. 
 
Effects of immunosuppressive agents on T-lymphocytes in patients with chronic  
kidney failure being prepared for transplantation. 
IMMUNOSUPPRESSIVE AGENTS / * pharmacol 
T-LYMPHOCYTES / * drug eff 
KIDNEY FAILURE, CHRONIC / * immunol / surg 
(Not: IMMUNOSUPPRESSIVE AGENTS / * ther use) 
(Not: KIDNEY FAILURE, CHRONIC / * drug ther) 
 
Effects of the beta-blocker propranolol on heart rate in obese patients. 
PROPRANOLOL / *  pharmacol 
ADRENERGIC BETA-ANTAGONISTS / * pharmacol 
HEART RATE / * drug eff 
OBESITY / * physiopathol 
(Not: PROPRANOLOL / * ther use) 
(Not: OBESITY / * drug ther) 
 

25.11		The injurious effects of a chemical are indexed as /adverse effects,  
/toxicity, or /poisoning; see section 19.9 for a comparison of these  
subheadings. 
 

25.11.1	When a drug or chemical causes a harmful effect, the subheading used  
on the disease produced is /chemically induced. 
 
NSAID-induced gastric ulcer in the elderly. 
NSAID / * adv eff 
STOMACH ULCER / * chem ind 
 
 

25.11.2	In research, a chemical known to have harmful effects on an organ  
may be used to induce a disease of that organ in order to study some aspect of  
the disease; the chemical and the induction of the disease are not the main  
points of the article but merely the research technique. In such a case, index  
the experimental disease with the subheading appropriate to the study as the IM  
concept. Index the disease NIM with the subheading /chemically induced, and add  
the chemical NIM but do not use a subheading on it (since the study is not about  
the drug's adverse effects, nor poisoning by it, nor a study to see if it is  
toxic). 
 
Lung transplantation as an effective treatment of methylcholanthrene induced  
lung cancers in rats. 
* LUNG TRANSPLANTATION 
LUNG NEOPLASMS / * surg / chem ind 
METHYLCHOLANTHRENE 
CARCINOGENS 
RATS (check tag) 
ANIMAL (check tag) 
 
In many instances, the induction of the disease by the chemical is  merely the  
research tool and quite incidental to the material of the article. In these  
cases, the chemical is third-tier and need not be indexed at all, nor does  
/chemically induced have to be added to the disease concept. 
 

25.11.3	Do not confuse experimental studies where a chemical is used  
deliberately to induce a disease in order to study some aspect of the disease  
with those in which the toxicity of the drug itself is the point. 
 
Does methylcholanthrene induce LUNG cancers in rats? 
METHYLCHOLANTHRENE / * tox 
CARCINOGENS / * tox 
LUNG NEOPLASMS / * chem ind 
RATS (check tag) 
ANIMAL (check tag) 
 

25.11.4	Many articles on poisoning by a drug or chemical discuss some aspect  
of the poisoning; in these articles, the subheading needed may be used with the  
MeSH heading POISONING, but it must be made NIM in reference to poisoning by a  
specific drug (see section 19.7.4). 
 
Treatment of barbiturate poisoning. 
BARBITURATES / * pois 
POISONING / ther    
 

25.12		Indexers sometimes have difficulty deciding whether to use  
/therapeutic use or /administration & dosage with a drug. Usually the point of  
the article is whether the drug is an effective treatment, so /therapeutic use  
is more likely to be the correct subheading. The subheading /administration &  
dosage should be saved for articles in which how to administer the drug is the  
main point (how much to give, how often to give it, by what route, etc.). 
 
Vancomycin administration for staphylococcal endocarditis. 
VANCOMYCIN  / * ther use 
ANTIBIOTICS, GLYCOPEPTIDE / * ther use 
ENDOCARDITIS, BACTERIAL / * drug ther / microbiol 
STAPHYLOCOCCAL INFECTIONS / * drug ther 
 
Short-term vancomycin administration versus the standard 28-day schedule. 
VANCOMYCIN / * admin 
ANTIBIOTICS, GLYCOPEPTIDE / * admin 
DRUG ADMINISTRATION SCHEDULE 
 

25.12.1	Since /administration & dosage is treed under /therapeutic use in  
the Subheading Trees (see Figure 19.5), administration routes and/or dosage  
forms may be added as NIM coordinations for drugs which have been indexed with  
/therapeutic use; it is not necessary to use /administration & dosage also.  
 
Use of albuterol in the treatment of asthma.  
(A section contains a discussion on oral versus inhalation administration)   
ALBUTEROL / * ther use 
BRONCHODILATOR AGENTS / * ther use 
ASTHMA / * drug ther 
ADMINSTRATION, ORAL 
ADMINISTRATION, INHALATION 
 

25.12.2	When the route of administration or dosage form is indexed for a  
drug, avoid using subheadings with the dosage form or route, because the  
subheading in question usually applies to the drug itself. 
 
Adverse effects of intramuscular penicillin G. 
PENICILLIN G / * adv eff / admin 
PENICILLINS / * adv eff / admin 
INJECTIONS, INTRAMUSCULAR 
(Not: INJECTIONS, INTRAMUSCULAR / adv eff) 
 
Poisoning with aspirin tablets. 
ASPIRIN / * pois / admin 
TABLETS 
(Not: TABLETS / pois) 
 
But: Pain associated with intravenous injections of vinblastine. 
(Article discusses how intravenous injections of various types of drugs can be  
painful) 
VINBLASTINE / * adv eff / admin 
ANTINEOPLASTIC AGENTS, PHYTOGENIC / * adv eff / admin 
INJECTIONS, INTRAVENOUS / * adv eff 
PAIN / * etiol    
 

25.13		Indexers must frequently distinguish between the /analysis,  
/chemistry, /isolation & purification, /metabolism, and /pharmacokinetics of  
chemical compounds.  For a comparison of these subheadings, see section 19.10. 
 

25.13.1	One aspect of /anal encountered frequently is HISTOCYTOCHEMISTRY,  
which refers to the identification of chemical compounds present in tissue  
slices using stains or other methods which allow them to be seen in their  
location in the tissue, rather than being extracted.  When indexing  
HISTOCYTOCHEMISTRY or its indentions, the subheading on the chemical is /anal,  
and the corresponding subheading on the organ is /chem;  since /chem is not an  
AQ for diseases, the subheading on any disease studied should be /metab (except  
for neoplasm terms from Category C4, for which /chem is an AQ). 
 
Although histochemistry articles will almost always have pictures of the tissue  
showing the location of the chemicals, if the author is concerned only with  
chemical content rather than tissue structure, /anatomy & histology, /cytology,  
/pathology or /ultrastructure need not be added. 
 
Histochemical determination of serotonin in the liver in cirrhosis and liver  
neoplasms. 
SEROTONIN / * anal 
LIVER / * chem 
LIVER CIRRHOSIS / * metab 
LIVER NEOPLASMS / * chem 
HISTOCYTOCHEMISTRY 
 

25.13.2	If an article discusses how a disease causes changes in the levels  
of the compounds studied, then /metab is the correct subheading to use on the  
compound and the organ as well as the disease, rather than /anal and /chem.   
(See sections 19.10.1 and 19.10.4.)  
 

25.13.3	HISTOCYTOCHEMISTRY and its indentions can also be used by  
pathologists to characterize tissue, since many compounds are present only in  
certain types of tissues or cells.  In such studies, /pathol may be the only  
subheading needed on the tissue and disease (although /anal will still, of  
course, be needed on the chemical.) 
 

25.13.4	HISTOCYTOCHEMISTRY and its indentions can be used to demonstrate the  
presence of enzymes or genetic or immune compounds in tissue;  if so, the more  
specific subheading /enzymology or /immunology should be used on the organ and  
any disease rather than /chem or /metab; /genetics is an AQ for diseases but not  
for organs or other anatomical terms except for some subcellular terms such as  
MITOCHONDRIA, so /chem or /metab should be used on the tissue in which the  
genetic compound is localized.  
 
Immunohistochemical demonstration of C3 levels in the kidney in IgA  
glomerulonephritis using an immunoperoxidase technique. 
COMPLEMENT 3 / * anal 
KIDNEY / * immunol 
GLOMERULONEPHRITIS, IGA / * immunol 
IMMUNOPEROXIDASE TECHNIQUES 
 
Immunoenzyme analysis of DNA in mitochondria of the facial muscles in familial  
Bell's palsy. 
FACIAL MUSCLES / * chem 
MITOCHONDRIA, MUSCLE / *genet 
DNA, MITOCHONDRIAL / * anal 
BELL'S PALSY / * genet 
IMMUNOENZYME TECHNIQUES 
 

25.14		Three subheadings which are frequently used in indexing chemicals,  
and which can be thought of as either analytical or metabolic, are /blood,  
/cerebrospinal fluid, and /urine. The following examples will use /blood as  
representative of the other two subheadings. 
 

25.14.1	Use the subheading /blood for a study of the analysis of a compound  
in the blood or blood cells, or its metabolism in blood or blood cells, even if  
the study is performed in vitro. 
 
Analysis of blood sodium. 
SODIUM / * blood 
 
Transport of sodium in isolated erythrocytes. 
SODIUM / * blood 
ERYTHROCYTES / * metab 
BIOLOGICAL TRANSPORT 
IN VITRO (check tag) 
 

25.14.2	If a pre-coordinated MeSH heading exists for a substance in the  
blood, use it rather than indexing the substance with the subheading /blood. 
 
Analysis of blood proteins. 
BLOOD PROTEINS / * anal 
(Not: PROTEINS / * blood) 
 

25.14.3	Do not use the term BLOOD CHEMICAL ANALYSIS routinely in addition to  
or instead of indexing a specific chemical with the subheading /blood.  BLOOD  
CHEMICAL ANALYSIS should be reserved for general articles, such as articles on  
methods or instrumentation irrespective of any specific compound. 
 
If the methods or instrumentation are particularly discussed in an article on  
the analysis of a specific blood chemical, and if no MeSH term exists for the  
specific technique, BLOOD CHEMICAL ANALYSIS may be added to the article with the  
subheading desired, but it must be made NIM (see section 19.7.4). 
 
A new instrument for analyzing blood ferritin levels. 
FERRITIN / * blood 
BLOOD CHEMICAL ANALYSIS / instrum 
 
But: A newly designed radioimmunoassay instrument for analyzing  blood ferritin  
levels. 
FERRITIN/ * blood 
RADIOIMMUNOASSAY / * instrum 
EQUIPMENT DESIGN  
(Not: BLOOD CHEMICAL ANALYSIS / instrum) 
 

25.14.4	MeSH contains many Category C terms for diseases in which there is a  
deficiency or excess of a specific compound in the blood: examples include  
HYPOCALCEMIA and HYPERCALCEMIA, HYPOKALEMIA and HYPERKALEMIA, HYPOGLYCEMIA and  
HYPERGLYCEMIA. These terms should be reserved for articles on disease states. 
 
Frequently we see articles in which an author uses this type of-emia  
nomenclature but where there is no actual disease; in these cases, index the  
compound with the subheading /blood (or the pre-coordinated BLOOD term) instead  
of the disease term. 
 
The hypokalemic effect of thiazide diuretics.  
(Author is merely studying what the drugs do to levels of potassium in the  
blood) 
DIURETICS, THIAZIDE / * pharmacol 
POTASSIUM / * blood 
DEPRESSION, CHEMICAL 
			 
But: Severe hypokalemia caused by an overdose of the diuretic  
hydrochlorothiazide. 
HYPOKALEMIA / * chem ind 
HYDROCHLOROTHIAZIDE / * pois 
DIURETICS, THIAZIDE / * pois 
OVERDOSE / compl 
 

25.14.5	"Plasma" and "serum" are often used loosely by authors as synonymous  
with "blood"  for articles on blood levels of various substances.  
 
Index any article on "plasma" levels of a compound as just the compound with the  
subheading /blood; do not add PLASMA unless the author makes a distinction  
between levels in plasma versus whole blood, serum, or specific blood cells. 
 
Plasma copper levels in Wilson's disease. 
COPPER / * blood 
WILSON'S DISEASE / * blood 
 
But: Elevated levels of hydrocortisone in the plasma and erythrocytes in  
patients with Addison's disease. 
HYDROCORTISONE / * blood 
ADDISON'S DISEASE / * blood 
PLASMA / * metab 
ERYTHROCYTES / * metab 
 

25.15		Index a drug or chemical administered exogenously to study a  
physiologic process or to diagnose a disease with the subheading /diagnostic  
use. Whether the term with /diagnostic use is IM or NIM depends on the article;  
in many cases it is third-tier and should not even be indexed. 
 
Thyrotropin-releasing hormone stimulation of TSH release in the diagnosis of  
hyperthyroidism. 
THYROTROPIN-RELEASING HORMONE / * diag use 
TSH / * secret 
HYPERTHYROIDISM / * diag 
STIMULATION, CHEMICAL 	 
 
Can bromsulphalein be used to study liver function in pregnancy? 
BROMSULPHALEIN / * diag use 
LIVER FUNCTION TESTS / * methods 
PREGNANCY / * physiol 
 
Liver metabolic function in pregnancy.  
(A page of discussion devoted to the bromsulphalein test)  
LIVER / * metab 
PREGNANCY / * metab 
BROMSULPHALEIN / diag use 
LIVER FUNCTION TESTS / methods 
 
Liver metabolism in pregnancy.  
(Bromsulphalein mentioned in 1 sentence in Materials and Methods) 
LIVER / * metab 
PREGNANCY / * metab 
 

25.15.1	The subheading for radioisotopes used in radionuclide imaging is  
/diagnostic use. Radioisotopes ("tracers") may also be used to label chemical  
compounds so that their pharmacokinetics can be studied by seeing where the  
radioactivity goes. The subheading to use on the radioisotope in a tracer study  
is also /diagnostic use (not /pharmacokinetics, because the /pharmacokinetics of  
the isotope itself are not being studied). As with other compounds used  
diagnostically, tracers are often very routine and are considered to be third- 
tier unless especially discussed. 
 
Thallium radioisotope imaging of the heart. 
THALLIUM RADIOISOTOPES / * diag use 
HEART / * radionuclide 
 
Pharmacokinetics of [76Br]bromospiperone. 
(Has a long section about the fact that bromine radioisotopes are used  
infrequently but were desirable for this study) 
4-bromospiperone / * pharmacokin 
BROMINE RADIOISOTOPES / diag use 
 
Pharmacokinetics of [14C]salbutamol. 
(The radioisotope mentioned briefly in Materials and Methods) 
SALBUTAMOL / * pharmacokin 
 

25.15.2	Indicators and reagents used in performing various laboratory tests  
as well as stains, monoclonal antibodies, etc. used merely to stain tissue ex  
vivo should be indexed with no subheading; save /diagnostic use for chemicals  
which are administered to diagnose a disease or to demonstrate a process  
occurring in the body. 
 
Immunohistochemical demonstration of acetylcholine in nerve fibers using  
monoclonal antibodies. 
ACETYLCHOLINE / * anal 
NERVE FIBERS / * chem 
IMMUNOHISTOCHEMISTRY / methods 
ANTIBODIES, MONOCLONAL 
 
Visualization of nerve degeneration by administration of monoclonal antibodies  
to nerve tissue proteins. 
* NERVE DEGENERATION 
ANTIBODIES, MONOCLONAL / * diag use 
NERVE TISSUE PROTEINS / * immunol 
 
Restriction mapping with the HaeIII endonuclease. 
RESTRICTION MAPPING / * methods 
* HAEIII ENDONUCLEASE 
 

25.16		When indexing biochemistry articles, any article which contains  
genetic sequences must be flagged for the specialists inputting data into the  
GenInfo Backbone Database, using the red SEQUENCE DATA flag; at the same time,  
the term MOLECULAR SEQUENCE DATA must be indexed. See Chapter 28 for a  
discussion of biochemical genetics and the rules for flagging items for the  
GenInfo Backbone Database. 
 

25.17		Gene Symbols often appear in articles on biochemical genetics. See  
Chapter 40 for instructions on indexing Gene Symbols. 
 

25.18		MeSH has many terms to describe molecular characteristics or  
reactions studied in biochemistry; some examples are given below. These  
descriptive terms should be made NIM when a specific chemical or group of  
chemicals is made IM; the terms are IM concepts only for very general articles  
irrespective of any specific compound(s). 
 
BASE COMPOSITION			OXIDATION-REDUCTION					 
		HYDROXYLATION 
PROTEIN DENATURATION		CARBOHYDRATE SEQUENCE 
 
Sequence of myosin and its messenger RNA. 
MYOSIN / * chem / * genet 
RNA, MESSENGER / * chem 
AMINO ACID SEQUENCE 
BASE SEQUENCE 
MOLECULAR SEQUENCE DATA 
 
Inferring amino acid sequence from nucleic acid sequence. 
* AMINO ACID SEQUENCE	 
* BASE SEQUENCE 
 

25.19		Enzymes are studied in almost all fields of biomedicine. MeSH  
contains hundreds of enzymes and even more are available in the Chemical Tool.  
The authority for enzyme headings is the Enzyme Nomenclature published by the  
International Union of Biochemistry and Molecular Biology. 
 
The indexing of enzymes varies according to the context in which they are  
discussed. 
 

25.19.1	The most common concept to be covered when indexing an enzyme is its  
"activity". Enzyme activity is indexed as the /metabolism of the enzyme, paired  
with /enzymology on any organ, organism, or disease in which the activity is  
studied. 
 
Glutamine synthetase activity in Escherichia coli. 
ESCHERICHIA COLI / * enzymol 
GLUTAMINE SYNTHETASE / * metab 
 
Brain hexokinase activity in diabetes mellitus. 
BRAIN / * enzymol 
DIABETES MELLITUS / * enzymol 
HEXOKINASE / * metab 
 

25.19.2	If the activity of the enzyme is demonstrated in a specific body  
fluid, the more specific subheading is used rather than /metabolism. 
 
Activity of cerebrospinal fluid hexosaminidases. 
HEXOSAMINIDASES / * csf 
 

25.19.3	If the enzyme activity is studied in a blood cell, use /blood on the  
enzyme and /enzymology on the blood cell. 
 
Esterase activity in erythrocytes. 
ESTERASES / * blood 
ERYTHROCYTES / * enzymol 
 

25.19.4	Although enzyme activity in a disease is usually indexed as the  
/enzymology of the disease, enzyme levels may be a means of diagnosis and should  
then be indexed with the term ENZYME TESTS, coordinated with /diagnosis rather  
than /enzymology on the disease. 
 
Diagnosis of lead poisoning by demonstrating elevated levels of delta- 
aminolevulinic acid dehydratase in the blood. 
LEAD POISONING / * diag 
AMINOLEVULINIC ACID DEHYDRATASE / * blood 
* ENZYME TESTS 
 
But: Erythrocyte porphobilinogen deaminase in lead poisoning.  
(Levels are studied but not discussed as a diagnostic test) 
ERYTHROCYTES/ * enzymol 
PORPHOBILINOGEN DEAMINASE / * blood 
LEAD POISONING / * enzymol 
 

25.20		There are many elements in MeSH in three forms: the element, the  
isotope of the element, and the radioisotope of the element. When a pre- 
coordinated term does not exist for the isotope or radioisotope form, index the  
element (IM) and coordinate with ISOTOPES (NIM) or RADIOISOTOPES (IM),  
respectively. The annotations indicate when to index the element, its isotope  
form or its radioisotope form. 
 

25.20.1	ISOTOPES as an IM concept is reserved for general articles only.  
Whether used as an IM concept or NIM as a coordinate for a specific element, the  
term has no AQs. Similarly, a pre-coordinated (ELEMENT) ISOTOPES term is indexed  
with no qualifiers. 
 

25.20.2	The term RADIOISOTOPES may be indexed IM for general articles on  
radioisotopes, but it may also be used IM as a coordinate for the radioisotope  
form of an element for which no pre-coordinated term exists; in these cases, use  
the same subheading on both the element term and RADIOISOTOPES. 
 

25.20.3	If an element is naturally radioactive, a pre-coordinated  
RADIOISOTOPES term does not exist for it, nor should the term RADIOISOTOPES be  
added as a coordinate. Each of the naturally radioactive elements is treed under  
ELEMENTS, RADIOACTIVE in Category D1 and has been annotated "naturally  
radioactive". 
 

25.20.4	An element is sometimes written with an "m" after the atomic weight  
(barium 137m, technetium-99m, 204mPb, etc.). The "m" stands for "metastable" and  
refers to an unstable state which can change to a more or less stable state. 
 
To index an element or isotope followed by the letter "m", use the appropriate  
radioisotope heading for the element (barium 137m = BARIUM RADIOISOTOPES even  
though barium 137 = BARIUM + ISOTOPES). In the case of an element which is  
naturally radioactive, merely index the term for the element itself  
(technetium99m = TECHNETIUM). 
  

25.20.5	See section 25.15.1 for the use of /diagnostic use on radioisotopes  
used in imaging or as tracers. 
 

25.20.6	The effect of a radioisotope or radioactive element is related to  
its radioactivity, not its chemical identity. Do not index the effects of a  
radioisotope or radioactive element with the subheading /pharmacology; index the  
isotope or element with no subheading, and use /radiation effects on the target  
of its effects.  
 
The effect of radiocobalt on liver metabolism. 
LIVER / * rad eff / metab 
* COBALT RADIOISOTOPES  
 

25.20.7	Similarly, the subheading on a disease treated with a radioactive  
element or radioisotope is /radiotherapy, not /drug therapy. 
 
Radioiodine therapy of thyroid neoplasms. 
IODINE RADIOISOTOPES / * ther use 
THYROID NEOPLASMS / * radiother 
 

25.20.8	Chemicals may be indexed with the subheading /radiation effects for  
articles about the effects of radiation on them; the subheading is not used with  
a radioisotope or radioactive element for its effects. 
 
Effects of uranium on blood proteins. 
* URANIUM 
BLOOD PROTEINS / * rad eff 
 

25.21		Index anesthetics without subheadings for articles merely on their  
use as anesthetics; in most cases, an anesthesia term from Category E will also  
be required. 
 
Ketamine as an intravenous anesthetic for surgery in horses. 
* KETAMINE 
* ANESTHETICS, DISSOCIATIVE 
ANESTHESIA, INTRAVENOUS / * vet 
HORSES / * surg 
ANIMAL (check tag) 
 

25.21.1	Most articles on anesthetics, however, discuss some aspect of the  
particular anesthetic being studied: its administration, adverse effects,  
pharmacokinetics, etc. In these cases it is perfectly acceptable to use the  
appropriate subheading with the anesthetic. 
 
Adverse effects of halothane inhalation anesthesia in relation to the amount  
administered. 
HALOTHANE / * adv eff / admin 
ANESTHETICS, INHALATION / * adv eff / admin 
ANESTHESIA, INHALATION / * adv eff 
DOSE-RESPONSE RELATIONSHIP, DRUG 
 
Effects of inhaled isoflurane on liver enzymes. 
ISOFLURANE / * pharmacol 
ANESTHETICS, INHALATION / * pharmacol 
LIVER / * drug eff / enzymol 
 

25.22		When indexing a chemical compound from an animal 
(mouse monoclonal antibodies, rat prolactin, etc.), always check the tag ANIMAL.   
In addition, check the tag or index the MeSH heading for the animal species if  
the animal is the point of the article, or if the species appears in the title  
or statement of purpose for the article.  It is not necessary to pick up the  
animal species if it is just mentioned in passing in the text of the article.