home » resources »


This is a comprehensive list of abbreviations that appear in APS journals. Note that some terms are shown as highlighted APS Toolkit codes (e.g., «obar»), because the symbols they represent cannot be displayed in a web browser.

If you find any errors in this list or think of a term that should be on it, contact the Web Copy Editor.


A absolute temperature, or absorbance, or amplitude
A area
[A] dissociated proteinate concn.
AAALAC American Association for Accreditation of Laboratory Animal Care
(A-a)Do2 alveolar-arterial O2 difference
(A-a)«po2» alveolar-arterial «po2» difference
A/B apex-to-base ratio
Ab antibody
ABA aortic baroreceptor activity
ABC avidin-biotin complex (for staining)
ABD aerosol bolus dispersion
abd abdominal
ABFV aortic blood flow velocity
ABG arterial blood pH and gas tensions
ABP arterial blood pressure, or (infrequently) ambulatory blood pressure
Ac capillary surface area
AC alternating current
ACA anterior cerebral artery supply
ACC acetyl-CoA carboxylase
ACDH 3-hydroxyacyl-CoA dehydrogenase
ACE angiotensin I-converting enzyme
ACEI angiotensin-converting enzyme inhibitor
ACF autocorrelation function
ACh acetylcholine
AChE acetylcholinesterase
aCSF artificial cerebrospinal fluid
ACTH adrenocorticotropic hormone
A/D analog-to-digital (converter)
ADA adenosine deaminase
ADAM aerosol-derived airway morphometry or 9-anthryldiazomethane
ADC analog-to-digital converter
ADPase adenosinediphosphatase
ADPKD autosomal dominant polycystic kidney disease
ADS anatomic dead space
ADX adrenalectomized
AFC alveolar fluid clearance
aFGF acidic fibroblast growth factor
Ag-AgCl silver-silver chloride; most often used with respect to an electrode (do not define)
AHVR acute hypoxic ventilatory response
AIC Akaike information criterion
AICAR 5-aminoimidazole-4-carboxamide-1-β-d-ribofuranoside
AIDS acquired immunodeficiency syndrome
AIM ambulatory impedance monitor
AIR automated image registration
Alb albumin
ALD anterior latissimus dorsi (muscle)
ALI acute lung injury
ALS acid labile subunit
ALT alanine aminotransferase
AM acetoxymethyl ester (e.g. fura-2 AM); ante meridian (do not define)
7-AMC 7-amino-4-methyl-coumarin
AMP adenosine 5´-monophosphate (do not define)
AMPA dl-α-amino-3-hydroxy-5-methylisox     azole-propionic acid
AMPase adenosinemonophosphatase (do not define)
AMP-CP α,β-methyleneadenosine 5´-diphosphate
AMPK AMP-activated protein kinase
AMS acute mountain sickness
AMS-C acute mountain sickness-cerebral
amu atomic mass units
AMV avian myeloblastosis virus
ANCOVA analysis of covariance
ANF atrial natriuretic factor
ANG I angiotensin I
ANOVA analysis of variance
ANP atrial natriuretic peptide
ANR Aspergillus nitrate reductase
ANTU α-naphthylthiourea
Ap aprotinin
A-P anterior-posterior (change to AP - anteroposterior)
4-AP 4-aminopyridine
AP-5 dl-2-amino-5-phosphonovaleric acid
AP atriopeptin, or anteroposterior (stereotaxic coordinate - do not define), or antigen presentation, or area postrema
AP-1 activator protein-1
APA action potential amplitude
APAAP alkaline phosphatase anti-alkaline phosphatase
APAF-1 apoptotic protease-activating factor 1
APC antigen presenting cell
APD90 action potential duration at 90% duration
APE atom percent excess
ApEn approximate entropy
apoA apo(a) [different], apoB, apoAI, apoB-100, apoB-48, etc. apolipoproteins
apo A-IV apolipoprotein A-IV
APTT activated partial thromboplastin time
AQP-1 aquaporin-1 (some authors say AQP1; retain author's style)
AQP-3 aquaporin-3
AQP-5 aquaporin-5
ARDS acute respiratory distress syndrome (always use "acute" instead of "adult")
ASA acetylsalicylic acid
ASD atrial septal defect
ASM airway smooth muscle
ASR acoustic startle reflex
AST aspartate aminotransferase
AT anaerobic threshold
ATBF adipose tissue blood flow
atm atmospheres (do not define) (pressure)
[A]tot total concn of weak acids
ATPase adenosinetriphosphatase (do not define)
ATw amplitude of T wave
au or AU arbitrary units
AUC abbreviation for 3 amino acids (do not define), or area under the curve (define)
a-v arteriovenous
AV atrioventricular
AVA arteriovenous anastomoses
(a-v)HbO2 arteriovenous difference in Hb-bound O2
AVN atrioventricular node
(a-v)O2 arteriovenous O2 difference
AVP arginine vasopressin
AVSM airway vascular smooth muscle
AZ acetazolamide


b0,+sodium-independent transporter
B0,+sodium-dependent equivalent
B0eicosanoic competitor
BAECbovine aortic endothelial cells
BALbronchoalveolar lavage
BALFbronchoalveolar lavage fluid
β-APPβ-amyloid precursor protein
BAPTA1,2-bis(2-aminophenoxy)ethane-N,N,N´,N´-tetraacetic acid
BATbrown adipose tissue
BBBblood-brain barrier
BCAbicinchoninic acid
BCAAbranched chain amino acid
BCAATbranched chain amino acid transaminase
BCIP5-bromo-4-chloro-3-indolyl phosphate
BCMbody cell mass
BCOADHbranched chain 2-oxo acid dehydrogenase
BDbase deficit
BDNFbrain derived neurotrophic factor
BDM2,3-butanedione monoximine
BFblood flow
bFGFbasic fibroblast growth factor
BFtottotal blood flow
BFDLWblood-free dry lung weight
β-HBAβ-hydroxybutyric acid
BHRbronchohyperresponsive, or bronchial hyperreactivity
BIAbioimpedance analyzer
BISbioimpedance spectroscopy
BLESbovine lipid extract surfactant
Bmax maximum binding capacity or density of binding sites
BMCbone mineral content
BMDbone mineral density
BMEbasal medium Eagle
BMKbig mitogen-activated protein kinase
BMPbone morphogenetic protein II
BMSbulk magnetic susceptibility
bNOSbrain cell nitric oxide synthase (NOS)
BNPbrain natriuretic peptide
BMRbasal metabolic rate
bpbase pair
BPbinding protein
BPAECbovine pulmonary endothelial cells
8-BrcAMP8-bromoadenosine 3´,5´-cyclic monophosphate
8-BrcGMP8-bromoguanosine 3´,5´-cyclic monophosphate
BRSbaroreceptor reflex sensitivity
BSAbovine serum albumin (do not define)
BSTBA4-benzoyl-5-sulfamoyl-3(3-thenyloxy)benzoic acid
BTbretylium tosylate
BTEEN-benzoyl-l-tyrosine-ethyl ester
BTPSbody temperature pressure saturated (do not define)
BUNblood urea nitrogen
t-buOOHt-butyl hydroperoxide
BVblood volume
BVBbilateral vagal block
BWbody weight (also "BWt")


Ccircumference, or capacitance, or conductance
Ccompliance, or concentration
CAcarbonic anhydrase
Ca50calcium concn. producing half-maximal activation
Cababdominal components
cADPrcyclic ADP ribose
[Ca2+]iintracellular calcium concentration
cAMPadenosine 3´,5´-cyclic monophosphate
CAOcoronary artery occlusion
Ca{↓O2}arterial O2 content
CAPcarotid arterial pressure
CBcarotid body
CBCcomplete blood cell counts
CBFcerebral blood flow, or coronary blood flow
CBGcortisol-binding globulin
CBVcerebral blood volume
CCCPcarbonyl cyanide m-chlorophenylhydrazone
CCDcharge-coupled device
CCFcross-correlation function
CCK-A alimentary CCK
CCK-B brain CCK
CCK-8cholecystokinin octapeptide
Cco22CO2 concentration
CCSPclear cell secretory protein
CDcluster of differentiation, or cortical density
CDΩ-18glycoprotein complex
CDHcongenital diaphragmatic hernia
CDPcontinuous distending pressure, or carotid distending pressure
Cdyndynamic compliance
CEcatecholestrogen, or cholesteryl ester
C. elegans Caenorhabditis elegans
CETPcholesterol ester transfer protein
CETPacholesterol ester tranfer protein activity
CFcenter frequency, or cystic fibrosis
C/Fcapillary-to-fiber ratio
CFBScolostrums-free bovine serum
CFCcapillary filtration coefficient
CFSEcarboxyfluorescein diacetate succinimidyl ester
CFTRcystic fibrosis transmembrane conductance regulator
CFUcolony-forming unit
CGDchronic granulomatous disease, or cumulative Gaussian distribution
cGMPguanosine 3',5'-cyclic monophosphate
CGRPcalcitonin gene-related peptide
CgTxω-conotoxin GVIA (Cg is for Conus geographus)
CH50total hemolytic complement
CHDcoronary heart disease
CHFcongestive heart failure
CHO carbohydrate, or Chinese hamster ovary
ChoREcarbohydrate response elements
ChTX or CTXcharybdotoxin
CIcardiac index (l/min/m2--change to use chem point), or confidence interval
CICcontractile interstitial cells
CKcreatine kinase
CLcycle length, or cardiolipin
Cllung compliance
CLPcecal ligation and perforation
CLScalf lung surfactant
CMcenter of mass
CMAPcompound muscle action potential
CMNcaudal mediastinal lymph node
CMRO2cerebral metabolic rate of oxygen
CMScervical magnetic stimulation
CMVcytomegalovirus, or conventional mechanical ventilation, or volume-controlled mechanical ventilation
CNAPcontinuous negative airway pressure
CNEPcontinuous negative extrathoracic pressure
CNS central nervous system, or complete natural surfactant
CNTFciliary neurotrophic factor
CNTFR-α CNTF receptor-α 
COcardiac output (l/min), or carbon monoxide
C{↓O2}O2 content
CO2carbon dioxide
COIcyclooxygenase inhibition
COLBPcyclooxygenase L-form transcript binding protein
ConAconcanavalin A
COPcolloid osmotic pressure
COPDchronic obstructive pulmonary disease
COPiinterstitial colloid osmotic pressure
COPpplasma colloid osmotic pressure
COSYcorrelation spectroscopy
COUP-TFchicken ovalbumin upstream promotor-transcription factor
C-OVAchicken ovalbumin
COX cyclooxygenase, or cytochrome-c oxidase
Cpperfusate concentration of 125I-albumin
CPcreatine phosphate, or center of pressure
CPAPcontinuous positive airway pressure
CPBcardiopulmonary bypass
CPEPcontinuous positive extrathoracic pressure
CPKcreatine phosphokinase
cPLA2cystolic, calcium-dependent phospholipase A2
cpmcounts per minute (always lowercase)
CPNcaudate putamen nucleus
CPNIcarboxypeptidase N inhibitor
CPP(2-carboxypiperazin-4-yl)-propyl-1-phosphanoic acid, or cerebral perfusion pressure
cpscycles per second
CPT Icarnitine palmitoyltransferase I
CPT-cAMP8-(4-chlorophenylthio)adenosine 3´,5´-cyclic monophosphate
Crchromium (don't define), or creatine
CR1complement receptor 1
Crcrib cage components
cRccentral chemoreceptor
CRCconcentration-response curve
CREcAMP response element
CRFcorticotropin-releasing factor
CrPcreatine phosphate
CrPicchromium picolinate
Crsrespiratory system compliance
CrTcrista terminalis
CScoronary sinus, or citrate synthase, or corticosteroids
CSAcross-sectional area
CSFcerebrospinal fluid
CSNcarotid sinus nerve
CSPcarotid sinus pressure
CTconduction time or contraction time or computerized tomography or critical threshold
CTPcytidine 5´-triphosphate (do not define)
CTPRcalculated total peripheral resistance
CURECenter for Ulcer Research and Education
CVcoefficient of variation, or conduction velocity
CVCcutaneous vascular conductance
%CVCmaxpercentage of maximum CVC
CVDcardiovascular disease
CVFcobra venom factor
CVLMcaudal ventrolateral medulla
cVMScaudal ventrolateral medullary surface
C«obar»v{↓O2}mixed venous O2 content
Cv{↓O2}venous O2 content
CVPcentral venous pressure, or cerebrovascular resistance
CVQcoefficient of variation of relative blood flow
CytAcytosine arabinoside


Δ change in...
Δ«obar»Vbolus mean volume shift
doptical pathlength
Ddiameter, or diffusion coefficient, or fractal dimension
apparent diffusion coefficient
Ddeposited fraction of gas, or density
[D]drug concentration
D50W, D5W50% dextrose in water, or 5% dextrose in water
Dadaltons (kDa = kilodaltons)
DACdigital-to-analog converter
DAF-2 DA4,5-diaminofluorescein diacetate
DAPdiastolic arterial pressure
d-AP-7d-(–)-2-amino-7-phosphoheptanoic acid
DBcAMPdibutyryl adenosine 3´,5´-cyclic monophosphate
DBcGMPdibutyryl guanosine 3´,5´-cyclic monophosphate
DCdirect current
DCCDN, N´-dicyclohexylcarbodiimide
DCDIdiffusion-convection-dependent ventilation inhomogeneity
DCF-DA2´,7´-dichlorodihydrofluorescein diacetate
DCSdecompression sickness
[α-32P]dCTP32P-labeled deoxycytidine triphosphate (do not define)
DDAVP1-desamino-8-d-arginine vasopressin or desmopressin
DEAEdiethylaminoethyl (do not define )
DEHSdi-(2)-ethylhexyl sebacate
dEMGdifferentiated EMG
deoxy-Hbdeoxygenated Hb
DEPCdiethyl pyrocarbonate
dfdegrees of freedom
DFdeposition fraction
DHKEdihydroketoprostaglandin E
DHLAdihydrolipoic acid
DHPRdihydropyridine receptor
diamdiameter (spell out in text)
DIDS4,4´-diisothiocyanostilbene-2,2´-disulfonic acid
DKEdynamic knee extension
DlCOCOlung CO-diffusing capacity
DLHdl-homocysteic acid
DlNONOlung NO-diffusing capacity
DLWdry lung weight, or doubly labeled water
dmdry mass
Dmmembrane diffusing capacity
DmCOCO-diffusing capacity of alveolar-capillary membrane
DMDDuchenne muscular dystrophy
DMEMDulbecco's modified Eagle's medium
DMPP1,1-dimethyl-4-phenylpiperazinium iodide
DMRTDuncan's multiple-range test
DMSOdimethyl sulfoxide
DNasedeoxyribonuclease (do not define )
DNPH2,4-dinitrophenyl hydrazine
dNTP2-deoxynucleotide 5´-triphosphate
«odot»Do22oxygen delivery, or oxygen diffusion
DOCAdeoxycorticosterone acetate
DOMSdelayed-onset muscle soreness
DPACdiphenylamine-2-carboxylic acid (but preferred version is N-phenylanthranilic acid)
dP/dtchange in pressure over time
dpmdisintegrations per minute
DPPC1,2-dipalmitoyl-sn-3-glycero phosphoryl choline
DRDahl resistant
DRGdorsal root ganglion, or dorsal respiratory group
dsdouble-strand (e.g., DNA)
DSDahl sensitive
DSPdithiobis (succinimidyl propionate)
DTABdodecyltrimethylammonium bromide
DTHdelayed-type hypersensitivity
DTNB5,5´-dithiobis(2-nitrobenzoic acid)
DTPAdiethylenetriamine pentaacetic acid
DUdensity units
DVductus venosus
dwdry weight
D/Wdry-to-wet weight ratio
DXAdual-energy X-ray absorptiometry (if au has DEXA, leave it)
dZ/dtfirst derivative of pulsatile impedance (Z)
dZ/dtmaxmaximum of impedance (Z) derivative


ηhysteresivity, or viscosity
Eelastance, or mechanical efficiency, or shear strain, or enrichment
Eelastic modulus
Eaenergy of activation
EAAexcitatory amino acid
EADeffective air space (airway) dimension
EARearly airway response
EBAalbumin labeled with Evans Blue
EBDEvans blue dye
EC5050% effective concentration (do not define)
Eccellular electromotive force
Ecoxygen diffusion conductance
ECDethyl cysteinate dimer
ECFextracellular fluid
ECLenhanced chemiluminescence
ECMextracellular matrix
ECMOextracorporeal membrane oxygenation
ECPeosinophil cationic protein
ECWextracellular water
ed.edition (in APS reference style)
Ed. editors (in APS reference stylefor book chapters)
ED50half-maximal effective dose
EDCFendothelium-derived contracting factor
EDHFendothelium-derived hyperpolarizing factor
EDLextensor digitorum longus
EDNeosinophil-derived neurotoxin
EDRFendothelium-derived relaxing factor (i.e., nitric oxide)
Edyndynamic elastance
Edynidynamic elastance during inspiration
Edynedynamic elastance during expiration
EELVend-expiratory lung volume
EEPend-expiratory pause
EERestimated energy requirement
EFPECepididymal fat pad endothelial cells
EFSelectrical field stimulation
EGFepidermal growth factor
EGTAethylene glycol-bis(β-aminoethyl ether)-N, N, N´,N´-tetraacetic acid (do not define)
EHSEngelbreth-Holm-Swarm (matrix)
EIevenness index
EIAenzyme immunoassay
EILVend-inspiratory lung volume
EIPend-inspiratory pause
EIPAethylisopropyl amiloride
EIPHexercise-induced pulmonary hemorrhage
Ellung elastance
ELISAenzyme-linked immunosorbent assay
ELRexcitatory lung reflex
EMCLextramyocellular lipid
«odot»Emetabmetabolic rate
EMGdiadiaphragmatic electromyogram
EMGdiaplsdiaphragmatic electromyogram in the pulse breaths
EMGggelectromyographic activity of the genioglossus
EMGnknuchal electromyogram
EMSAelectrophoretic mobility shift assay
EMGsmsternomastoid muscle electromyogram
ENethmoidal nerve
ENAepithelial cell-derived neutrophil-activating protein (example: ENA-78)
ENaCepithelial Na channels; rENaC, rat ENaC, also α-, β-, and γ-ENaC
ENOelimination rate of NO
eNOSendothelial NOS
EPAextrapulmonary artery
EPOeosinophil peroxidase
EPRelectron paramagnetic resonance
EPSPexcitatory postsynaptic potential
ERestrogen receptor
ERKextracellular regulated kinase (also ERK1, ERK2)
ER{↓O2}oxygen extraction ratio
ER{↓O2|crit}critical oxygen extraction ratio
ERTestrogen-replacement therapy
ERVexpiratory reserve volume
ESelectrical stimulation
ESPVRend-systolic pressure-volume relationship
Est, lstatic pulmonary elastance of the lung
ETendotracheal, or endothelin
ETCelectron transport chain
EUendotoxin units (be sure to define)
EVLWextravascular lung water


frespiratory frequency (always roman)
ffrequency, or flux (electrical)
Fflow (Roman), or force, or fluorescence, or infusion rate
«obar»Fground force
FFaraday constant, or frequency
4-FFoley catheter, size 4
F360fluorescence at 360-nm excitation
FA fatty acids, or filtered air
FAB/MSfast-atom bombardment mass spectrometry
FAKfocal adhesion kinase
FASfatty acid synthase
5F-BAPTA5-fluoro-1,2-bis(2-aminophenoxy)ethane-N,N,N´,N´-tetraacetic acid
FBFforearm blood flow
FBSfetal bovine serum
«obar»Fbwforce to support body weight
FCfree cholesterol
fccharacteristic frequency
FCCPcarbonyl cyanide p-trifluormethoxyphenylhydrazone
FCIfood conversion index
Fefraction of tissue water that is extracellular
FEFforced expiratory flow
FEF75forced expiratory flow after exhalation of 75% FVC
Fe{↓N2O}expiratory fraction of N2O leaving nose
FESfunctional electric stimulation
FETfield effect transistor
Fet{↓CO2}fraction of end-tidal CO2
Fet{↓O2}fraction of end-tidal O2
FEV1forced expiratory volume in 1 s
FEV25-75%forced maximal midexpiratory flow
FFAfree fatty acids
FFMfat-free mass
FFTfast Fourier transform
FFWfat-free weight
FGFfibroblast growth factor
«fico2»inspired CO2 fraction
Fi{↓N2O}inspiratory fraction of N2O
«fio2»inspired O2 fraction
FISSSFondo de Investigaciones Sanitarias de la Seguridad Social
FITCfluorescein isothiocyanate (-labeled dextran)
FLAP5-lipoxygenase activating protein
Fmusmuscle force
FMfat mass, or frequency modulation
Fmaxmaximum calcium-activated force, or maximum force production
FMSfunctional magnetic stimulation
FOforced oscillation
FOVfield of view
FPhfollicular phase
FPLCfast-performance liquid chromatography
4-FrFrench catheter, size 4 (do not define)
FRAFos-related antigen
FRAPferric reducing ability/power
FRCfunctional residual capacity
Froi{↓O2}fraction of O2 in region of interest
FSEfast spin echo
FSHfollicle-stimulating hormone
FSRfractional synthesis rate
FVCforced vital capacity, or forearm vascular conductance
F-VEPflash visual-evoked potential
FVMfluorescent videomicroscopy
FWHMfull-width half-maximum
Fxlateral force
Fyhorizontal force
Fzvertical force


Ggravity, or pulmonary tissue conductance, or applied force, or tissue damping
Gelectrical conductance or resistance
G*complex modulus
storage modulus
G«dprime»loss modulus
1 Ggravity on the ground
G-(1«sbond»17)hecadecapeptide gastrin
GABAγ-aminobutyric acid, also GABAA, GABAB (do not define)
Gaoaortic conductance
GAP-43growth associated protein-43
GAPDHglyceraldehyde-3-phosphate dehydrogenase
GASγ-activation sequence (use the Greek letter)
ΔGATPfree energy of ATP hydrolysis
GBganglionic blocker
gCBFglobal cerebral blood flow
GCgas chromatography
GC/C/IRMSgas chromatography/combustion/isotope ratio mass spectrometry
GC-MSgas chromatography-mass spectrometry
GCRCGeneral Clinical Research Center
GDPguanosine diphosphate (do not define)
GDPβSguanosine 5´-[β-thio]diphosphate, or guanosine 5´-O-(2-thiodiphosphate)
GERgastroesophageal reflux
GERDgastroesophageal reflux disease
GFAPglial fibrillary acidic protein
GFRglomerular filtration rate
GHgrowth hormone
Ghahepatic artery conductance
Giinhibitory G protein (do not define)
GIPgastric inhibitory peptide
GITC2,3,4,6-tetra-O-acetyl-β-d-glucopyranosyl isothiocyanate
Gjjunctional conductance
Glpulmonary conductance
GLIPglycerol intrinsic protein
GLMgeneral linear model
GLPglucagon-like peptide
Gluglutamate, or glucose
GLUT1, GLUT2, etc.glucose transporter isoform (do not define)
gmmitochondrial conductance
Gmaxmaximum conductance change (electrical)
GMBFgastric mucosal blood flow
GMPguanosine 5´-monophosphate
GMSAgel mobility shift assays
Gnhistone-induced conductance (electrical)
GnRHgonadotropin-releasing hormone
GoFgoodness of fit
G-6-PDHglucose-6-phosphate dehydrogenase
GPDHα-glycerophosphate dehydrogenase
GPOgov't printing office
Gpp(NH)p5´-guanylyl imidodiphosphate
GPXglutathione peroxidase
GRDglutathione disulfide reductase
GRFgrowth hormone releasing factor, or ground reaction force
GRPgastrin-releasing peptide [GRP-(1«sbond»27)]
GSDgeometric standard deviation
GSHglutathione or reduced glutathione
GSRgalvanic skin response
GSSGglutathione disulfide or oxidized glutathione
GSTglutathione S-transferase
Gttransepithelial conductance
Gtitissue damping
GTPγSguanosine 5´-O-(3-thiotriphosphate)
Gzvertical acceleration (i.e., head-to-toe acceleration)


h inactivation in presence of drug
H height, or elastance
H-7 1-(5-isoquinolinesulfonyl)-2-methylpiperazine
H-8 N-(2-[methylamino]ethyl)-5-isoquinolinesulfonamide
HA hyaluronic acid, or hydrophobic apoprotein, or high altitude
HABFV hepatic arterial blood flow velocity
HACE high-altitude cerebral edema
HADH 3-hydroxyacyl-CoA-dehydrogenase
HAF hepatic arterial blood flow
HAP hepatic arterial pressure
HAR hepatic arterial vascular resistance
Hb hemoglobin
H-B Hering-Breuer
HbCO carboxyhemoglobin
HbO2 oxyhemoglobin
HBO2 hyperbaric oxygen
HBSS Hanks' balanced salt solution
HC hypercholesterolemia
hCGRP human calcitonin gene-related peptide
δ-HCH δ-hexachlorocyclohexane
Hct hematocrit
HCVR hypercapnic ventilatory responses
HDL high-density lipoprotein
HDNF head-down neck flexion
HDTA hexamethylenediamine-N,N,N´,N´-tetraacetate
H & E hematoxylin and eosin--common stain for cells (always write out)
HE Haldane effect
HEP high-energy phosphates
HEPES N-2-hydroxyethylpiperazine-N´-2-ethanesulfonic acid
HES hydroxyethyl starch
HETE hydroxyeicosatetraenoic acid
12-HETE 12-hydroxyeicosatetraenoic acid
HFBA n-heptafluorobutyric acid
HFBP high-affinity folate-binding protein
HFOV high-frequency oscillatory ventilation
HG hypoglossal
HGP hepatic glucose production
HGPRT hypoxanthine/guanine 5-phosphoribosyl 1-pyrophosphate
H-H interval hiccup-hiccup interval
HHL hippuryl-histidyl-leucine
HIC higher intensity cycling
HIL hydrostatic indifference level
HIP hydrostatic indifference point
HIV human immunodeficiency virus
HK hexokinase
HLA human leukocyte antigen
Hmax maximal H reflex
HMF hydroxymethylfurfural
4-HNE 4-hydroxynonenal
HNF-3α hepatocyte nuclear factor-3α (also -3β)
HP holding potential, or hydroxylysylpyridinoline
HPETE hydroperoxyeicosatetraenoic acid
hpGRF human pancreatic growth hormone releasing factor
HPLC high-performance liquid chromatography
HPLC-EC HPLC-electrochemical detection
HPNS high pressure neurological syndrome
HPV hypoxic pulmonary vasoconstriction
HRmax maximum heart rate
HRP horseradish peroxidase
HRR heart rate reserve
HRV heart rate variability
HSD honestly significant difference
HSP70 heat shock protein 70 (some authors may use HSP-70)
HSV-1 herpes simplex virus type 1
5-HT 5-hydroxytryptamine (serotonin - preferred usage)
HTGLa hepatic triglyceride lipase activity
Hti tissue elastance
HTR heart transplant recipients
HU hindlimb unweighted, or Hounsfield unit
HUVEC human umbilical vein endothelial cells
HVR hypoxic ventilatory response
HYP hydroxyproline


I current, or leak constant
I inertance, or intensity
I inspiratory (modifier on line)
IAAT intra-abdominal adipose tissue
IACUC Institutional Animal Care and Use Committee
Iaw airway inertance
IBF iliac blood flow
IBI interbreath intervals
IBMX 3-isobutyl-1-methylxanthine
IC inspiratory capacity
IC50 half-maximal inhibitory concentration (do not define)
ICa calcium current
ICa,L L-type calcium channel current
ICAM-1 intercellular adhesion molecule-1
ICD intercapillary distances
icv intracerebroventricular [also iv (intravenous), im (intramuscular), sc (subcutaneous), po (per os)]
ICW intracellular water
ID internal diameter (in parens.) (do not define)
IDF intrathoracic deposition fraction
IDH isocitrate dehydrogenase
Ie current electrodes
IEC intestinal epithelial cell line
iEMG integrated EMG
IF intrinsic factor
IFL inspiratory flow limitation
IFN-γ interferon-γ
IFNEX IFN-γ-enhanced factor X
IGE intravascular gas embolism
IGF-I, II insulin-like growth factor I, II
IGFBP-3 insulin-like growth factor-binding protein-3, -2
IgG immunoglobulin G (do not define)
IK potassium current
IL-1β interleukin-1β
IMCL intramyocellular lipid
IMF intermyofibrillar
IML intermediolateral cell column
IMP inosine 5´-monophosphate
iNOS inducible nitric oxide synthase [also ecNOS (endothelial constitutive NOS), nNOS (neuronal NOS)]
InsP1 inositol 1-phosphate (also IP1)
Ins(1,4)P2 inositol 1,4-bisphosphate (also IP2)
Ins(1,4,5)P3 inositol 1,4,5-trisphosphate (also IP3)
IOD integrated optical denisty
ION infraorbital nerve
IPA intrapulmonary artery
IPG impedance pneumograph
IPPV positive pressure during inspiration
IPS inspiratory pressure support
IPSV inspiratory pressure support ventilation
IPTG isopropylthiogalactoside
IPV in-phase vibration
I/R ischemia-reperfusion
irAP immunoreactive atriopeptin
IRL inspiratory resistance loading
IRMS isotope ratio mass spectrometry
IRS insulin responsive sequence
IRS-1 insulin receptor substrate-1
Isc short-circuit current
ISF interstitial fluid
ISFET ion-sensitive field-effect transistor
ISGF3 IFN-stimulated gene factor 3
ISI interspike interval, or isometric-shortening-isometric
Iso isometric
ISP intrasinus pressure
ITM interpolated twitch moment
ITP intrathoracic pressure
iv intravenous
I-V current-voltage relationship
IVC inferior vena cava
IVIC Instituto Venezolano de Investigaciones Científicas
IVR iliac vascular resistance
IVRT isovolumic relaxation time


JAK janus kinase
JNK c-Jun NH2-terminal kinase


k proportionality factor y = mx + b slope, or rate of binding
K kelvin (degree sign not needed, but use it if there is a chance of confusion with K for potassium, for example)
K' apparent equilibrium constant
KATP channel ATP-sensitive K+ channel
Ka activation constant or affinity constant (do not alter author's definition)
kb kilobase (do not define)
kB kbytes (do not define)
KCa channel Ca2+-activated K+ channel
KCN potassium cyanide (do not define)
KCO CO alveolar volume
Kd dissociation constant
Kf ultafiltration coefficient
Kfc capillary filtration coefficient
KFN Kölliker-Fuse nuclei
kg fractional growth rate
kh rate constant of conductance change
KHB Krebs-Henseleit bicarbonate buffer
KLH keyhole limpet hemocyanin
Ki inhibitor constant
KIC α-ketoisocaproate
KIR channel inward rectifier K+ channel
Km Michaelis-Menten constant (don't define)
K{↓m,|Ca2+} Michaelis-Menten constant for Ca2+
KN-62 1-[N,O-bis(5-isoquinolinesulfonyl)-N-methyl-l-tyrosyl]-4-phenylpiperazine
KPI kunitz protease inhibitor
KRP Krebs-Ringer phosphate
KV channel voltage-dependent K+ channel


l length
L length
LA α-lipoic acid
LAA left atrial appendage
Lac lactate (also La)
LAD left atrial diameter, or left anterior descending coronary artery
LAR late airway response
LAV liquid-assisted ventilation
LB lamellar bodies
LBF leg blood flow
LBNP lower body negative pressure
LC locus coeruleus
LCA leukocyte common antigen
LCATa lecithin-cholesterol acyltransferase activity
LDF laser-Doppler flowmetry
LDH lactate dehydrogenase
LFA lymphocyte functions-associated antigens
LFF low-frequency fatigue
LFR long-latency fractionation response
LG lateral gastrocnemius
LGN lateral geniculate nuclei
LH luteinizing hormone, or lateral hypothalamus
LL log likelihood
LMMP longitudinal muscle-myenteric plexus
LMW low molecular weight
l-NAME «lgname»; NG-nitro-l-arginine methyl ester, or «lwname» Nω
l-NMMA «lgnmma»; NG-monomethyl-l-arginine, or «lwnmma» Nω
l-NNA «lgnna»; NG-nitro-l-arginine, or «lwnna» Nω
Lo optimal (muscle) length
Lp hydraulic conductivity
LPA lysophosphatidic acid
LPC late positive complex
LPh luteal phase
LPK L-type pyruvate kinase
LPL lipoprotein lipase
LPLa lipoprotein lipase activity
LPS lipopolysaccharide
LR likelihood ratio
L-RIE low-resistance inspiratory effort
LRN lateral reticular nucleus
Ls short muscle length
LSD least significant difference (test) or lysergide
LSO lateral superior olives
LT lactate threshold
LT-β lymphotoxin-β
LTB4 leukotriene B4
LTPA leisure time physical activity
LV left ventricular
LVC leg vascular conductance
LVdP systolic-diastolic ventricular pressure difference
LVdP/dtmax maximal positive value of first derivative of LV pressure
LVEF left ventricular ejection fraction
LVET left ventricular ejection time
LVO lung volume optimization
LVP left ventricular pressure
LVV left ventricular volume


m slope of linear change in mitochondrial conductance coefficient
m mass
μG microgravity
M molar = mol per liter
M Haldane coefficient, or relative affinity
«odot»M metabolic heat production
MAb monoclonal antibody
MABP mean arterial blood pressure
MAC minimum alveolar concentration
mAChR muscarinic acetylcholine receptor (bump R for receptor)
MACV minimum afferent conduction velocity
mA•h milliampere-hour
MAO monoamine oxidase
MAP mitogen-activated protein, or mean arterial pressure, or mean arterial blood pressure
MAPK mitogen-activating protein kinase, also MAPKK and MAPKKK (double and triple the "kinase" !)
MARCKS myristolated alanine-rich C kinase substrate
mATPase myofibrillar ATPase
Mb body mass
Mb myoglobin
MBED 9-methyl-7-bromoeudistomin D
MBF mesenteric blood flow
MBP mean blood pressure, or major basic protein
MBq mega becquerel (unit of measure, don't define)
MBW multiple-breath nitrogen washouts
MBWXe multiple-breath 133Xe washout
MCA middle cerebral artery
MCAO middle cerebral artery occlusion
MCC maternal cardiac complex
MCh methacholine
mCK mouse cytokine
MCK muscle creatine kinase
MCLA 2-methyl-6-(p-methoxyphenyl)-3,7-dihdroimidazo[,2-a]pyrazin-3-one hydrochloride
MCP musculocutaneous perforator
MCR metabolic clearance rate
MCSA muscle cross-sectional area
mCSF mock cerebrospinal fluid
MCV mean corpuscular volume
MDA malondialdehyde
MDH malate dehydrogenase
MDIBL Mt. Desert Island Biological Laboratory
MDR methacholine dose response
2-ME 2-mercaptoethanol
ME magnitude estimation
MEF-2 myocyte enhancer factor-2
MEFV maximal expiratory flow-volume
2-MeOE 2-methoxy estrogens
MEP maximal expired pressure, or mean expiratory mouth pressure
MEPP miniature end-plate potential
MES 2-(N-morpholino)ethanesulfonic acid
2-MeS-ATP 2-methylthio-ATP
MET metabolic equivalent [1 MET = 3.5 ml•kg1•min1 (oxygen consumption at rest)]
MFA muscle fiber area
MFI mean fluorescence intensity
MG macroglycogen, or medial gastrocnemius, or marginal glia
3-MG 3-O-[ 3H]methyl-d-glucose
MHC myosin heavy chain (MHCneo, slow, 1, 2A, 2X, 2B, ; MHC IIa, MHC IIx, etc.)
MHS muscle histopathology score
MI myocardial infarction
MID multiple-indicator dilution
MIF migration inhibition factor, or maximal isometric force
MIGET multiple inert-gas elimation technique
MIMS membrane inlet mass spectrometry
MIP major intrinsic protein, or mean inspiratory mouth pressure
MIP-1α macrophage inflammatory protein (also -1, -1β)
MIWC mercurial-insensitive water channel
MKK4 mitogen-activated protein kinase kinase 4
MLD mean lung density
mM millimolar per liter (mmol/l is OK)
MMAD mass median aerodynamic diameter
MMC migrating motor complex
mmHg millimeters of mercury (do not define)
MMIMS micropore membrane inlet mass spectrometry
MMLV Moloney murine leukemia virus
MMP matrix metalloproteinases (MMP-1, etc.)
MMW medium molecular weight
mo month
MOAT multispecific organic anion transporter
mol mole (do not define)
MOPS 3-(N-morpholino)propanesulfonic acid
MNS modified natural surfactant
mol wt molecular weight (do not define)
M«phi» macrophage
MPAP mean pulmonary arterial pressure
mph miles/hour (must define as mile/h)
MPO myeloperoxidase
MPWC maximal physical working capacity
MR magnetic resonance
Mr molecular ratio (mass)
MRI magnetic resonance imaging
MRS magnetic resonance spectroscopy
MRT mean response time
MSAP mean systemic arterial pressure
MSD membrane-spanning domain
MSH melanocyte-stimulating hormone
MSNA muscle sympathetic nerve activity
MSO medial superior olives
MTA moving time average
mtDNA mitochondrial DNA
mTe mechanical expiratory time
mTi mechanical inspiratory time
mtTFA mitochondrial transcription factor A
MVC maximum voluntary contraction
MVIC maximum volitional isometric contraction
M«vo2» myocardial O2 consumption
MVP mean venous pressure
MVV maximal voluntary ventilation
MVV15 maximal voluntary ventilation in 15 s
MW molecular weight (not APS style - use mol wt instead)
MWC maximal work capacity
m/z mass-to-charge ratio
MZ methazolamide


N nondeposited fraction of gas or nitrogen
NA nucleus ambiguus, numerical aperature or not available, not applicable (esp. in tables)
NAC N-acetyl-l-cysteine
NaCN sodium cyanide (do not define)
NADPH reduced NADP
NAF non-anticoagulant fractions
NANC nonadrenergic noncholinergic
NAP neutrophil-activating peptide
NBD nitrobenzoxadiazole (e.g., NBD-phallacidin), or nucleotide-binding domain (NBD1, NBD2, etc.)
NBHR nonbronchohyperresponsive
NBT nitro blue tetrazolium (dye)
NC normocholesterolemia
NCS neonatal calf serum
ND standard optics symbol for index of refraction
ND nandrolone decanoate or not defined, not determined
NDGA nordihydroguaiaretic acid
NDI nephrogenic diabetes insipidus
NDM nasal dilator muscle
NE norepinephrine, or nuclear extracts, or normalized elastance
NECA 5´-(N-ethylcarboxamido)adenosine
NEFA nonesterified fatty acids
NEM N-ethylmaleimide
NEP neutral endopeptidase, or negative expiratory pressure
NEX number of excitations
NF-κB nuclear factor-κB, NEW: insert hyphen-
NGF nerve growth factor
nH Hill coefficient
NHE Na+/H+ exchanger (NHE1, NHE2, NHE3... some authors will hyphenate; use author preference)
NHS normal horse serum
NIDDM non-insulin-dependent diabetes mellitus
NIPS News Physiol. Sci.
NIRS near-infrared spectroscopy
NK1, NK2, etc. neurokinin receptors
NKA neurokinin A
NKB neurokinin B
NKCA natural killer cell activity
NLA nitro-l-arginine
NMDA N-methyl-d-aspartate
NMJ neuromuscular junction
NMP N-methyl-2-phenylindole
NMR nuclear magnetic resonance
NO nitric oxide (do not define)
NOS nitric oxide synthase (NOS II, NOS III; also ecNOS, nNOS, iNOS... see iNOS)
NP-40 Nonidet P-40
NPR natriuretic peptide receptor (NPR-A, -B, -C) also called GC-A and GC-B (for guanylyl cyclase)
NPY neuropeptide Y
NR normalized resistance
NREM non-rapid eye movement (do not hyphenate "rapid eye movement" when used as an adjective)
NRP nucleus reticularis pontis
NRti normalized tissue resistance
NSAID nonsteroidal anti-inflammatory drugs
NSC nonspecific cation
NSILA nonsuppressive insulin-like activity
NSP nonstarch polysaccharides
NSR noise-to-signal ratio
nt nucleotide
NTCP Na+-taurocholate-cotransporting polypeptide
NTS nucleus tractus solitarii (nucleus of solitary tract)
NUAP negative upper airway pressure


O3 ozone (do not define)
«o2» superoxide anion (do not define)
«o2rad» superoxide anion radical
OA ovalbumin
OC osteocalcin
OCDP optimal continuous distending pressure
OCT optimum (optimal) cutting temperature
OD optical density
ODC O2 dissociation curve of Hb
ODF occurrence density function
2-OG 2-oxoglutarate
OGF opioid growth factor
«radoh» hydroxyl radical (do not define)
3-OHB 3-hydroxybutyrate
8-OH-DPAT 8-hydroxy-2(di-n-propylamino)tetralin
2-OHE 2-hydroxyestrogens
O2p O2 pulse
OPG oligophoglycerate
OR odds ratios
ORAC oxygen radical absorbance capacity
ORS oxygen-reactive species or ROS, reactive oxygen species
OSA obstructive sleep apnea
OSAS obstructive sleep apnea syndrome
OVA ovalbumin
OVLT organum vasculosum laminae terminalis
Ovx oophorectomized
OVX ovariectomy, or ovariectomized
oxo8dG 8-hydroxy-2´-deoxyguanosine


π oncotic pressure
p Laplace transform variable
p para (precedes a chemical name)
P permeability, or probability, or perimeter
P pressure, or force, or tension, or polarization
P0.1 mouth pressure 100 ms after beginning of inspiratation
P1 pellet fraction
P1, P2, P3, etc. promotor regions of genes
P2 purinoreceptors (P2x, excitatory; P2y, inhibitory)
P50 O2 concn required for half-maximal reduction, or «po2» necessary to obtain 50% O2 saturation of Hb, or O2 half-saturation pressure
P300 long-latency potential brain wave
Pa arterial partial pressure
Pa alveolar pressure
PA phosphatidic acid, or puromycin aminonucleoside, or pulmonary artery
PAC p-aminoclonidine , or plasma aldosterone concentration
«paco2» arterial partial pressure of CO2 (measured in Torr; JAP-specific)
Palb diffusional permeability to albumin
Pam ambient pressure
Pao airway opening pressure
«pao2» arterial partial pressure of O2 (measured in Torr)
PACAP pituitary adenylate cyclase-activating polypeptide
PACAP-38 or range PACAP-(17«sbond»38)
PAE postanodal excitation
PAF platelet-activating factor
Pa{↓N2} partial pressure of N2 in arterial blood
Pao airway opening pressure
PAS periodic acid Schiff (staining)
Pa{↓SF6} partial pressure of SF6 in alveoli
Patm atmospheric pressure
PAV proportional-assist ventilator
Paw airway pressure
Ppaw pulmonary arterial wedge pressure
Pb barometric pressure
PBF pulmonary blood flow
PBL parabrachialis lateralis
PBM parabrachialis medialis
P{↓b|N2} pressure of N2 inside bubble
Pbox box pressure
Pbr bronchial pressure
PC phosphatidylcholine, or provacative concentration, or principal component
PC20 concn. of [drug] that induces 20% decline in FEV1
pCa pH of calcium (do not define)
pCa50 –log Ca50 (do not define)
PCA postconceptional age, or perchloric acid, or posterior cricoarytenoid
PCF pressure correlation function
PC+M palmitoyl-dl-carnitine + malate
PCNA proliferating cell nuclear antigen
«pco2» CO2 tension either venous or arterial (in Torr, no need to define)
pCPA p-chlorophenylalanine methyl ester hydrochloride
Pc{↓O2} partial pressure of O2 in capillary blood
PCr phosphocreatine
PCR polymerase chain reaction
Pcrit critical pressure
Pcuff cuff pressure
PCWP pulmonary capillary wedge pressure
Pcyl cylinder pressure
pD2 apparent affinity
PD20 provocative dose that causes 20% decline in FEV1
PDB-1 Pee Dee Belemnitella-1
PDBu phorbol 12,13-dibutyrate
PDE phosphodiesterase (see sheet on this family)
PD-ECGF platelet-derived endothelial cell growth factor
PDF probability density function
PDGF platelet-derived growth factor (B, -β)
PDH pyruvate dehydrogenase
Pdi transdiaphragmatic pressure
Pdipls transdiaphragmatic pressure in pulse breaths
Pdi,tw transdiaphragmatic pressure twitch
Pdx|70 diffusional permeability to dextran 70
Pe equilibrium pressure
Pe Péclet number
PE phosphatidylethanolamine, or phycoerythrin, or phenylephrine
Pe expiratory pressure
«obar»Pe mean pressure developed during expiration
PEC peritoneal exudate cell
PECAM-1 platelet endothelial cell adhesion modecule 1
PEEP positive end-expiratory pressure
PEEPi intrinsic positive end-expiratory pressure
PEF peak expiratory flow
Peff effective positive pressure
PEG polyethylene glycol
Pemax maximum exspiratory pressure
Penh enhanced pause
PEP preejection period
PERCP peridinin-chlorophyll-a-protein
PerCP peridinin chlorophyll protein
Pes esophageal pressure
PET positron emission tomography
«petco2» end-tidal «pco2»
Pes esophageal pressure, or end-systolic pressure
Pes,tw esophageal pressure twitch
PET plethysmograph/exposure tube
Pexp expiratory pressure
PF peak tetanic force
PFC perfluorocarbon, or perfluorochemical
PFK-2 phosphofructokinase-2
PFO patent foramen ovale
PFT pulmonary function test
PFU plaque-forming unit
PG proteoglycans, or proglycogen, or phosphatidylglycerol
Pga gastric pressure
PGAM phosphoglycerate mutase
Pgas gas pressure
Pga,tw gastric pressure twitch
PGCL paragigantocellularis lateralis
Pg{↓CO2} gastric «pco2»
PGE1 prostaglandin E1
PGO pontogeniculooccipital
PH prolyl-4-hydroxylase, or pulmonary hypertension, or phrenic nerve
PHA phytohemagglutinin
PHG-CA posthandgrip circulatory arrest
PHI peptide histidine-isoleucine amide (Bachem: a string of amino acids from his to iso
therefore hyphenate)
PHIGS Programmer's Hierarchical Interactive Graphics System
pHi intracellular pH
Ph2o partial pressure of water vapor
PHM peptide histidine-methionine
Pi inorganic phosphate (do not define)
pI isoelectric point
PI phosphatidylinositol
Pi inspiratory pressure
«obar»Pi mean pressure developed during inspiration
PIA N6-phenylisopropyl adenosine, or N6-(2-phenylisopropyl)adenosine (note: R-PIA and S-PIA are (+) and (-) isomers)
PiCO partial pressure of inhaled carbon monoxide
«obar»Pi + e mean pressure developed during whole breathing cycle
pIgR polymeric immunoglobulin receptor
PI3-kinase phosphatidylinositol 3-kinase
Pim intramuscular pressure
Pimax maximum inspiratory pressure
«pio2» inspired «po2»
PIP peak inspiratory pressure
PIP2 phosphatidylinositol 4,5-bisphosphate
PIPES piperazine-N,N´-bis(2-ethanesulfonic acid)
PIRE percent increase ratio of El
PIRR percent increase ratio of Rl
Pitr intratracheal pressure
PK perilla ketone
pKa acidic dissociation constant
pKb negative log of equilibrium constant
PKC protein kinase C
Pkelvin kelvin body pressure
PL phospholipid
Pl transpulmonary pressure or pulmonary pressure
Pla left atrial pressure
↑Pla increased left atrial pressure
PLC phospholipase C (also PLCγ)
PlFRC transpulmonary pressure at functional resisdual capacity
PLSD paired least significant difference
PLV partial liquid ventilation
Pm mouth pressure
P+M pyruvate + malate
PMA phorbol 12-myristate 13-acetate (same as TPA)
Pmask mask pressure
PME phosphomonoesters
pMG proximal medial gastrocnemius
PMN polymorphonuclear neutrophils (leukocytes)
PMSF phenylmethylsulfonyl fluoride
Pmv microvascular pressure
PNA postnatal age, or phrenic nerve activity, or phrenic nerve amplitude
Pns nostril pressure
PNU protein nitrogen units
31P-NMR 31P nuclear magnetic resonance
P0 initial pressure
Po outflow pressure, or maximum isometric force, or maximal tetanic force
po per os, i.e., by mouth (cf. iv, ip)
«po2» partial O2 pressure or O2 tension (in JAP: measured in Torr, do not define)
Po2|crit critical «po2»
POAH preoptic/anterior hypothalamic region of the brain stem, or preoptic area of the anterior hypothalamus
POMC proopiomelanocortin
POPE palmitoyl-oleoyl-phosphatidylethanolamine
POPS palmitoyl-oleoyl-phosphatidylserine
Posmol plasma osmolality
Ppa pulmonary arterial pressure (not artery)
PPARα peroxisome proliferator-activated receptor-α
ppb parts per billion
PPHN persistent pulmonary hypertension of the newborn
Ppi pulmonary inflation pressure
Ppl pleural pressure, or intrapleural pressure
ppm parts per million
P/Po relative tension
Ppv pulmonary venous pressure
pQCT peripheral quantitative computerized tomography
PRA plasma renin activity
pRc peripheral chemoreceptor
pre-BötC pre-Bötzinger complex
Pres resistive pressure
[Pro]tot total protein concn
PS phosphatidylserine
PS permeability-surface area product
Psa systemic arterial pressure
Psl{↓CO2} sublingual «pco2»
PSP pancreatic spasmolytic peptide
PSR pulmonary stretch receptor
PSS physiological salt solution
Pt peak twitch force or maximal twitch force
PT pneumotachography
PTCER pulmonary transcapillary escape rate
Ptc{↓CO2} transcutaneous CO2 tension
PTFE polytetrafluoroethylene
PTH parathyroid hormone
PTHRP parathyroid hormone-related protein
PTI pressure-time integral
Pti{↓CO2} tissue «pco2»
Pti{↓H2O} partial pressure of H2O in tissue
Pti{↓O2} tissue «po2»
PTK protein tyrosine kinases
Ptp transpulmonary pressure
Ptr tracheal pressure
PTX pertussis toxin, or parathyroidectomized, parathyroidectomy
PTZ pentylenetetrazole
PUFA polyunsaturated fatty acids
P«obar»v mixed venous partial pressure
P-V pressure-volume (always hyphenate acronym)
PVBFV portal venous blood flow velocity
PVC polyvinyl chloride
«pvco2» venous «pco2»
PVDF polyvinylidene difluoride
PVH periventricular hypothalamus
«pvo2» venous «po2»
P«obar»v{↓O2} mixed venous «po2»
PVR pulmonary vascular resistance
PVRI pulmonary vascular resistance index


«odot»Q blood flow, cardiac output
«odot»Qaw airway mucosal blood flow
«odot»Qc cardiac output
Q10 temperature coefficient amount of change in rate of a chemical reaction for a 10°C change in temperature, or effect of 10°C change on metabolism (do not define)
«odot»Qha hepatic artery blood flow
«odot»Ql lymph flow
Qmax maximum rate of ATP production
«odot»Qnsc nasal superficial capillary blood flow
«odot»Qpa arterial plasma flow
«odot»Qpv portal vein blood flow
Qs/Qt inert-gas shunt
QTL quantitative trail loci


ρ density
ρ{↓O2} molecular density of O2
r correlation coefficient
R side chain (in atoms), or gas constant, or resistance, or pulmonary/tissue retention
R resistance (electrical)
R0 resistance at 0 frequency (pulmonary)
R«infinity» resistance at infinite frequency (pulmonary)
Ra rate of appearance
RAAS renin-angiotensin-aldosterone system
RACE rapid amplification of cDNA ends
RANTES regulated on activation normal T-expressed and presumably secreted
RAP respiratory aerosol probe, or right atrial pressure
RAR rapidly adapting receptor
RAS renin-angiotensin system
Raw airway resistance
RBC red blood cells ("red cell" as adjective is okay)
RBF renal blood flow
RC rib cage
rCBF regional cerebral blood flow
RCM rib cage muscles
r{↓CO2} rate of CO2 production
RCR respiratory control ratio
Rd rate of disappearance
RD regulatory domain, or rate of twitch tension development
RDA recommended dietary allowance
RDS respiratory distress syndrome
rENaC rat epithelial Na channels
RE resistance of extracellular water
Reff effective resistance of the lung
REM rapid eye movement (do not hyphenate as adjective)
RER respiratory exchange ratio
Rexp expiratory circuit resistance
Rf relative migration, or retardation factor (in chromatography - do not define)
RF radio frequency, or rectus femoris, or rise fraction
RFN retrofacial nucleus
Rg glucose metabolic index
RGB red, green, blue (standard usage in video industry - do not define)
rG-CSF recombinant granulocyte colony-stimulating factor
RGM respiratory gas analyzer
RH relative humidity
RHBF reactive hyperemic blood flow
rhGRF rat hypothalamic hormone- releasing factor
RI inspiratory resistance
RIA radioimmunoassay
RIP respiratory inductive plethysmograph
Rl total lung resistance, or pulmonary resistance, or lung resistance
RL,E expiratory pulmonary resistance
RL,I inspiratory pulmonary resistance
RLN recurrent laryngeal nerve
RLS recursive least squares
RM raphé magnus
1 RM one repetition maximum
RMP resting membrane potential
RMR resting metabolic rate
RMS root mean square
RNS reactive nitrogen species
Rn nasal resistance
rn fraction of bound sites at end of nth recovery interval
RO raphé obscurus
ROD relative optical density
ROI region of interest
ROM range of angular motion
ROO«rrad» peroxyl radical
ROS reactive oxygen species
RP raphé pallidus
Rp-cAMP[S] Rp-adenosine 3´,5´-cyclic monophosphorothioate
Rpa peripheral airway resistance
RPA RNase protection assay
RPBF relative pulmonary blood flow
RPE rating of perceived exertion
R-PE R-phycoerythrin
RPMI 1640 (growth medium; stands for Roswell Park Memorial Institute - do not define)
RPO rostral periolivary region
RPP rate-pressure product
RQ respiratory quotient
R-R R-wave-R-wave (interval)
RR rate of twitch tension relaxation
RREP respiratory-related evoked potential
Rrs respiratory system resistance
RSA respiratory sinus arrhythmia
RSNA renal sympathetic nerve activity
RSS residual sum of squares
RSSE residual sum of squared errors
RT transepithelial resistance
RTE transepithelial electrical resistance
RT reverse transcriptase, or resistance training (do not define)
RT1/2 one-half relaxation time
RT50 half relaxation time
Rti tissue resistance
Rti, l lung tissue resistance
RTM resting twitch moment
RTN retrotrapezoid nucleus
RT-PCR reverse transcriptase-polymerase chain reaction
RTS reconstituted test surfactants
Ruaw upper airway wall resistance
Rv vascular resistance
RV residual volume
RVD restrictive ventilatory disease
RVLM rostral ventrolateral medulla
rVMS rostral ventrolateral medullary surface
RVR renal vascular resistance
rVRG rostral ventral respiratory group
RyR ryanodine receptor (RyR1, RyR2)


σ reflection coefficient
σg geometric SD
S slope, or surface area
S-A sinoatrial
SAAT subcutaneous abdominal adipose tissue
SAGE serial analysis of gene expression
SAH S-adenosylhomocysteine hydrolase
SAHS sleep apnea hypopnea syndrome
SAN sinoatrial node
«sao2» arterial O2 saturation
SAP systolic arterial pressure, or systemic arterial pressure
SAPI spatial average pixel intensity
SAR specific absorption rate, or slowly adapting receptors
SAV small-animal ventilator
SBFI sodium-binding benzofuran isophthalate
SBN single-breath nitrogen (test)
SBT single-breath test
SBTI soybean trypsin inhibitor
SBW single-breath washout
sc subcutaneous
SCF stem cell factor
SCI spinal cord injury
SCP static condition period
SD standard deviation
SD50% SD at 50%
SDH succinate dehydrogenase
SDNN SD of normal R-R intervals
SDP standard deviation plotting
SD«odot»Q SD of perfusion distribution
SDS sodium dodecyl sulfate
SDS-PAGE sodium dodecyl sulfate-polyacrylamide gel electrophoresis (do not define)
SE standard error, or sympathoexcitatory
SEE standard error of estimate
SEP somatosensory-evoked potentials
SERCA sarco(endo)plasmic reticulum Ca2+-ATPase (e.g., SERCA2) (SERCA1 gene)
SET standardized exercise test
Sf Svedberg units
SF6 sulfur hexafluoride
SFO subfornical organ
SFR short-latency fractionation response
sGaw specific airway conductance
SHBG sex hormone-binding globulin
SHR spontaneously hypertensive rat
SI sympathoexcitatory, or spectroscopic imaging
SIN-1 3-morpholinosydnonimine
SIRS systemic inflammatory response syndrome
SITS 4-acetamido-4´-isothiocyanostilbene-2,2´-disulfonic acid
SkBF skin blood flow
SL sarcolemmal, or sea level
SLeX sialyl Lewis X-like carbohydrates
slm stratum lacunosum moleculare
SLNin internal branches of superior larengeal nerve
sm stratum moleculare
SMA supplementary motor area, or superior mesenteric artery
smg small molecular weight GTP-binding protein
SN sinus node, or signal to noise, or substantia nigra
SNA sympathetic nerve activity
SNAP S-nitroso-N-acetyl-penicillamine or soluble NSF-associated protein (NSF = N-ethylinaliemide-sensitive factor), or synaptosomal-associated protein
SNO-Hb S-nitrosohemoglobin
SNP sodium nitroprusside
SNR signal-to-noise ratio
SNS sympathetic nervous system
So2 oxyhemoglobin saturation
SOC self-organized criticality
SOD superoxide dismutase
Sol soleus
SON supraoptic nucleus
SP-A surfactant protein A
sp act specific activity
SP-cAMP[S] stimulatory diastereoisomer of adenosine 3´,5´-cyclic monophosphate
SPECT single-photon-emission computed tomography
SPF specific-pathogen free
sPLA2 secreted phospholipase A2
SPM statistical parametric mapping
Sp{↓O2} arterial O2 saturation from pulse oximetry
8-SPT 8-(p-sulfophenyl)-theophylline
SR sarcoplasmic reticulum, or sweat rate
sRaw specific airway resistance
SRE serum response element (SRE1, SRE2, SRE3)
SRF serum response factor
SRIF somatotropin release-inhibiting factor
sRl specific pulmonary resistance
SRT spinoreticular tract
SSC sodium chloride-sodium citrate, or standard sodium citrate, or saline sodium citrate (do not define)
SSD sum of squares of differences
SSI strength strain index
SSLP simple sequence-length polymorphism
SSNA skin sympathetic nerve activity
SSPE sodium chloride-sodium phosphate-EDTA
SSRE shear stress-response element
STAT signal transducer and activator of transcription
STPD standard temp. pressure dry (do not define)
STT spinothalamic tract
STZ streptozotocin
Sv capillary surface area
SV stroke volume
SVI stroke volume index
SVmax maximal stroke volume
SVOP system for venous occlusion plethysmography
SVR systemic vascular resistance
SVRI systemic vascular resistance index
SWIFT sine wave inspiratory forcing technique
SWS slow-wave sleep


τ time constant
ΘCO CO uptake conductance of erythrocytes
t time
t1/2 half-time
T1 longitudinal relaxation time
T2 transverse relaxation time
T3 3,5,3´-triiodothyronine
T4 thyroxine
T84 cell line
T temperature, or tension
T thickness
Ta ambient temperature
ta interval during which drug binds
TA thoracic aorta or thyroarytenoid
TAB total autonomic blockade
TAC total antioxidant capacity
TAG triacylglycerol
TAME Nα-p-tosyl-l-arginine methyl ester
TAN total adenine nucleotide
TAV total angle variance
Tb body temperature
«obar»Tb mean body temperature
TBA thiobarbituric acid
TBARS thiobarbituric acid-reactive substances
TBK total body potassium
TBS Tris-buffered saline
TBW total body water
Tc body core temperature
99mTc technetium-99m
TCA trichloroacetic acid or tricarboxycylic acid
TCr total creatine
TCVP transmural central venous pressure
Td time delay
TD time delay or tissue density
TD50 time to reach 50% decay
Te expiratory time, or duration of expiration
TE Tris-EDTA buffer, or echo time
TEA tetraethylammonium or thermic effect of activity
TEAC trolox equivalent antioxidant capacity
TEAM external auditory meatus temperature
TEAP tetraethylammonium phosphate
TEE transesophageal echocardiography, or total energy expenditure
TEeff effective echo time
TEER transepithelial electrical resistance
TEF thermic effect of food
TEM transmission electron microscopy, or technical errors of measurement
TEMED N,N,N´,N´-tetramethylethylenediamine
TER transcapillary escape rate or total energy requirement or transendothelial electrical resistance
Tes esophageal temperature
TF transfer function
TFA trifluoracetic acid or transcription factor A
TFW tendon fluid weight
TG triglycerides, or thioglycolate
TGF-β,-β1, -α transforming growth factor-β, etc. TGF can also be tubuloglomerular flow
TGLP truncated form of GLP lacking the 6 NH2-terminal amino acid sequence
TGSH total glutathione
TGV thoracic gas volume
Th T helper (Th1, Th2)
tHb total Hb
THF tetrahydrofolate
Ti inspiratory time, or duration of inspiration
Ti/Tt respiratory duty cycle
TIU trypsin inhibitor unit
TKRA tachykinin receptor antagonist
TLC thin-layer chromatography, or total lung capacity
Tlim time limit of endurance
Tloc local temperature at LDF measurement site
TLV total liquid ventilation
Tm muscle temperature
TMA tetramethylammonium
Tmax maximal torque
TMPD tetramethylpentadecane
TnC troponin C
TnCf troponin C fast isoform
TnCs troponin C slow isoform
TNF tumor necrosis factor
TNF-α tumor necrosis factor-α
TNFR1 TNF receptor 1
TNI tonic neural input
TNT 2,4,6-trinitrotoluene
«odot»To2 convective O2 transport
«odot»To2|max maximum convective O2 transport
TPA 12-O-tetradecanoylphorbol 13-acetate (same as PMA)
Tpa pulmonary artery temperature
TPCK N-tosyl-l-phenylalanine chloromethyl ketone
TPOAH temperature of the preoptic-anterior hypothalamic region of the brain stem
TPR total peripheral resistance
TPTZ tripyridyltriazine
tr interval during which drug is trapped
Tr repetition time
TR transverse relaxation time, or time resolved, or repetition time
TRAP thrombin receptor agonist peptide
Tre rectal temperature
TRIP thrombin receptor inhibitor peptide (may be several)
Tris tris(hydroxymethyl)aminomethane (do not define)
TRITC tetramethylrhodamine isothiocyanate
Tset set-point temperature
Tsk skin temperature
«obar»Tsk mean skin temperature
Tsl sublingual temperature
TSGG transsarcolemmal glucose gradient
TSH thyrotropin, or thyroid-stimulating hormone
Tt total breath time
TT transit time
Ttot duration of respiratory cycle
TTtot total tension time
TTBS Tween-20 Tris-base sodium
TTC triphenyltetrazolium chloride
TTE transthoracic contrast echocardiography
TTF-1 thyroid transcription factor-1
TTI tension-time integral
TTL transistor-transistor logic
TTX tetrodotoxin
TVR tonic vibration reflex
Tx thromboxane (TxA, TxB)
TxA2 thromboxane A2


U RF excitation voltage
UAW upper airway
UCP uncoupling protein
ULMW ultralow molecular weight
UN urea nitrogen
UNDW ultrasonically nebulized distilled water
[UMI] unmeasured ion concn
URPmax maximum vascular conductance
URTI upper respiratory tract infection
USF upstream stimulatory factor
USL unstirred layer
UTP (do not define)
UTR untranslated region
UV ultraviolet


«odot»V flow, or ventilation
1/«odot»V reciprocal of gas flow through nose
v exponential rate constant, or velocity, or voltage (potential)
V volt (keV = kilo-electron volt), or volume, or PCr resynthesis rate
V potential, or velocity, or voltage
Va apical membrane voltage
«odot»Va alveolar ventilation
(v-a)CO2 venoarterial CO2 concentration difference
VAH ventilatory acclimatization to hypoxia
VAMP vesicle-associated membrane polypeptide
(v-a)«pco2» venoarterial «pco2» difference
«vaq» ventilation-perfusion
VAS visual analog scale
Vb basolateral membrane voltage
V{↓b|N2} volume of N2 in bubble
Vc capillary volume, or pulmonary capillary blood volume
Vc command potential
Vc centerline blood flow velocity
«odot»Vc central component of ventilation
VC vital capacity
VCAM-1 vascular cell adhesion molecule 1
«odot»Vco carbon monoxide production
«odot»Vco2 carbon dioxide production
VD volume of distribution
Vd dead space volume
Vdanat anatomic dead space volume
VDCC voltage-dependent calcium channels
Vdphys physiological dead space volume
Ve voltage electrodes
«ve» minute ventilation
«ve» max maximal exercise ventilation
«odot»VE exhalation flow rate
«ve»crit critical «ve»
Ved end-diastolic volume
VEGF vascular endothelial growth factor (rhVEGF, for recombinant human)
Ves end-systolic volume
VF ventricular fibrillation
VFD volumetric front depth
VH vascular hypoxia
«vi» inspiratory flow, inspired minute ventilation
Vi initial volume
VIF variance inflation factor
«odot»Vimax maximal inspiratory flow
«odot»Vin inflow
Vmax maximum PCr recovery rate
«odot»Vout outflow
VOI volume of interest
VIP vasoactive intestinal peptide
Vl breath-holding volume, or lung volume
VL vastus lateralis
VLD volumetric lung depth
VLDL very low-density lipoprotein
VLl left lung volume (VLleft preferred)
VM vastus medialis
«odot»Vmax maximal expiratory flow
Vmax maximal velocity, or maximum velocity, or maximum rate of transition (do not define)
Vmean mean blood cell velocity
VMH ventromedial hypothalamus
VMS ventrolateral medullary surface
VNA vertebral nerve activity
«odot»VnE gas flow out of nose (expiration)
«odot»VnI gas flow into nose (inspiration)
«odot»Vno NO production
V0 unloaded shortening velocity, maximal shortening velocity
«vo2» oxygen consumption
«odot»Vo2|max maximal oxygen consumption
«odot»Vo2|rm O2 consumption by respiratory muscles
«odot»Vo2|tot total body O2 uptake
«odot»Vo2|tot,|max maximal total body O2 uptake
VOP venous occlusion plethysmography
Vp penetration volume, or volumetric penetration
«odot»Vp perpheral component of ventilation
Vp|250 volumetric penetration of 250 ml
VPS vinyl polysiloxane
VPF vascular permeability factor
VPS ventral pontine surface
Vr erythrocyte velocity
Vr residual volume
VRG ventral respiratory group
«odot»Vs sample flow rate
VT ventricular tachycardia, or ventilatory threshold
Vt tidal volume
Vtabd abdominal compartmental ventilation
Vti volume of neural tissue, or tissue volume
VtPT tidal volume obtained from PT
«odot»Vtrc rib cage compartmental ventilation
Vtrip tidal volume estimates of the RIP
Vt transepithelial voltage
Vv volume density
Vv(mt,f) mitochondrial volume density
Vvp volume density of parenchyma
Vvr volume density of respiratory region
Vvra volume density of respiratory air spaces
Vvrt volume density of respiratory tissues
Vw leukocyte velocity


W work per breath
«odot»W work rate, power, respiratory power
«odot»Wmax maximal external power
W0 wet weight
W-7 N-(6-aminohexyl)-1-naphthalenesulfonamide
Wb work of breathing
WB whole body
WBC white blood cell
WCH-CD water channel-collecting duct channel
WDR wide dynamic range
We work done during expiration
Wg´ compressibility of alveolar gas
WGA wheat germ agglutinin (e.g., WGA-Sepharose)
Wi mechanical work done during inspiration
Wi + e mechanical work done during breathing cycle
WL workload
WLW wet lung weight
WOB work of breathing
WPI World Precision Instruments
WRmax maximum work rate
Wrs work of breathing
«odot»Wrs mechanical power of breathing


X X chromosome
X aspect ratio
x-axis horizontal axis (absicca)
XAC xanthine amine congener
XD xanthine dehydrogenase
XIP exchange inhibitory peptide
Xl lung reactance
Xn nasal reactance
XO xanthine oxidase
Xp parallel reactance
Xrs respiratory system reactance
Xuaw upper airway wall reactance


Y Young's modulus
y-axis vertical axis (ordinate)
YY1 yin yang 1


z ion valence
Z pulmonary/tissue impedance
Z impedance (electrical)
Z0 thoracic impedance
Zbox box impedance
Zcw chest wall impedance
ZEEP zero end-expiratory pressure
ZFP zero-flow pressure
Zl lung impedance
ZMP 5-aminoimidazole-4-carboxamide-1-β-d-ribofuraosyl 5´-monophosphate
Zn nasal impedance
ZnDPBG zinc deuteroporphyrin 2,4-bis glycol
Zp pneumotachograph impedance
Zrs respiratory system impedance
Zuaw upper airway wall shunt impedance
Zw chest wall impedance

home » resources »

last edited 08/14/03