Hot topic: (but in this case, stale beer) the long overdue primary pharmacological characterisation of BIA 10-2747

The unfortunate French clinical trial disaster in which the FAAH inhibitor BIA 10-2747 (ligand ID 9001)  left one participant dead and several others with serious neurological adverse events, occurred back in January 2016.  However, the primary publication that describes the properties of this lead compound from its Portuguese originators BIAL has only now appeared in September of 2018 (1).  It is more typical for pharmaceutical medicinal chemistry teams to report their initial in vitro optimisation of a clinical candidate well in advance of Phase 1 (i.e. we might have expected to see this paper circa 2017).  While much has been written about 10-2747 in the last two years, very little peer-reviewed data has appeared (see this slide set and blog post).  In this context, the only BIAL journal paper so far on this compound is a disappointment.  The SAR of the series is only reported as % inhibition determinations rather than the more standardised and usefully comparative IC50s (this means we would actually not curate interaction data from such a paper but we have added the reference to the ligand entry). In addition, they do not address experimentally the irreversibility topic over which there has been some confusion. We would also quibble with the use of  “potent” in the title since an independent report of the initial IC50 binding  (i.e. without pre-incubation for inactivation) was only 7.5 uM (2).

Comments by Chris Southan (@cdsouthan)

  1. Kiss et al  (2018). Discovery of a Potent, Long-Acting, and CNS-Active Inhibitor (BIA 10-2474) of Fatty Acid Amide Hydrolase.  ChemMedChem, [Epub ahead of print]. [PMID:30113139].
  2. van Esbroeck et al. (2017) Activity-based protein profiling reveals off-target proteins of the FAAH inhibitor BIA 10-2474 Science, 356(6342):1084-1087 (PMID: 28596366)


Posted in Hot Topics

Hot topic: Cryo-EM structure of the active, Gs-protein complexed, human CGRP receptor

In this multi-author, multi-centre publication [1] lead by Denise Wootten and Patrick Sexton from the Monash Institute of Pharmacological Sciences, there is reported a 3.3 Angstrom structure of one of the more unusual G protein-coupled receptors. The CGRP receptor is a target for the recently FDA-approved monoclonal antibody erenumab targetting migraine. The receptor is unusual because of its modulation by a trio of accessory proteins exemplified here by RAMP1, which influence both the pharmacological and signalling profiles of the GPCR. Recent structural approaches to studies of GPCR have moved into investigations where a G protein is included. The Liang paper has a Gs heterotrimer attached, and, in addition, has the natural ligand, CGRP bound to the receptor. The report on this six molecule complex thus allows a major advance into the interaction between a GPCR, its endogenous agonist, the requisite G protein AND a modulatory protein.

Comments by Steve Alexander (@mqzspa)

(1) Liang YL et al. (2018). Cryo-EM structure of the active, Gs-protein complexed, human CGRP receptor. Nature, doi: 10.1038/s41586-018-0535-y. [Epub ahead of print]. [PMID: 30175587]

Posted in Hot Topics

Hot Topic: β-Subunit of the voltage-gated Ca2+ channel Cav1.2 drives signaling to the nucleus via H-Ras

This paper [1] extends previous studies demonstrating a key role of voltage-gated L-type Ca2+ channels in the modulation of activity-dependent gene transcription. Earlier work in cultured neurons had already shown that L-type channel activity is required to activate gene expression through different signaling pathways, including the Ras/MAPK pathway [2-4]. This is confirmed in the present study (primarily in experiments with HEK-293 cells) but there are important differences in the way nuclear signaling gets activated. In contrast to previous models [2], it is shown that the Ras/MAPK pathway is turned on by a direct physical interaction of the L-type channel (only Cav1.2 was studied) with Ras through the channel’s beta-subunit. Moreover, this interaction requires binding of extracellular Ca2+ to the pore-forming alpha1-subunit but no Ca2+ influx through the channel. Also no binding of calmodulin to the channel is required. This strongly suggests a direct conformational coupling of Cav1.2 to Ras activation and adds to other evidence of conformational coupling of L-type Ca2+ channels [5-6]. However, further experiments are required to demonstrate that this mechanism also exists in neurons.

Comments by Jörg Striessnig, University of Innsbruck

(1) Servili E et al. (2018). β-Subunit of the voltage-gated Ca2+ channel Cav1.2 drives signaling to the nucleus via H-Ras. Proc Natl Acad Sci USA, 115(37):E8624-E8633. doi: 10.1073/pnas.1805380115. [PMID: 30150369]

(2) Dolmetsch RE et al. (2001). Signaling to the nucleus by an L-type calcium channel-calmodulin complex through the MAP kinase pathway. Science, 294(5541):333-9. [PMID: 11598293]

(3) Wu GY et al. (2018). Activity-dependent CREB phosphorylation: convergence of a fast, sensitive calmodulin kinase pathway and a slow, less sensitive mitogen-activated protein kinase pathway. Cold Spring Harbor Perspect Biol, 98(5):2808-13. [PMID: 11226322]

(4) Hagenston AM & Bading H (2018). Calcium signaling in synapse-to-nucleus communication. Mol Pharmacol, 3(11):a004564. doi: 10.1101/cshperspect.a004564. [Epub ahead of print]. [PMID: 30021858]

(5) Krey JF et al. (2013). Timothy syndrome is associated with activity-dependent dendritic retraction in rodent and human neurons. Nat Neurosci 16:201-9. [PMID: 23313911]

(6) Li B et al. (2016). Sequential ionic and conformational signaling by calcium channels drives neuronal gene expression. Science 351:863-7. [PMID: 26912895]

Posted in Hot Topics

Database release 2018.4

Our fourth database release of the year, 2018.4, is now available (n.b. the PubChem update statistics and link sets will be posted in a couple of weeks).   This update contains the following new features and content changes:

Content Updates





Catalytic Receptors:


Other Proteins:


Recently added immunology/inflammation targets with novel pharmacological modulators include:

  • Fc fragment of IgG receptor IIIa (FCGR3A)
  • RAS guanyl releasing protein 1 (RASGRP1)
  • transglutaminase 2 (TGM2)
  • sialic acid binding Ig like lectin 8 (SIGLEC8)
  • CD37
  • signal transducer and activator of transcription 3 (STAT3)
  • signal transducer and activator of transcription 6 (STAT6)

In response to publication of ‘Ion channelopathies of the immune system’ (Vaeth and Feske, 2018; PMID:29635109), we have updated the immune cell type and GtoImmuPdb curation for the ion channels and transporters that the article and the ‘Guide’ have in common.

Guide to Malaria PHARAMCOLOGY

The Antimalarial targets family and the Antimalarial ligands family have been updated, giving a total of 9 P. falciparum (3D7) targets and 41 ligands tagged as antimalarial in the database.

Peptide Curation

Over the summer a MSc student, Lin Yakai, worked on a project to investigate GtoPdb peptide ligand structures and develop ways of converting these into standardised specifications (SMILES, InChi, HELM etc.). Using SugarNSplice software (SnS) we have been able to convert some peptides to SMILES format and submit these to PubChem – creating new CIDs from our SID structures. At this stage, we have converted ~400 peptides and on this release have curated the SMILES of around 40 peptides back into GtoPdb.  One of these includes the venerable “Entothelin-1” (Ligand ID 989)  that now specifies not only peptide sequence but also points to the CID.  There is a preliminary slide set on this topic but we will publish a detailed blog post in due course.

Other Announcements

  • We have now broken the 10,000 barrier for ligand IDs on the development server. However, it will still be some time before our PubChem SIDs hit this number since there have been a number of internal deprecations of superseded entries.
  • Ligand 10083 represents a new precedent in being curated from ChemRxiv,  The Preprint Server for Chemistry (where we have two papers that were subsequently published by ACS Omega). This gives us the advantage of being able to pick up key bioactive chemistry from open manuscripts many months before the papers are accepted and indexed in PubMed (using a DOI to enter the reference in our system).  This case was a cell-penetrant KDM5B covalent inhibitor with therapeutic relevance to immunopharmacology and cancer. The authors are from the Structural Genomics Consortium (SGC)
  • Nearly three years after the clinical trial fatality in January 2016  the primary pharmacological characterization paper for BIA-10-2747 has finally appeared (see Hot Topic report)


New website features

Extension to web-services

With the continuing development of the GtoImmuPdb we are pleased to announce that target and ligands of immunological relevance, as well as the new immunopharmacology data types can now be retrieved via our web services.

For example, targets tagged in the database as relevant to immunopharmacology can be retrieved form the following URL:

Lists if immuno processes and cell types can be returned for specific targets. Here an example retrieving cell types associated with CD86 (target ID 2735):

We have also introduced disease data to the web services, so summarised data for any disease in GtoPdb can be retrieved, here using Psoriasis (disease ID 801) as an example:


We have extended the file formats to include both csv and tsv formats on our downloads page.


We have extended our about page to include a few extra statistics on ligand counts with clinical use summaries and interactions.

Posted in Database updates, Guide to Immunopharmacology, Guide to Malaria Pharmacology

July 2018 News, Updates and Hot Topics

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July 2018

News, Updates and Hot Topics

Database release 2018.3:

Our third database release of the year, 2018.3, is now available. This update contains the following new features and content changes:

  • Updates across several target classes.
  • The existing Antimalarial targets family has been updated with 5 new P. falciparum (3D7) targets:
    • PfATP4 (Plasmodium falciparum ATPase4)
    • PfDHFR-TS (Plasmodium falciparum bifunctional dihydrofolate reductase-thymidylate synthase)
    • PfDXR (Plasmodium falciparum 1-deoxy-D-xylulose 5-phosphate reductoisomerase)
    • PfeEF2 (Plasmodium falciparum elongation factor 2)
    • PfPI4K (Plasmodium falciparum phosphatidylinositol 4-kinase)
  • A new Antimalarial ligands family has been created and contains 30 ligands all tagged as an antimalarial in the database. Of these 30, 20 are new ligands curated for this release.
  • GtoImmuPdb now public

The IUPHAR Guide to IMMUNOPHARMACOLOGY is now at its first public release and is no longer considered a beta version. We will continue to develop the portal and specific immuno interfaces as well as continuing curation towards its official launch in October 2018 (see blog post here

Recent Papers from the Team

We are pleased to point to three.  Two were close in succession, both initially as pre-prints in ChemRxiv and later accepted in ACS Omega.  Both are Open Acess and will be full-text indexed in  PubMed Central and European PubMed Central in due course.

“SynPharm: A Guide to PHARMACOLOGY Database Tool for Designing Drug Control into Engineered Proteins” Ireland

“Challenges of Connecting Chemistry to Pharmacology: Perspectives from Curating the IUPHAR/BPS Guide to PHARMACOLOGY”  Southan et. al. DOI/10.1021/acsomega.8b00884.

The third has been on the Current Protocols in Bioinformatics website for some months but was only just recently indexed in PubMed as “Accessing Expert-Curated Pharmacological Data in the IUPHAR/BPS Guide to PHARMACOLOGY”  Sharman et. al. PMID 30040201.

Hot Topics

The Guide to PHARMACOLOGY hot topics are new and significant pharmacology, drug discovery and key human genomics papers. These are often communicated to us through our expert subcommittee members. All hot topic papers are listed on the hot topics page on the website ( For a selection, we commission concise commentaries from our expert contacts and these are posted onto our blog (

Here we summarise the latest hot topic commentaries:

New pharmacological tools reiterate lack of direct connection between Angiotensin 1–7 and the MAS1 GPCR

Comments by Sadashiva S. Karnik ( and Kalyan Tirupula

A new type of deorphanization conundrum confronted in pairing the GPCR, MAS1 with the hormonal peptide angiotensin 1–7 (Ang1-7) was emphasised in recent IUPHAR reviews… Read more.

Structural details for coupling of the agonist-occupied µ opioid receptor (amongst others) to the Gi protein

Comments by Eamonn Kelly ( and Katy Sutcliffe

Every few years in the field of receptor pharmacology, a technological advance occurs that drives the field forward in terms of insight and understanding. Over the past couple of years, the cryo-EM technique (the development of which won the 2017 Nobel Prize in Chemistry for Dubochet, Frank, and Henderson) for resolving protein structures… Read more.

Systems Medicine, Disease Maps and the future of Systems Biology

Comments by Steven Watterson (@systemsbiology), University of Ulster

What will Systems Biology look like in the future? Up to now, it has focussed on the development of standards, software tools and databases that enabled us to study the dynamics of physiological function mechanistically. Read more.

Structure of the adenosine-bound human adenosine A1 receptor–Gi complex

Comments by Steve Alexander (@mqzspa)

The A1 adenosine receptor is, for most people, a molecular target they can become conscious of when they block it, which happens frequently. Rapid consumption of higher doses of caffeine, in products like Italian espresso or Turkish coffee, provokes a … Read more.

Commentary on the distinction between Cannabis and cannabinoids

Commentary by Steve Alexander (@mqzspa) & Anthony Davenport

The Cannabis plant is a natural product from which more than 100 apparently unique metabolites (cannabinoids) have been identified. Many of these have been found in human plasma following consumption of Cannabis preparations. Read more.

(Update): From double to triple whammy for BACE1 inhibitors

Comments by Chris Southan (@cdsouthan)

19 June 2018 update. Announced only about a week after the events described below,  yet a third clinical candidate, lanabecestat  (AZD-3293, LY3314814) has also bitten the dust (4).  The two PhIII trials were stopped because they were deemed unlikely to meet their primary endpoints. Read more.

Cryo-EM structure of the adenosine A2A receptor coupled to an engineered heterotrimeric G protein

Comments by Steve Alexander (@mqzspa)

The A2A adenosine receptor is densely expressed in dopamine-rich areas of the brain and in the vasculature. It is the target of an adjunct medication for Parkinson’s Disease, istradefylline in Japan, an A2A receptor antagonist. Read more.

Conformational plasticity in the selectivity filter of the TRPV2 ion channel

Comments by Steve Alexander (@mqzspa)

The TRPV2 ion channel is the less well-characterised relative of the TRPV1 or vanilloid receptor that is activated by capsaicin. TRPV2 channels have many similarities to the TRPV1 channels, in that they are homotetrameric and respond to some of the same ligands (natural products such as cannabinoids) as well as being triggered at elevated temperatures. Read more.

3D structure of the P2X3 receptor bound to a negative allosteric modifier, identifies a binding site that is a target for development of novel therapeutic agents

Comments by Dr. Charles Kennedy, University of Strathclyde

Negative allosteric modulators (NAMs) are of great interest in drug development because they offer improved scope for the production of receptor antagonists with enhanced subtype-selectivity. Indeed, many NAMs are already on the market or undergoing clinical trials. NAMs act byRead more.

3D structures of the closed acid-sensing ion channel (ASIC) shed light on the activation mechanism of these neuronal ion channels

Comments by Stephen Kellenberger, Université de Lausanne, Switzerland

ASICs are potential drug targets of interest. Their activation mechanism has however remained elusive. ASICs are neuronal, proton-gated, sodium-permeable channels that are expressed in the central and peripheral nervous system of vertebrates. Read more.

Engineered mini G proteins provide a useful tool for studying the activation of GPCRs in living cells

Comments by Shane C. Wright and Gunnar Schulte, Karolinska Institute

In order to stabilize the GPCR-G protein complex, an agonist must be bound to the receptor and the alpha subunit of the heterotrimer must be in a nucleotide-free state. Read more.

Unexplored therapeutic opportunities in the human genome

Comments by Chris Southan, IUPHAR/BPS Guide to PHARMACOLOGY, @cdsouthan

Contemporary drug discovery is dominated by two related  themes. The first of these is target validation upon which the sustainability of pharmaceutical R&D (in both the commercial and academic sectors) crucially depends. Read more.


Ireland SM, Southan C, Dominguez-Monedero, Harding SD, Sharman JL, Davies JD. (2018). SynPharm: A Guide to PHARMACOLOGY Database Tool for Designing Drug Control into Engineered Proteins. ACS Omega, 3 (7), pp 7993–8002, doi: 10.1021/acsomega.8b00659.

Southan C, Sharman JL, Faccenda E, Pawson AJ, Harding SD, Davies JA. (2018). Challenges of Connecting Chemistry to Pharmacology: Perspectives from Curating the IUPHAR/BPS Guide to PHARMACOLOGY. ACS Omega, 3 (7), pp 8408–8420, doi: 10.1021/acsomega.8b00884.

Davenport AP, Kuc RE, Southan C, Maguire JJ. (2018). New drugs and emerging therapeutic targets in the endothelin signaling pathway and prospects for personalized precision medicine. Physiol. Res., (Suppl. 1): S37-S54, doi: 10.1021/acsomega.8b00659. [PMID:29947527]



Caraci F, Calabrese F, Molteni R, Bartova L, Dold M, Leggio GM, Fabbri C, Mendlewicz J, Racagni G, Kasper S, Riva MA, Drago F. (2018) International Union of Basic and Clinical Pharmacology CIV: The Neurobiology of Treatment-resistant Depression: From Antidepressant Classifications to Novel Pharmacological Targets. Pharmacol Rev. 70: 475-504. [PMID:29884653]

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Posted in Hot Topics

Hot topic: Direct activation of neuronal KV7 channels by GABA and gabapentin – a novel mechanism for reducing neuronal excitability

The potassium channels KV7.2-KV7.5 (KCNQ2-5; GtoPdb target IDs 561-564) regulate neuronal excitability in the mammalian nervous system. The best characterised neuronal KV7 channels give rise to the M current (1) and are mediated predominantly by hetero-tetramers of KV7.2 and KV7.3 subunits (2). Established anticonvulsant agents such as retigabine are known to dampen neuronal excitability by activating neuronal KV7 channels. A tryptophan in the S5 transmembrane region of neuronal KV7 channels is essential for retigabine sensitivity with KV7.3 channels particularly sensitive. Importantly, this residue is not present in the cardiac KV7.1 (KCNQ1) channel, reducing the potential for cardiac side effects.

Now, a pair of studies (3, 4) has shown that this same region of the channel also contributes to a high affinity binding site for GABA and related metabolites (3). GABA activates channels comprised of KV7.3 and KV7.5, including heteromeric KV7.2/7.3 channels, with high potency but low efficacy. GABA does not, however, activate KV7.2 or KV7.4 homomeric channels or cardiac KV7.1 channels. The synthetic anticonvulsant and antinociceptive agent gabapentin activates the same KV7 subunits, although pregabalin does not, despite the overlapping therapeutic efficacy of these two compounds (4).

These results are of considerable pharmacological interest. They suggest a novel mechanism for GABA in regulating neuronal excitability through activation of KV7 channels. They indicate that both GABA and gabapentin will interfere with the action of therapeutically useful activators of KV7 channels such as retigabine. However, perhaps of most value given the relative difficulty in identifying potassium channel openers compared to blockers (5), this work identifies a new chemical class of potential therapeutic activators of neuronal KV7 channels that target an identified region of these channels.

Comments by Emma L. Veale (@Ve11Emma) and Alistair Mathie (@AlistairMathie)

(1) Brown, D.A. & Adams P.R. (1980). Muscarinic suppression of a novel voltage-sensitive K+ current in a vertebrate neurone. Nature, 283. 673-676. [PMID: 6965523].

(2) Wang H.S. et al. (1998). KCNQ2 and KCNQ3 potassium channel subunits: molecular correlates of the M-channel. Science, 282. 1890-1893. [PMID: 9836639].

(3) Manville R.W. et al. (2018). Direct neurotransmitter activation of voltage-gated potassium channels. Nature Commun., 9(1). 1847. [PMID: 29748663].

(4) Manville R.W. & Abbott G. (2018). Gabapentin is a potent activator of KCNQ3 and KCNQ5 potassium channels. Mol. Pharmacol., doi: 10.1124/mol.118.112953. [PMID: 30021858].

(5) Liin, S.I. et al. (2018). Biaryl sulfonamide motifs up- or down-regulate ion channel activity by activating voltage sensors. J. Gen. Physiol., doi: 10.1085/jgp.201711942. [PMID: 30002162].

Posted in Hot Topics

Hot topic: New pharmacological tools reiterate lack of direct connection between Angiotensin 1–7 and the MAS1 GPCR

A new type of deorphanization conundrum confronted in pairing the GPCR, MAS1 with the hormonal peptide angiotensin 1–7 (Ang1-7) was emphasised in recent IUPHAR reviews (1, 2). More evidence for disconnection between Ang1-7 and MAS1 is presented in the recent paper by Gaidarov et al. (3). Ang1-7 is produced by ACE2 or neutral endopeptidase by cleavage of a single amino acid, phenylalanine 8, from angiotensin II (AngII), the major renin angiotensin system hormone. MAS1 was described as the primary receptor for Ang1-7 in regulating diverse biological activities, including vasodilatory, cardio-protective, antithrombotic, antidiuretic and antifibrotic effects (4). These activities are lost in tissues of MAS1-deficient animals, producing striking phenotypes observed in the cardiovascular, renovascular, nervous and reproductive systems. Vast physiological responses to Ang1-7 studied in MAS1-deficient animals serve as the most compelling argument in favor of Ang1-7 pairing with MAS1. However, support for a direct interaction of Ang1-7 with MAS1 lack demonstration of classical G protein signaling and desensitization response to Ang1-7, as well as a lack consensus on confirmatory molecular pharmacological analyses (1, 2).

MAS1-selective small molecule agonists and antagonists from Arena Pharmaceuticals have aided mechanistic study of signaling dynamics in recombinant MAS1 expressing cells. Gaidarov et al. systematically tested efficacy of MAS1-selective non-peptide agonists and antagonists in GPCR signaling and also in signaling-pathway independent assay platforms [3]. Arena Pharmaceutical’s non-peptide ligands modulated G protein-dependent and independent pathways through MAS1, including Gq and Gi pathways, 35S-GTPɣS binding, β-arrestin recruitment, Erk1/2 and Akt phosphorylation, arachidonic acid release, and receptor internalization. Moreover, non-peptide agonists produced robust responses in dynamic mass redistribution (DMR) assays that provide a pathway-agnostic cellular response. The Ang1-7 peptide obtained from multiple sources was inert. In the cell-free assay for G protein coupled MAS1, 35S-GTPɣS binding was undetected in the presence of Ang1–7 suggesting lack of direct interaction with MAS1.

To reject the in vivo analysis based MAS1 pairing with Ang1-7 would still be premature based on the conclusions of Gaidarov et al. (and similar papers cited in ref. #2). MAS1 pairing with Ang1-7 should be considered in the context of type 1 and type 2 errors originally described by Neyman and Pearson (5) and recently revisited (6). Type 1 errors are experiments causing rejection of a null hypothesis which may be true. Type 2 errors are experiments insufficient to reject a flawed null hypothesis. Experiments need to be designed to test the validity of MAS1 functions modulated in vivo by Arena Pharmaceutical ligands rather than simply failing to find pairing with Ang1-7. Involvement of additional GPCRs as “Ang1-7 receptors” or signalosome mechanisms that can link Ang1-7 with MAS1 deserve consideration (7).

Comments by Sadashiva S. Karnik ( and Kalyan Tirupula


  1. Karnik SS, Singh KD, Tirupula K, Unal H. (2017) Significance of angiotensin 1-7 coupling with MAS1 receptor and other GPCRs to the renin-angiotensin system: IUPHAR Review 22. Br J Pharmacol. 174: 737-753. doi: 10.1111/bph.13742. Review. PMID: 28194766
  2. Karnik SS, Unal H, Kemp JR, Tirupula KC, Eguchi S et al. (2015) International Union of Basic and Clinical Pharmacology. XCIX. Angiotensin Receptors: Interpreters of Pathophysiological Angiotensinergic Stimuli [corrected]. Pharmacol Rev 67: 754-819. PMID: 26315714
  3. Gaidarov I, Adams J, Frazer J, Anthony T, Chen X et al. (2018) Angiotensin (1-7) does not interact directly with MAS1, but can potently antagonize signaling from the AT1 receptor. Cell Signal 50: 9-24. PMID: 29928987
  4. Bader M, Alenina N, Andrade-Navarro MA, Santos RA (2014). MAS and its related G protein-coupled receptors, Mrgprs. Pharmacol Rev. 66: 1080–1105. PMID: 25244929
  5. Neyman, J. and Pearson, E.S. (1928). On the use and interpretation of certain test criteria for the purposes of statistical inference. Part I and Part II. Biometrika 20A, 175–240.
  6. Lew MJ (2006). Principles: when there should be no difference–how to fail to reject the null hypothesis. Trends Pharmacol Sci. 27:274-278. PMID: 16595154
  7. Tirupula KC, Zhang D, Osbourne A, Chatterjee A, Desnoyer R, Willard B et al. (2015). MAS C-terminal tail interacting proteins identified by mass spectrometry-based proteomic approach. PLoS One 10: e0140872. PMID: 26484771
Posted in Hot Topics