Dibenzo[a,h]anthracene (T3D0015)

IdentificationTaxonomyBiological PropertiesPhysical PropertiesToxicity ProfileSpectraConcentrationsLinksReferencesGene RegulationTargets (7)XML
Targets (7)
Record Information
Version2.0
Creation Date2009-03-06 18:57:55 UTC
Update Date2014-12-24 20:20:52 UTC
Accession NumberT3D0015
Identification
Common NameDibenzo[a,h]anthracene
ClassSmall Molecule
DescriptionDibenzo(a,h)anthracene is one of over 100 different polycyclic aromatic hydrocarbons (PAHs). PAHs are chemicals that are formed during the incomplete burning organic substances, such as fossil fuels. They are usually found as a mixture containing two or more of these compounds. It is one ingredient of cigarette. (4)
Compound Type
  • Aromatic Hydrocarbon
  • Cigarette Toxin
  • Food Toxin
  • Industrial By-product/Pollutant
  • Industrial/Workplace Toxin
  • Natural Compound
  • Organic Compound
  • Pollutant
  • Polycyclic Aromatic Hydrocarbon
Chemical Structure
Thumb
MOLSDFPDBSMILESInChI
Synonyms
Synonym
1,2,5,6-Dibenzanthracene
1,2:5, 6-Dibenzanthracene
1,2:5,6-Benzanthracene
1,2:5,6-Dibenz(a)anthracene
1,2:5,6-Dibenzanthracene
1,2:5,6-Dibenzoanthracene
Benzo[k]tetraphene
Benz[a,h]anthracene
DBA
Dibenz(a,h)anthracene
Dibenz(a,h)antracene
Dibenzathracene
Dibenza[a,h]-anthracene
Dibenzo(a,h)anthracene
Dibenzo[a,H]anthracene
Dibenz[a,H]anthracene
Chemical FormulaC22H14
Average Molecular Mass278.347 g/mol
Monoisotopic Mass278.110 g/mol
CAS Registry Number53-70-3
IUPAC Namepentacyclo[12.8.0.0^{3,12}.0^{4,9}.0^{15,20}]docosa-1,3,5,7,9,11,13,15,17,19,21-undecaene
Traditional Namepentacyclo[12.8.0.0^{3,12}.0^{4,9}.0^{15,20}]docosa-1,3,5,7,9,11,13,15,17,19,21-undecaene
SMILESC1=CC=C2C(C=CC3=CC4=C(C=CC5=CC=CC=C45)C=C23)=C1
InChI IdentifierInChI=1S/C22H14/c1-3-7-19-15(5-1)9-11-17-14-22-18(13-21(17)19)12-10-16-6-2-4-8-20(16)22/h1-14H
InChI KeyInChIKey=LHRCREOYAASXPZ-UHFFFAOYSA-N
Chemical Taxonomy
Description belongs to the class of organic compounds known as phenanthrenes and derivatives. These are polycyclic compounds containing a phenanthrene moiety, which is a tricyclic aromatic compound with three non-linearly fused benzene.
KingdomOrganic compounds
Super ClassBenzenoids
ClassPhenanthrenes and derivatives
Sub ClassNot Available
Direct ParentPhenanthrenes and derivatives
Alternative Parents
Substituents
  • Phenanthrene
  • Anthracene
  • Aromatic hydrocarbon
  • Polycyclic hydrocarbon
  • Unsaturated hydrocarbon
  • Hydrocarbon
  • Aromatic homopolycyclic compound
Molecular FrameworkAromatic homopolycyclic compounds
External Descriptors
Biological Properties
StatusDetected and Not Quantified
OriginExogenous
Cellular Locations
  • Membrane
Biofluid LocationsNot Available
Tissue LocationsNot Available
PathwaysNot Available
ApplicationsNot Available
Biological Roles
Chemical RolesNot Available
Physical Properties
StateSolid
AppearanceColorless solid.
Experimental Properties
PropertyValue
Melting Point269.5°C
Boiling PointNot Available
Solubility2.49e-06 mg/mL at 25 °C [HASSETT,JJ et al. (1980)]
LogPNot Available
Predicted Properties
PropertyValueSource
Water Solubility5.7e-07 g/LALOGPS
logP6.93ALOGPS
logP5.93ChemAxon
logS-8.7ALOGPS
Physiological Charge0ChemAxon
Hydrogen Acceptor Count0ChemAxon
Hydrogen Donor Count0ChemAxon
Polar Surface Area0 ŲChemAxon
Rotatable Bond Count0ChemAxon
Refractivity91.86 m³·mol⁻¹ChemAxon
Polarizability32.87 ųChemAxon
Number of Rings5ChemAxon
Bioavailability1ChemAxon
Rule of FiveYesChemAxon
Ghose FilterYesChemAxon
Veber's RuleYesChemAxon
MDDR-like RuleYesChemAxon
Spectra
Spectra
Spectrum TypeDescriptionSplash KeyDeposition DateView
Predicted GC-MSPredicted GC-MS Spectrum - GC-MS (Non-derivatized) - 70eV, Positivesplash10-004i-0090000000-81693ebd93637cbc70802021-09-23View Spectrum
Predicted GC-MSPredicted GC-MS Spectrum - GC-MS (Non-derivatized) - 70eV, PositiveNot Available2021-10-12View Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 10V, Positivesplash10-004i-0090000000-3115bf003b9cee6116092016-08-03View Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 20V, Positivesplash10-004i-0090000000-749c760f7a5a9c1aeeb02016-08-03View Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 40V, Positivesplash10-0fb9-0090000000-e058e0550d22fa7479e52016-08-03View Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 10V, Negativesplash10-004i-0090000000-773f4e4ef9823ddfdea32016-08-03View Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 20V, Negativesplash10-004i-0090000000-773f4e4ef9823ddfdea32016-08-03View Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 40V, Negativesplash10-004i-0090000000-910a1e5be083829e55352016-08-03View Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 10V, Positivesplash10-004i-0090000000-3ca26a652eff5433f50a2021-10-12View Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 20V, Positivesplash10-004i-0090000000-3ca26a652eff5433f50a2021-10-12View Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 40V, Positivesplash10-004i-0090000000-27ab7759f478445cae3f2021-10-12View Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 10V, Negativesplash10-004i-0090000000-f1f000ca3cb2151d263d2021-10-12View Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 20V, Negativesplash10-004i-0090000000-f1f000ca3cb2151d263d2021-10-12View Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 40V, Negativesplash10-0fb9-0090000000-46f199df2f90ecf72a7d2021-10-12View Spectrum
MSMass Spectrum (Electron Ionization)splash10-004i-0190000000-84d24efcba4eb6b8512e2014-09-20View Spectrum
1D NMR1H NMR Spectrum (1D, 90 MHz, CDCl3, experimental)Not Available2014-09-20View Spectrum
Toxicity Profile
Route of ExposureOral (4) ; inhalation (4)
Mechanism of ToxicityThe ability of PAH's to bind to blood proteins such as albumin allows them to be transported throughout the body. Many PAH's induce the expression of cytochrome P450 enzymes, especially CYP1A1, CYP1A2, and CYP1B1, by binding to the aryl hydrocarbon receptor or glycine N-methyltransferase protein. These enzymes metabolize PAH's into their toxic intermediates. The reactive metabolites of PAHs (epoxide intermediates, dihydrodiols, phenols, quinones, and their various combinations) covalently bind to DNA and other cellular macromolecules, initiating mutagenesis and carcinogenesis. The main carcinogenic metabolite of benzo(a)pyrene is the diol-epoxide trans-9,10-epoxy-7,8-dihydrodiol. (4, 5, 2, 3)
MetabolismPAH metabolism occurs in all tissues, usually by cytochrome P-450 and its associated enzymes. PAHs are metabolized into reactive intermediates, which include epoxide intermediates, dihydrodiols, phenols, quinones, and their various combinations. The phenols, quinones, and dihydrodiols can all be conjugated to glucuronides and sulfate esters; the quinones also form glutathione conjugates. (4)
Toxicity ValuesNot Available
Lethal DoseNot Available
Carcinogenicity (IARC Classification)2A, probably carcinogenic to humans. (6)
Uses/SourcesPAHs are released into the environment via the combustion of fossil fuels, coke oven emissions and vehicle exhausts, as well as naturally from forest fires and volcanic eruptions. PAHs from these sources may contaminate nearly water systems. They are also found in coal tar and charbroiled food. (4)
Minimum Risk LevelNot Available
Health EffectsPAHs are carcinogens and have been associated with the increased risk of skin, respiratory tract, bladder, stomach, and kidney cancers. They may also cause reproductive effects and depress the immune system. (4)
SymptomsAcute exposure to PAHs causes irritation and inflammation of the skin and lung tissue. (1)
TreatmentThere is no known antidote for PAHs. Exposure is usually handled with symptomatic treatment. (4)
Normal Concentrations
Not Available
Abnormal Concentrations
Not Available
DrugBank IDNot Available
HMDB IDNot Available
PubChem Compound ID5889
ChEMBL IDCHEMBL1346946
ChemSpider ID5678
KEGG IDC14325
UniProt IDNot Available
OMIM ID
ChEBI ID35299
BioCyc IDNot Available
CTD IDC026486
Stitch IDDibenzo[a,h]anthracene
PDB IDNot Available
ACToR ID412
Wikipedia LinkNot Available
References
Synthesis ReferenceNot Available
MSDST3D0015.pdf
General References
  1. Santodonato J, Howard P, Basu D: Health and ecological assessment of polynuclear aromatic hydrocarbons. J Environ Pathol Toxicol. 1981 Sep;5(1):1-364. [7310260 ]
  2. Uno S, Dragin N, Miller ML, Dalton TP, Gonzalez FJ, Nebert DW: Basal and inducible CYP1 mRNA quantitation and protein localization throughout the mouse gastrointestinal tract. Free Radic Biol Med. 2008 Feb 15;44(4):570-83. Epub 2007 Nov 12. [17997381 ]
  3. Padros J, Pelletier E: In vivo formation of (+)-anti-benzo[a]pyrene diol-epoxide-plasma albumin adducts in fish. Mar Environ Res. 2000 Jul-Dec;50(1-5):347-51. [11460716 ]
  4. ATSDR - Agency for Toxic Substances and Disease Registry (1995). Toxicological profile for PAHs. U.S. Public Health Service in collaboration with U.S. Environmental Protection Agency (EPA). [Link]
  5. Wikipedia. Benzopyrene. Last Updated 22 January 2009. [Link]
  6. International Agency for Research on Cancer (2014). IARC Monographs on the Evaluation of Carcinogenic Risks to Humans. [Link]
Gene Regulation
Up-Regulated Genes
GeneGene SymbolGene IDInteractionChromosomeDetails
Down-Regulated Genes
GeneGene SymbolGene IDInteractionChromosomeDetails

Targets

Target Details
1. Aryl hydrocarbon receptor
General Function:
Transcription regulatory region dna binding
Specific Function:
Ligand-activated transcriptional activator. Binds to the XRE promoter region of genes it activates. Activates the expression of multiple phase I and II xenobiotic chemical metabolizing enzyme genes (such as the CYP1A1 gene). Mediates biochemical and toxic effects of halogenated aromatic hydrocarbons. Involved in cell-cycle regulation. Likely to play an important role in the development and maturation of many tissues. Regulates the circadian clock by inhibiting the basal and circadian expression of the core circadian component PER1. Inhibits PER1 by repressing the CLOCK-ARNTL/BMAL1 heterodimer mediated transcriptional activation of PER1.
Gene Name:
AHR
Uniprot ID:
P35869
Molecular Weight:
96146.705 Da
Binding/Activity Constants
TypeValueAssay TypeAssay Source
AC500.07 uMATG_Ahr_CISAttagene
AC500.07 uMTox21_AhRTox21/NCGC
References
  1. Uno S, Dragin N, Miller ML, Dalton TP, Gonzalez FJ, Nebert DW: Basal and inducible CYP1 mRNA quantitation and protein localization throughout the mouse gastrointestinal tract. Free Radic Biol Med. 2008 Feb 15;44(4):570-83. Epub 2007 Nov 12. [17997381 ]
  2. Padros J, Pelletier E: In vivo formation of (+)-anti-benzo[a]pyrene diol-epoxide-plasma albumin adducts in fish. Mar Environ Res. 2000 Jul-Dec;50(1-5):347-51. [11460716 ]
  3. Xu H, Rajesan R, Harper P, Kim RB, Lonnerdal B, Yang M, Uematsu S, Hutson J, Watson-MacDonell J, Ito S: Induction of cytochrome P450 1A by cow milk-based formula: a comparative study between human milk and formula. Br J Pharmacol. 2005 Sep;146(2):296-305. [15997229 ]
  4. Sipes NS, Martin MT, Kothiya P, Reif DM, Judson RS, Richard AM, Houck KA, Dix DJ, Kavlock RJ, Knudsen TB: Profiling 976 ToxCast chemicals across 331 enzymatic and receptor signaling assays. Chem Res Toxicol. 2013 Jun 17;26(6):878-95. doi: 10.1021/tx400021f. Epub 2013 May 16. [23611293 ]
  5. ATSDR - Agency for Toxic Substances and Disease Registry (1995). Toxicological profile for PAHs. U.S. Public Health Service in collaboration with U.S. Environmental Protection Agency (EPA). [Link]
  6. Wikipedia. Benzopyrene. Last Updated 22 January 2009. [Link]
Target Details
2. Androgen receptor
General Function:
Zinc ion binding
Specific Function:
Steroid hormone receptors are ligand-activated transcription factors that regulate eukaryotic gene expression and affect cellular proliferation and differentiation in target tissues. Transcription factor activity is modulated by bound coactivator and corepressor proteins. Transcription activation is down-regulated by NR0B2. Activated, but not phosphorylated, by HIPK3 and ZIPK/DAPK3.
Gene Name:
AR
Uniprot ID:
P10275
Molecular Weight:
98987.9 Da
Binding/Activity Constants
TypeValueAssay TypeAssay Source
AC501.53 uMTox21_AR_LUC_MDAKB2_AgonistTox21/NCGC
References
  1. Vinggaard AM, Hnida C, Larsen JC: Environmental polycyclic aromatic hydrocarbons affect androgen receptor activation in vitro. Toxicology. 2000 Apr 14;145(2-3):173-83. [10771140 ]
  2. Sipes NS, Martin MT, Kothiya P, Reif DM, Judson RS, Richard AM, Houck KA, Dix DJ, Kavlock RJ, Knudsen TB: Profiling 976 ToxCast chemicals across 331 enzymatic and receptor signaling assays. Chem Res Toxicol. 2013 Jun 17;26(6):878-95. doi: 10.1021/tx400021f. Epub 2013 May 16. [23611293 ]
3. DNA
General Function:
Used for biological information storage.
Specific Function:
DNA contains the instructions needed for an organism to develop, survive and reproduce.
Molecular Weight:
2.15 x 1012 Da
References
  1. Uno S, Dragin N, Miller ML, Dalton TP, Gonzalez FJ, Nebert DW: Basal and inducible CYP1 mRNA quantitation and protein localization throughout the mouse gastrointestinal tract. Free Radic Biol Med. 2008 Feb 15;44(4):570-83. Epub 2007 Nov 12. [17997381 ]
  2. Padros J, Pelletier E: In vivo formation of (+)-anti-benzo[a]pyrene diol-epoxide-plasma albumin adducts in fish. Mar Environ Res. 2000 Jul-Dec;50(1-5):347-51. [11460716 ]
  3. ATSDR - Agency for Toxic Substances and Disease Registry (1995). Toxicological profile for PAHs. U.S. Public Health Service in collaboration with U.S. Environmental Protection Agency (EPA). [Link]
  4. Wikipedia. Benzopyrene. Last Updated 22 January 2009. [Link]
Target Details
4. Glycine N-methyltransferase
General Function:
Glycine n-methyltransferase activity
Specific Function:
Catalyzes the methylation of glycine by using S-adenosylmethionine (AdoMet) to form N-methylglycine (sarcosine) with the concomitant production of S-adenosylhomocysteine (AdoHcy). Possible crucial role in the regulation of tissue concentration of AdoMet and of metabolism of methionine.
Gene Name:
GNMT
Uniprot ID:
Q14749
Molecular Weight:
32742.0 Da
References
  1. Uno S, Dragin N, Miller ML, Dalton TP, Gonzalez FJ, Nebert DW: Basal and inducible CYP1 mRNA quantitation and protein localization throughout the mouse gastrointestinal tract. Free Radic Biol Med. 2008 Feb 15;44(4):570-83. Epub 2007 Nov 12. [17997381 ]
  2. Padros J, Pelletier E: In vivo formation of (+)-anti-benzo[a]pyrene diol-epoxide-plasma albumin adducts in fish. Mar Environ Res. 2000 Jul-Dec;50(1-5):347-51. [11460716 ]
  3. ATSDR - Agency for Toxic Substances and Disease Registry (1995). Toxicological profile for PAHs. U.S. Public Health Service in collaboration with U.S. Environmental Protection Agency (EPA). [Link]
  4. Wikipedia. Benzopyrene. Last Updated 22 January 2009. [Link]
Target Details
5. Nuclear receptor ROR-gamma
General Function:
Zinc ion binding
Specific Function:
Nuclear receptor that binds DNA as a monomer to ROR response elements (RORE) containing a single core motif half-site 5'-AGGTCA-3' preceded by a short A-T-rich sequence. Key regulator of cellular differentiation, immunity, peripheral circadian rhythm as well as lipid, steroid, xenobiotics and glucose metabolism. Considered to have intrinsic transcriptional activity, have some natural ligands like oxysterols that act as agonists (25-hydroxycholesterol) or inverse agonists (7-oxygenated sterols), enhancing or repressing the transcriptional activity, respectively. Recruits distinct combinations of cofactors to target gene regulatory regions to modulate their transcriptional expression, depending on the tissue, time and promoter contexts. Regulates the circadian expression of clock genes such as CRY1, ARNTL/BMAL1 and NR1D1 in peripheral tissues and in a tissue-selective manner. Competes with NR1D1 for binding to their shared DNA response element on some clock genes such as ARNTL/BMAL1, CRY1 and NR1D1 itself, resulting in NR1D1-mediated repression or RORC-mediated activation of the expression, leading to the circadian pattern of clock genes expression. Therefore influences the period length and stability of the clock. Involved in the regulation of the rhythmic expression of genes involved in glucose and lipid metabolism, including PLIN2 and AVPR1A. Negative regulator of adipocyte differentiation through the regulation of early phase genes expression, such as MMP3. Controls adipogenesis as well as adipocyte size and modulates insulin sensitivity in obesity. In liver, has specific and redundant functions with RORA as positive or negative modulator of expression of genes encoding phase I and Phase II proteins involved in the metabolism of lipids, steroids and xenobiotics, such as SULT1E1. Also plays also a role in the regulation of hepatocyte glucose metabolism through the regulation of G6PC and PCK1. Regulates the rhythmic expression of PROX1 and promotes its nuclear localization (By similarity). Plays an indispensable role in the induction of IFN-gamma dependent anti-mycobacterial systemic immunity (PubMed:26160376).Isoform 2: Essential for thymopoiesis and the development of several secondary lymphoid tissues, including lymph nodes and Peyer's patches. Required for the generation of LTi (lymphoid tissue inducer) cells. Regulates thymocyte survival through DNA-binding on ROREs of target gene promoter regions and recruitment of coactivaros via the AF-2. Also plays a key role, downstream of IL6 and TGFB and synergistically with RORA, for lineage specification of uncommitted CD4(+) T-helper (T(H)) cells into T(H)17 cells, antagonizing the T(H)1 program. Probably regulates IL17 and IL17F expression on T(H) by binding to the essential enhancer conserved non-coding sequence 2 (CNS2) in the IL17-IL17F locus. May also play a role in the pre-TCR activation cascade leading to the maturation of alpha/beta T-cells and may participate in the regulation of DNA accessibility in the TCR-J(alpha) locus.
Gene Name:
RORC
Uniprot ID:
P51449
Molecular Weight:
58194.845 Da
Binding/Activity Constants
TypeValueAssay TypeAssay Source
AC500.40 uMATG_RORg_TRANSAttagene
References
  1. Sipes NS, Martin MT, Kothiya P, Reif DM, Judson RS, Richard AM, Houck KA, Dix DJ, Kavlock RJ, Knudsen TB: Profiling 976 ToxCast chemicals across 331 enzymatic and receptor signaling assays. Chem Res Toxicol. 2013 Jun 17;26(6):878-95. doi: 10.1021/tx400021f. Epub 2013 May 16. [23611293 ]
Target Details
6. ATPase family AAA domain-containing protein 5
General Function:
Atp binding
Specific Function:
Involved in DNA damage response. Involved in a RAD9A-related damage checkpoint, a pathway that is important in determining whether DNA damage is compatible with cell survival or whether it requires cell elimination by apoptosis. Modulates the RAD9A interaction with BCL2 and thereby induces DNA damages-induced apoptosis.
Gene Name:
ATAD5
Uniprot ID:
Q96QE3
Molecular Weight:
207568.185 Da
Binding/Activity Constants
TypeValueAssay TypeAssay Source
AC500.77 uMTox21_ELG1_LUC_AgonistTox21/NCGC
References
  1. Sipes NS, Martin MT, Kothiya P, Reif DM, Judson RS, Richard AM, Houck KA, Dix DJ, Kavlock RJ, Knudsen TB: Profiling 976 ToxCast chemicals across 331 enzymatic and receptor signaling assays. Chem Res Toxicol. 2013 Jun 17;26(6):878-95. doi: 10.1021/tx400021f. Epub 2013 May 16. [23611293 ]
Target Details
7. Estrogen receptor
General Function:
Zinc ion binding
Specific Function:
Nuclear hormone receptor. The steroid hormones and their receptors are involved in the regulation of eukaryotic gene expression and affect cellular proliferation and differentiation in target tissues. Ligand-dependent nuclear transactivation involves either direct homodimer binding to a palindromic estrogen response element (ERE) sequence or association with other DNA-binding transcription factors, such as AP-1/c-Jun, c-Fos, ATF-2, Sp1 and Sp3, to mediate ERE-independent signaling. Ligand binding induces a conformational change allowing subsequent or combinatorial association with multiprotein coactivator complexes through LXXLL motifs of their respective components. Mutual transrepression occurs between the estrogen receptor (ER) and NF-kappa-B in a cell-type specific manner. Decreases NF-kappa-B DNA-binding activity and inhibits NF-kappa-B-mediated transcription from the IL6 promoter and displace RELA/p65 and associated coregulators from the promoter. Recruited to the NF-kappa-B response element of the CCL2 and IL8 promoters and can displace CREBBP. Present with NF-kappa-B components RELA/p65 and NFKB1/p50 on ERE sequences. Can also act synergistically with NF-kappa-B to activate transcription involving respective recruitment adjacent response elements; the function involves CREBBP. Can activate the transcriptional activity of TFF1. Also mediates membrane-initiated estrogen signaling involving various kinase cascades. Isoform 3 is involved in activation of NOS3 and endothelial nitric oxide production. Isoforms lacking one or several functional domains are thought to modulate transcriptional activity by competitive ligand or DNA binding and/or heterodimerization with the full length receptor. Essential for MTA1-mediated transcriptional regulation of BRCA1 and BCAS3. Isoform 3 can bind to ERE and inhibit isoform 1.
Gene Name:
ESR1
Uniprot ID:
P03372
Molecular Weight:
66215.45 Da
Binding/Activity Constants
TypeValueAssay TypeAssay Source
AC509.67 uMTox21_ERa_BLA_Agonist_ratioTox21/NCGC
References
  1. Sipes NS, Martin MT, Kothiya P, Reif DM, Judson RS, Richard AM, Houck KA, Dix DJ, Kavlock RJ, Knudsen TB: Profiling 976 ToxCast chemicals across 331 enzymatic and receptor signaling assays. Chem Res Toxicol. 2013 Jun 17;26(6):878-95. doi: 10.1021/tx400021f. Epub 2013 May 16. [23611293 ]