Discovery and Characterization of a Bicyclic Peptide (Bicycle) Binder to Thymic Stromal Lymphopoietin

Thymic stromal lymphopoietin (TSLP) is an epithelial-derived pro-inflammatory cytokine involved in the development of asthma and other atopic diseases. We used Bicycle Therapeutics' proprietary phage display platform to identify bicyclic peptides (Bicycles) with high affinity for TSLP, a target that is difficult to drug with conventional small molecules due to the extended protein-protein interactions it forms with both receptors. The hit series was shown to bind to TSLP in a hotspot, that is also used by IL-7Rα. Guided by the first X-ray crystal structure of a small peptide binding to TSLP and the identification of key metabolites, we were able to improve the proteolytic stability of this series in lung S9 fractions without sacrificing binding affinity. This resulted in the potent Bicycle 46 with nanomolar affinity to TSLP (KD = 13 nM), low plasma clearance of 6.4 mL/min/kg, and an effective half-life of 46 min after intravenous dosing to rats.

Observation of Directed Flow of Hypernuclei _{Λ}^{3}H and _{Λ}^{4}H in sqrt[s_{NN}]=3 GeV Au+Au Collisions at RHIC

We report here the first observation of directed flow (v_{1}) of the hypernuclei _{Λ}^{3}H and _{Λ}^{4}H in mid-central Au+Au collisions at sqrt[s_{NN}]=3  GeV at RHIC. These data are taken as part of the beam energy scan program carried out by the STAR experiment. From 165×10^{6} events in 5%-40% centrality, about 8400 _{Λ}^{3}H and 5200 _{Λ}^{4}H candidates are reconstructed through two- and three-body decay channels. We observe that these hypernuclei exhibit significant directed flow. Comparing to that of light nuclei, it is found that the midrapidity v_{1} slopes of _{Λ}^{3}H and _{Λ}^{4}H follow baryon number scaling, implying that the coalescence is the dominant mechanism for these hypernuclei production in the 3 GeV Au+Au collisions.

Exploring the benefits of nature-based interventions in socio-economically deprived communities: a narrative review of the evidence to date

AIM

Socio-economic deprivation encompasses the relative disadvantage experienced by individuals or communities in relation to financial, material or social resources. Nature-based interventions (NBIs) are a public health approach that promote sustainable, healthy communities through engagement with nature and show potential to address inequalities experienced by socio-economically deprived communities. This narrative review aims to identify and evaluate the benefits of NBIs in socio-economically deprived communities.

METHOD

A systematic literature search of six electronic publication databases (APA PsycInfo, CENTRAL, CDSR, CINAHL, Medline and Web of Science) was conducted on 5 February 2021 and repeated on 30 August 2022. In total, 3852 records were identified and 18 experimental studies (published between 2015 and 2022) were included in this review.

RESULTS

Interventions including therapeutic horticulture, care farming, green exercise and wilderness arts and craft were evaluated in the literature. Key benefits were observed for cost savings, diet diversity, food security, anthropometric outcomes, mental health outcomes, nature visits, physical activity and physical health. Age, gender, ethnicity, level of engagement and perception of environment safety influenced the effectiveness of the interventions.

CONCLUSION

Results demonstrate there are clear benefits of NBIs on economic, environmental, health and social outcomes. Further research including qualitative analyses, more stringent experimental designs and use of standardised outcome measures is recommended.

Measurement of Sequential ϒ Suppression in Au+Au Collisions at sqrt[s_{NN}]=200 GeV with the STAR Experiment

We report on measurements of sequential ϒ suppression in Au+Au collisions at sqrt[s_{NN}]=200  GeV with the STAR detector at the Relativistic Heavy Ion Collider (RHIC) through both the dielectron and dimuon decay channels. In the 0%-60% centrality class, the nuclear modification factors (R_{AA}), which quantify the level of yield suppression in heavy-ion collisions compared to p+p collisions, for ϒ(1S) and ϒ(2S) are 0.40±0.03(stat)±0.03(sys)±0.09(norm) and 0.26±0.08(stat)±0.02(sys)±0.06(norm), respectively, while the upper limit of the ϒ(3S) R_{AA} is 0.17 at a 95% confidence level. This provides experimental evidence that the ϒ(3S) is significantly more suppressed than the ϒ(1S) at RHIC. The level of suppression for ϒ(1S) is comparable to that observed at the much higher collision energy at the Large Hadron Collider. These results point to the creation of a medium at RHIC whose temperature is sufficiently high to strongly suppress excited ϒ states.

Beam Energy Dependence of Fifth- and Sixth-Order Net-Proton Number Fluctuations in Au+Au Collisions at RHIC

We report the beam energy and collision centrality dependence of fifth and sixth order cumulants (C_{5}, C_{6}) and factorial cumulants (κ_{5}, κ_{6}) of net-proton and proton number distributions, from center-of-mass energy (sqrt[s_{NN}]) 3 GeV to 200 GeV Au+Au collisions at RHIC. Cumulant ratios of net-proton (taken as proxy for net-baryon) distributions generally follow the hierarchy expected from QCD thermodynamics, except for the case of collisions at 3 GeV. The measured values of C_{6}/C_{2} for 0%-40% centrality collisions show progressively negative trend with decreasing energy, while it is positive for the lowest energy studied. These observed negative signs are consistent with QCD calculations (for baryon chemical potential, μ_{B}≤110  MeV) which contains the crossover transition range. In addition, for energies above 7.7 GeV, the measured proton κ_{n}, within uncertainties, does not support the two-component (Poisson+binomial) shape of proton number distributions that would be expected from a first-order phase transition. Taken in combination, the hyperorder proton number fluctuations suggest that the structure of QCD matter at high baryon density, μ_{B}∼750  MeV at sqrt[s_{NN}]=3  GeV is starkly different from those at vanishing μ_{B}∼24  MeV at sqrt[s_{NN}]=200  GeV and higher collision energies.

A realist approach to understanding alliancing within Local Government public health and social care service provision

BACKGROUND

Within the current context of continued austerity and post-pandemic recovery, it remains important that Local Government services address the increasing needs of residents as cost-effectively as possible. Alliancing, whereby services work collaboratively focusing on the 'whole-system', has gained popularity as a tool with the potential to support collaborative whole systems approaches. This synthesis aims to identify how alliancing can be successfully operationalised in the commissioning of public health, wider National Health Service (NHS) and social care-related services.

METHODS

A realist literature synthesis was undertaken in order to identify underlying generative mechanisms associated with alliancing, the contextual conditions surrounding the implementation and operationalisation of the alliancing approach mechanisms, and the outcomes produced as a result. An iterative approach was taken, using a recent systematic review of the effectiveness of Alliancing, online database searches, and grey literature searches.

RESULTS

Three mechanistic components were identified within the data as being core to the successful implementation of alliances in public health and social care-related services within Local Government: (i) Achieving a system-level approach; (ii) placing local populations at the heart of the system; and (iii) creating a cultural shift. Programme theories were postulated within these components.

CONCLUSIONS

The alliancing approach offers an opportunity to achieve system-level change with the potential to benefit local populations. The realist synthesis approach taken within this study has provided insights into the necessary contextual and mechanistic factors of the Alliancing approach, above and beyond effectiveness outcomes typically collected through more conventional evaluation methodologies.

Collision-System and Beam-Energy Dependence of Anisotropic Flow Fluctuations

Elliptic flow measurements from two-, four-, and six-particle correlations are used to investigate flow fluctuations in collisions of U+U at sqrt[s_{NN}]=193  GeV, Cu+Au at sqrt[s_{NN}]=200  GeV and Au+Au spanning the range sqrt[s_{NN}]=11.5-200  GeV. The measurements show a strong dependence of the flow fluctuations on collision centrality, a modest dependence on system size, and very little if any, dependence on particle species and beam energy. The results, when compared to similar LHC measurements, viscous hydrodynamic calculations, and trento model eccentricities, indicate that initial-state-driven fluctuations predominate the flow fluctuations generated in the collisions studied.

BT8009; A Nectin-4 Targeting Bicycle Toxin Conjugate for Treatment of Solid Tumors

Multiple tumor types overexpress Nectin-4 and the antibody-drug conjugate (ADC), enfortumab vedotin (EV) shows striking efficacy in clinical trials for metastatic urothelial cancer, which expresses high levels of Nectin-4, validating Nectin-4 as a clinical target for toxin delivery in this indication. Despite excellent data in urothelial cancer, little efficacy data are reported for EV in other Nectin-4 expressing tumors and EV therapy can produce significant toxicities in many patients, frequently leading to discontinuation of treatment. Thus, additional approaches to this target with the potential to extend utility and reduce toxicity are warranted. We describe the preclinical development of BT8009, a "Bicycle Toxin Conjugate" (BTC) consisting of a Nectin-4-binding bicyclic peptide, a cleavable linker system and the cell penetrant toxin mono-methylauristatin E (MMAE). BT8009 shows significant antitumor activity in preclinical tumor models, across a variety of cancer indications and is well tolerated in preclinical safety studies. In several models, it shows superior or equivalent antitumor activity to an EV analog. As a small hydrophilic peptide-based drug BT8009 rapidly diffuses from the systemic circulation, through tissues to penetrate the tumor and target tumor cells. It is renally eliminated from the circulation, with a half-life of 1-2 hours in rat and non-human primate. These physical and PK characteristics differentiate BT8009 from ADCs and may provide benefit in terms of tumor penetration and reduced systemic exposure. BT8009 is currently in a Phase 1/2 multicenter clinical trial across the US, Canada, and Europe, enrolling patients with advanced solid tumors associated with Nectin-4 expression.

301 BENEFITS OF ENVIRONMENTAL MUSIC THERAPY IN AN ACUTE HOSPITAL

Background

Environmental Music Therapy (EMT) uses live music played by a music therapist to enhance the surrounding environment and is increasingly used in clinical settings. Studies show that EMT may reduce anxiety, enhance wellbeing, promote better communication between patients and staff, and reduce patient perception of waiting times in hospital. We aimed to explore the benefit of EMT for older adults in a geriatric outpatient setting and on rehabilitation wards.

Methods

Harp music was played by a music therapist in the vicinity of ambulatory clinics and on rehabilitation wards for 4 hours per week (over a 2-day period) for 20 weeks. Music exposure on any given day was to an estimated 50 outpatients, as well as 50 people passing the vicinity or to about 30 patients on the rehabilitation ward. Music was selected and played in a dynamic process, responding to verbal and non-verbal reactions of patients, family, and staff. Voluntary responses were recorded and collated.

Results

There were 36 recorded responses and all reflected positively on EMT. Patients cited that the music created a welcoming space and stimulated interaction and conversation. Several patients waiting for their clinic appointment noted that it distracted from fearful expectation and was a source of comfort. Some commented that they felt more relaxed and that it reduced stress. On rehabilitation wards, patients found familiar music to be calming with nurses citing that it stimulated social interaction between patients, family and staff. Responses to EMT gave insights that resulted in patient referrals for music therapy.

Conclusion

Environmental music played by a music therapist was found to modify patient hospital experiences. In particular, it appeared to reduce self-perceived stress and stimulate positive social interaction and conversation. This supports the use of EMT to advance the integration of the arts for wellbeing in an acute hospital.

Evidence for Nonlinear Gluon Effects in QCD and Their Mass Number Dependence at STAR

The STAR Collaboration reports measurements of back-to-back azimuthal correlations of di-π^{0}s produced at forward pseudorapidities (2.6<η<4.0) in p+p, p+Al, and p+Au collisions at a center-of-mass energy of 200 GeV. We observe a clear suppression of the correlated yields of back-to-back π^{0} pairs in p+Al and p+Au collisions compared to the p+p data. The observed suppression of back-to-back pairs as a function of transverse momentum suggests nonlinear gluon dynamics arising at high parton densities. The larger suppression found in p+Au relative to p+Al collisions exhibits a dependence of the saturation scale Q_{s}^{2} on the mass number A. A linear scaling of the suppression with A^{1/3} is observed with a slope of -0.09±0.01.

Abstract 4233: Generation of a Bicycle NK-TICA™, a novel NK cell engaging molecule designed to induce targeted tumor cytotoxicity

The tumor specific activation of natural killer (NK) cells is an area of active investigation in immune oncology, but to date has relied on complex biologic modalities (e.g., antibodies, fusion proteins, or cell therapies). NK cells are highly responsive immune cells that can detect and eliminate tumor cells and bridge innate to adaptive immune responses. Bicycles® are small (ca.1.5kDa), chemically synthetic, structurally constrained peptides discovered via phage display and optimized using structure-driven design and medicinal chemistry approaches. We have applied the Bicycle platform technology to identify Bicycles® that bind specifically to the key activating receptor, NKp46. When chemically coupled to tumor antigen binding Bicycles, this results in highly potent, antigen-dependent receptor activation and NK cell activation. We term this new class of fully synthetic molecules NK-TICAs and we will describe herein their discovery and evaluation.We demonstrate potent, selective binding of our Bicycles to receptor-expressing cells and the capability of the bifunctional molecule to induce NK cell function in vitro. With Bicycle’s novel NK-TICA™ compound, we demonstrate the engagement of NK cells, the specific activation and function of NK cells, and enhanced tumor cytotoxicity in a tumor target- and dose-dependent manner.In conclusion, NK-TICAs drive NK cell-mediated tumor cell killing and cytokine production in vitro and as such have the potential to catalyze the development of durable anti-tumor immunity in tumor types not well served by current therapies. We hypothesize that utilization of Bicycle NK-TICA™ as a multifunctional immune cell engager will promote the modulation of NK cells, as well as the infiltration and anti-tumor activity of NK cells in solid tumors. The data presented here provide initial proof of concept for the application of our Bicycle technology to drive NK cell-mediated tumor immunity.

Citation Format: Fay J. Dufort, Christopher J. Leitheiser, Gemma Mudd, Julia Kristensson, Alexandra Rezvaya, Katie Gaynor, Sandra Uhlenbroich, Liudvikas Urbonas, Heather Scott, Liuhong Chen, Helen Harrison, Michael Skynner, Kevin McDonnell, Philip E. Brandish, Nicholas Keen. Generation of a Bicycle NK-TICA™, a novel NK cell engaging molecule designed to induce targeted tumor cytotoxicity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 4233.

Measurements of Proton High-Order Cumulants in sqrt[s_{NN}]=3 GeV Au+Au Collisions and Implications for the QCD Critical Point

We report cumulants of the proton multiplicity distribution from dedicated fixed-target Au+Au collisions at sqrt[s_{NN}]=3.0  GeV, measured by the STAR experiment in the kinematic acceptance of rapidity (y) and transverse momentum (p_{T}) within -0.5<y<0 and 0.4<p_{T}<2.0  GeV/c. In the most central 0%-5% collisions, a proton cumulant ratio is measured to be C_{4}/C_{2}=-0.85±0.09 (stat)±0.82 (syst), which is 2σ below the Poisson baseline with respect to both the statistical and systematic uncertainties. The hadronic transport UrQMD model reproduces our C_{4}/C_{2} in the measured acceptance. Compared to higher energy results and the transport model calculations, the suppression in C_{4}/C_{2} is consistent with fluctuations driven by baryon number conservation and indicates an energy regime dominated by hadronic interactions. These data imply that the QCD critical region, if created in heavy-ion collisions, could only exist at energies higher than 3 GeV.

Measurements of _{Λ}^{3}H and _{Λ}^{4}H Lifetimes and Yields in Au+Au Collisions in the High Baryon Density Region

We report precision measurements of hypernuclei _{Λ}^{3}H and _{Λ}^{4}H lifetimes obtained from Au+Au collisions at sqrt[s_{NN}]=3.0  GeV and 7.2 GeV collected by the STAR experiment at the Relativistic Heavy Ion Collider, and the first measurement of _{Λ}^{3}H and _{Λ}^{4}H midrapidity yields in Au+Au collisions at sqrt[s_{NN}]=3.0  GeV. _{Λ}^{3}H and _{Λ}^{4}H, being the two simplest bound states composed of hyperons and nucleons, are cornerstones in the field of hypernuclear physics. Their lifetimes are measured to be 221±15(stat)±19(syst)  ps for _{Λ}^{3}H and 218±6(stat)±13(syst)  ps for _{Λ}^{4}H. The p_{T}-integrated yields of _{Λ}^{3}H and _{Λ}^{4}H are presented in different centrality and rapidity intervals. It is observed that the shape of the rapidity distribution of _{Λ}^{4}H is different for 0%-10% and 10%-50% centrality collisions. Thermal model calculations, using the canonical ensemble for strangeness, describes the _{Λ}^{3}H yield well, while underestimating the _{Λ}^{4}H yield. Transport models, combining baryonic mean-field and coalescence (jam) or utilizing dynamical cluster formation via baryonic interactions (phqmd) for light nuclei and hypernuclei production, approximately describe the measured _{Λ}^{3}H and _{Λ}^{4}H yields. Our measurements provide means to precisely assess our understanding of the fundamental baryonic interactions with strange quarks, which can impact our understanding of more complicated systems involving hyperons, such as the interior of neutron stars or exotic hypernuclei.

Probing the Gluonic Structure of the Deuteron with J/ψ Photoproduction in d+Au Ultraperipheral Collisions

Understanding gluon density distributions and how they are modified in nuclei are among the most important goals in nuclear physics. In recent years, diffractive vector meson production measured in ultraperipheral collisions (UPCs) at heavy-ion colliders has provided a new tool for probing the gluon density. In this Letter, we report the first measurement of J/ψ photoproduction off the deuteron in UPCs at the center-of-mass energy sqrt[s_{NN}]=200  GeV in d+Au collisions. The differential cross section as a function of momentum transfer -t is measured. In addition, data with a neutron tagged in the deuteron-going zero-degree calorimeter is investigated for the first time, which is found to be consistent with the expectation of incoherent diffractive scattering at low momentum transfer. Theoretical predictions based on the color glass condensate saturation model and the leading twist approximation nuclear shadowing model are compared with the data quantitatively. A better agreement with the saturation model has been observed. With the current measurement, the results are found to be directly sensitive to the gluon density distribution of the deuteron and the deuteron breakup process, which provides insights into the nuclear gluonic structure.

Search for the Chiral Magnetic Effect via Charge-Dependent Azimuthal Correlations Relative to Spectator and Participant Planes in Au+Au Collisions at sqrt[s_{NN}]=200 GeV

The chiral magnetic effect (CME) refers to charge separation along a strong magnetic field due to imbalanced chirality of quarks in local parity and charge-parity violating domains in quantum chromodynamics. The experimental measurement of the charge separation is made difficult by the presence of a major background from elliptic azimuthal anisotropy. This background and the CME signal have different sensitivities to the spectator and participant planes, and could thus be determined by measurements with respect to these planes. We report such measurements in Au+Au collisions at a nucleon-nucleon center-of-mass energy of 200 GeV at the Relativistic Heavy-Ion Collider. It is found that the charge separation, with the flow background removed, is consistent with zero in peripheral (large impact parameter) collisions. Some indication of finite CME signals is seen in midcentral (intermediate impact parameter) collisions. Significant residual background effects may, however, still be present.

Measurement of the Sixth-Order Cumulant of Net-Proton Multiplicity Distributions in Au+Au Collisions at sqrt[s_{NN}]=27, 54.4, and 200 GeV at RHIC

According to first-principle lattice QCD calculations, the transition from quark-gluon plasma to hadronic matter is a smooth crossover in the region μ_{B}≤T_{c}. In this range the ratio, C_{6}/C_{2}, of net-baryon distributions are predicted to be negative. In this Letter, we report the first measurement of the midrapidity net-proton C_{6}/C_{2} from 27, 54.4, and 200 GeV Au+Au collisions at the Relativistic Heavy Ion Collider (RHIC). The dependence on collision centrality and kinematic acceptance in (p_{T}, y) are analyzed. While for 27 and 54.4 GeV collisions the C_{6}/C_{2} values are close to zero within uncertainties, it is observed that for 200 GeV collisions, the C_{6}/C_{2} ratio becomes progressively negative from peripheral to central collisions. Transport model calculations without critical dynamics predict mostly positive values except for the most central collisions within uncertainties. These observations seem to favor a smooth crossover in the high-energy nuclear collisions at top RHIC energy.

789 Generation of a Bicycle NK-TICA™, a novel NK cell engaging molecule to enhance targeted tumor cytotoxicity

Background

Natural killer (NK) cells are immune cells that can detect and eliminate tumor cells and bridge innate to adaptive immune responses. Tumor specific activation of NK cells is thus an area of active investigation in immune oncology, but to date has relied on complex biologic modalities (e.g., antibodies, fusion proteins, or cell therapies), each of which has inherent disadvantages in this application. Thus, alternative approaches are warranted. Bicycle® are small (ca. 1.5 kDa), chemically synthetic, structurally constrained peptides discovered via phage display and optimized using structure-driven design and medicinal chemistry approaches. We have now applied this technology to identify Bicycles that bind specifically to the key activating receptors, NKp46 and CD16a. When chemically coupled to tumor antigen binding Bicycles this results in highly potent, antigen-dependent receptor activation and NK cell activation. We term this new class of fully synthetic molecules Bicycle® natural killer- tumor-targeted immune cell agonists (NK-TICAs™) and we will describe their discovery and evaluation in this presentation.

Methods

Using our unique phage display screening platform, we have identified high affinity, selective binders to NKp46 and CD16a. By conjugating the Bicycle® NK cell-engaging binders to a model tumor antigen EphA2-binding Bicycle®, we have developed a bifunctional Bicycle NK-TICA™ molecule. In in vitro functional assays, we evaluated the ability of the Bicycle NK-TICAs™ to induce NK cell activation as well as cell-mediated cytotoxicity and cytokine production in NK-tumor co-culture assays.

Results

We have developed a novel modular compound with high affinity and selectivity to NK cell receptors with specific tumor targeting capability. We demonstrate potent, selective binding of our Bicycles to receptor-expressing cells and the capability of the bifunctional molecule to induce NK cell function. With Bicycle's novel NK-TICA™ compound, we demonstrate engagement of NK cells, specific activation and function of NK cells, and enhanced EphA2-expressing tumor cytotoxicity, in a dose dependent manner.

Conclusions

Bicycle NK-TICAs™ are novel therapeutic agents capable of enhancing the landscape of immune oncology. We hypothesize that utilization of Bicycle NK-TICA™ as a multifunctional immune cell engager will promote modulation of NK cells, and infiltration and anti-tumor activity of NK cells in solid tumors. The data presented here provide initial proof of concept for application of the Bicycle technology to drive NK cell-mediated tumor immunity.

Anticancer immunity induced by a synthetic tumor-targeted CD137 agonist

Background

In contrast to immune checkpoint inhibitors, the use of antibodies as agonists of immune costimulatory receptors as cancer therapeutics has largely failed. We sought to address this problem using a new class of modular synthetic drugs, termed tumor-targeted immune cell agonists (TICAs), based on constrained bicyclic peptides (Bicycles).

Methods

Phage libraries displaying Bicycles were panned for binders against tumor necrosis factor (TNF) superfamily receptors CD137 and OX40, and tumor antigens EphA2, Nectin-4 and programmed death ligand 1. The CD137 and OX40 Bicycles were chemically conjugated to tumor antigen Bicycles with different linkers and stoichiometric ratios of binders to obtain a library of low molecular weight TICAs (MW <8 kDa). The TICAs were evaluated in a suite of in vitro and in vivo assays to characterize their pharmacology and mechanism of action.

Results

Linking Bicycles against costimulatory receptors (e.g., CD137) to Bicycles against tumor antigens (e.g., EphA2) created potent agonists that activated the receptors selectively in the presence of tumor cells expressing these antigens. An EphA2/CD137 TICA (BCY12491) efficiently costimulated human peripheral blood mononuclear cells in vitro in the presence of EphA2 expressing tumor cell lines as measured by the increased secretion of interferon γ and interleukin-2. Treatment of C57/Bl6 mice transgenic for the human CD137 extracellular domain (huCD137) bearing EphA2-expressing MC38 tumors with BCY12491 resulted in the infiltration of CD8+ T cells, elimination of tumors and generation of immunological memory. BCY12491 was cleared quickly from the circulation (plasma t_1/2 in mice of 1–2 hr), yet intermittent dosing proved effective.

Conclusion

Tumor target-dependent CD137 agonism using a novel chemical approach (TICAs) afforded elimination of tumors with only intermittent dosing suggesting potential for a wide therapeutic index in humans. This work unlocks a new path to effective cancer immunotherapy via agonism of TNF superfamily receptors.

An Assay for Periplasm Entry Advances the Development of Chimeric Peptide Antibiotics

The treatment of infection by Gram-negative bacteria is increasingly challenging as resistance to existing antibiotics spreads. Constrained peptides, selected for high target specificity and affinity via library display technologies, are an emerging therapeutic modality in many disease areas and may be a fertile source of new antibiotics. Currently, the utility of constrained peptides and other large molecules as antibiotics is limited by the outer membrane (OM) barrier of Gram-negative bacteria. However, the addition of certain moieties to large molecules can confer the ability to cross the OM; these moieties function as intramolecular trans-OM "vectors". Here, we present a method to systematically assess the carrying capacity of candidate trans-OM vectors using a real-time luminescence assay ("SLALOM", Split Luciferase Assay for Live monitoring of Outer Membrane transit), reporting on periplasmic entry. We demonstrate the usefulness of our tools by constructing a 3800 Da chimeric compound composed of a constrained bicyclic peptide (Bicycle) with a periplasmic target, linked to an intramolecular peptide vector; the resulting chimera is a broad-spectrum inhibitor of pathogenic Gram-negative bacterial growth.

Prevalence of iron deficiency in 62,685 women of seven race/ethnicity groups: The HEIRS Study

Background

Few cross-sectional studies report iron deficiency (ID) prevalence in women of different race/ethnicity and ages in US or Canada.

Materials and methods

We evaluated screening observations on women who participated between 2001–2003 in a cross-sectional, primary care-based sample of adults ages ≥25 y whose observations were complete: race/ethnicity; age; transferrin saturation; serum ferritin; and HFE p.C282Y and p.H63D alleles. We defined ID using a stringent criterion: combined transferrin saturation <10% and serum ferritin <33.7 pmol/L (<15 μg/L). We compared ID prevalence in women of different race/ethnicity subgrouped by age and determined associations of p.C282Y and p.H63D to ID overall, and to ID in women ages 25–44 y with or without self-reported pregnancy.

Results

These 62,685 women included 27,079 whites, 17,272 blacks, 8,566 Hispanics, 7,615 Asians, 449 Pacific Islanders, 441 Native Americans, and 1,263 participants of other race/ethnicity. Proportions of women with ID were higher in Hispanics and blacks than whites and Asians. Prevalence of ID was significantly greater in women ages 25–54 y of all race/ethnicity groups than women ages ≥55 y of corresponding race/ethnicity. In women ages ≥55 y, ID prevalence did not differ significantly across race/ethnicity. p.C282Y and p.H63D prevalence did not differ significantly in women with or without ID, regardless of race/ethnicity, age subgroup, or pregnancy.

Conclusions

ID prevalence was greater in Hispanic and black than white and Asian women ages 25–54 y. p.C282Y and p.H63D prevalence did not differ significantly in women with or without ID, regardless of race/ethnicity, age subgroup, or pregnancy.

Abstract 4479: BT8009: A bicyclic peptide toxin conjugate targeting Nectin-4 (PVRL4) displays efficacy in preclinical tumor models

We have identified a Nectin-4 targeting peptide for delivery of cytotoxic agents to Nectin-4 expressing tumors. Nectin-4 is a cell adhesion molecule, that is highly expressed in certain tumor types, including bladder, TNBC and NSCLC, but has a restricted distribution in normal tissue. Bicycles® are small (1.5kDa) fully synthetic, structurally constrained, peptide drugs that combine the affinity of antibodies with the pharmacokinetic properties of small molecules. The Bicycle phage display platform was utilised to rapidly identify a high affinity (18 nM) and highly selective bicyclic Nectin-4 binding peptide. Synthetic modification of the initial lead peptide improved affinity (0.3 nM), hydrophilicity and stability. The optimised peptide is conjugated through an inert sarcosine spacer chain and a cleavable linker to the toxin MMAE, to form the Bicycle Toxin Conjugate (BTC) BT8009. Once bound to cell surface Nectin-4, the linker system is cleaved by peptidases (e.g. cathepsin B) upregulated in the tumor micro environment. Full structure of BT8009 will be disclosed within the presentation. Fluorescence polarisation and surface plasmon resonance show BT8009 has low nanomolar affinity (3nM) for Nectin-4 and high selectivity (&gt;1000 fold) over Nectins 1-3, and the 5 nectin-like, family members. Good affinity for the cognate native protein is maintained across the preclinical safety species. High content imaging of cultures of MDA-MB-468 cells, demonstrates binding of the BTC to cell membrane. In vivo, BT8009 is well tolerated in mouse and rat and shows regressions across a range of cell and patient derived xenograft models. Efficacy correlates with the expression level of Nectin-4 on the tumor cells, and the dose delivered. In the MDA-MB-468 (TNBC) CDX model full tumor regression was seen with weekly i.v. administration of 3 mg/k g i.v. (4 doses), with no tumor regrowth out to 70 days post last dose. Similar efficacy was seen in two NSCLC PDX models (adenocarcinoma and squamous cell carcinoma) with full regression attained in both. Near full regression was seen in a squamous cell esophageal cancer PDX. Larger tumors show a similar degree of sensitivity to the BTC, with rapid tumor regression from a volume of 800 mm3. As a small peptide BT8009 undergoes rapid clearance from the plasma with minimal exposure to non-targeted organs. After a single dose, MMAE has been shown to be retained within tumor tissue in excess of 60 h, at exposure levels significantly greater than corresponding plasma and other tissue levels. Bicycle Toxin Conjugates represent a novel treatment modality for nectin-4 expressing tumors with excellent efficacy in several mouse xenograft models.

Citation Format: Mike Rigby, Paul Beswick, Gemma Mudd, Katerine Van Rietschoten, Liuhong Chen, Sophie M. Watcham, Heather Allen, Amy Brown, Helen Harrison, Gavin Bennett, Phil Jeffrey, Peter U. Park, Maria Koehler, Nicholas Keen. BT8009: A bicyclic peptide toxin conjugate targeting Nectin-4 (PVRL4) displays efficacy in preclinical tumor models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4479.

Abstract P2-06-11: Sortilin targeted therapy in breast cancer with elevated progranulin expression

Background: A major challenge concerning breast cancer therapy is the occasional lack of effects using drugs that target cancer cells unspecifically. One possible explanation for this treatment failure is the existence of the small subpopulation of breast cancer stem cells that are believed to be more resistant towards conventional therapy and possesses the ability to drive tumor formation and disease progression. Cytokines secreted by nearby cells and other factors in the surrounding tumor microenvironment further stimulate the cancer cells, contributing to a heterogeneous and potentially more treatment resistant tumor. Thus, a more specific treatment approach targeting the breast cancer stem cell niche is crucial in preventing disease recurrences. In a cytokine screen, we identified progranulin as one of the main compounds secreted from cells exposed to hypoxia, leading to cancer stem cell propagation. Progranulin is involved in biological processes such as wound healing, inflammation and cancer progression. Progranulin and its receptor sortilin are known to be highly expressed in subgroups of breast cancer and are further associated with a clinically aggressive phenotype.

Methods/Results: By carrying out a number of in vitro and in vivo like screening assays, we demonstrate that progranulin influences the stem cell population in breast cancer and is responsible for spreading a cancer stem cell promoting signal to normoxic tumor areas. In breast cancer, progranulin induces a dedifferentiation process in the receiving cancer cells and expression of cancer stem cell markers together with an EMT-associated gene expression profile, leading to cancer stem cell expansion. By using siRNA and pharmacological inhibition of sortilin, we show that sortilin is a functional receptor of progranulin and is responsible for driving progranulin induced breast cancer stem cell propagation. Supporting the role of progranulin in cancer progression, administration of progranulin in immunocompromised mice induce lung metastasis in our breast cancer xenograft models. The use of different approaches for blocking sortilin, such as sortilin inhibitors, down-modulators or sortilin-targeted antibodies can prevent this dedifferentiation process, both in vitro and in vivo, making the tumor cells less aggressive and metastatic.

Conclusion: Targeting progranulin through its associated receptors is a potential therapeutic strategy for the treatment of patients with breast tumors having elevated progranulin or sortilin expression. By inhibiting the secretion based breast cancer progression, we could possibly block the formation of metastasis and cancer cell infiltration.

Citation Format: Berger K, Rhost S, Hughes E, Harrison H, Rafnsdottir S, Jacobsson H, Gregersson P, Magnusson Y, Fitzpatrick P, Andersson D, Ståhlberg A, Landberg G. Sortilin targeted therapy in breast cancer with elevated progranulin expression [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P2-06-11.

The effect of an e-learning module on health sciences students' venipuncture skill development

Introduction

Venipuncture is a psychomotor skill required in many healthcare professions. E-learning could be used to overcome current barriers in face-to-face learning in healthcare education such as insufficient classroom space or qualified instructors. We sought to evaluate the effectiveness of an e-learning module on students' performance when used in addition to in-class training.

Methods

Overall, 224 health sciences students were approached to participate in this pilot study. Recruited students were divided into control and study groups. The control group received only in-class training, whereas the study group had access to the e-learning module in addition to in-class learning. Both groups were evaluated on their self-confidence using a Likert scale, academic competence using a multiple-choice questionnaire, and psychomotor competence from video skill recordings using an in-house rubric. Nonparametric, independent sample Mann-Whitney tests were performed to evaluate differences between groups.

Results

Overall, 114 students provided written informed consent; 84 students (control: n = 50, study: n = 34) participated in at least one component of the study. Significantly higher (p = 0.017) academic competence scores were observed in the study group. Significantly higher confidence levels were also observed postintervention for both the control (p = 0.0025) and study (p = 0.0011) groups; however, no significant differences were found between the study and control groups before (p = 0.441) or after (p = 0.883) intervention. Finally, no significant differences (p = 0.428) were observed for psychomotor skills between the study arms.

Conclusion

Our results suggest that there is potential for e-learning to increase the academic competence of students when used in conjunction with traditional learning; however, further research is needed to determine its efficacy on psychomotor skills.

A Fabry-Pérot interferometer with wire-grid polarizers as beamsplitters at terahertz frequencies

The design of a compact Fabry-Pérot interferometer (FPi) and results of the experimental studies carried out using the device are presented. Our FPi uses freestanding wire-grid polarizers (WGPs) as beamsplitters and is suitable for use at terahertz (THz) frequencies. The FPi was studied at the LUCX facility, KEK, Japan, and an 8 MeV linear electron accelerator was used to generate coherent Smith-Purcell radiation. The FPi was designed to be easy to align and reposition for experiments at linear accelerator facilities. All of the components used were required to have a flat or well understood frequency response in the THz range. The performance of the FPi with WGPs was compared to that of a Michelson interferometer and the FPi is seen to perform well. The effectiveness of the beamsplitters used in the FPi is also investigated. Measurements made with the FPi using WGPs, the preferred beamsplitters, are compared to measurements made with the FPi using silicon wafers as alternative beamsplitters. The FPi performs well with both types of beamsplitter in the frequency range used (0.3-0.5 THz). The successful measurements taken with the FPi demonstrate a compact and adaptable interferometer that is capable of analyzing THz radiation over a broad frequency range. The scheme is particularly well suited for polarization studies of THz radiation produced in an accelerator environment.

Assessment of the Target Engagement and D-Serine Biomarker Profiles of the D-Amino Acid Oxidase Inhibitors Sodium Benzoate and PGM030756

Irregular N-methyl-D-aspartate receptor (NMDAR) function is one of the main hypotheses employed to facilitate understanding of the underlying disease state of schizophrenia. Although direct agonism of the NMDAR has not yielded promising therapeutics, advances have been made by modulating the NMDAR co-agonist site which is activated by glycine and D-serine. One approach to activate the co-agonist site is to increase synaptic D-serine levels through inhibition of D-amino acid oxidase (DAO), the major catabolic clearance pathway for this and other D-amino acids. A number of DAO inhibitors have been developed but most have not entered clinical trials. One exception to this is sodium benzoate which has demonstrated efficacy in small trials of schizophrenia and Alzheimer's disease. Herein we provide data on the effect of sodium benzoate and an optimised Takeda compound, PGM030756 on ex vivo DAO enzyme occupancy and cerebellar D-serine levels in mice. Both compounds achieve high levels of enzyme occupancy; although lower doses of PGM030756 (1, 3 and 10 mg/kg) were required to achieve this compared to sodium benzoate (300, 1000 mg/kg). Cerebellar D-serine levels were increased by both agents with a delay of approximately 6 h after dosing before the peak effect was achieved. Our data and methods may be useful in understanding the effects of sodium benzoate that have been seen in clinical trials of schizophrenia and Alzheimer's disease and to support the potential clinical assessment of other DAO inhibitors, such as PGM030756, which demonstrate good enzyme occupancy and D-serine increases following administration of low oral doses.

Abstract 1167: Development of BT1718, a novel Bicycle Drug Conjugate for the treatment of lung cancer

BT1718 is a Bicycle Drug Conjugate (BDC®) comprising a constrained bicyclic peptide (Bicycle®) that binds with high affinity and specificity to membrane type 1-matrix metalloprotease (MT1-MMP; MMP14) covalently linked through a hindered disulfide linker to the potent anti-tubulin agent DM1. MT1-MMP is involved in normal tissue remodeling and is also expressed in tumor associated stromal cells. However, overexpression is linked to increased tumor aggression and metastasis. Specifically, over-expression of MT1-MMP is also associated with poor clinical prognosis and shorter survival times in patients with NSCLC and a range of other solid tumors. The Bicycle MT1-MMP binding element within BT1718 was identified using a proprietary phage display peptide technology consisting of highly diverse phage libraries of linear amino acid sequences constrained into two loops by a central tri-functional chemical scaffold. These MT1-MMP binding Bicycles exhibit a profound affinity and specificity, more often associated with monoclonal antibodies, whilst their low molecular weight (1.5-3 kDa), akin to that of a small molecule, aids in rapid extravasation and tumor penetration. Together these attributes make Bicycles an ideal format for the targeted delivery of cytotoxic payloads. We evaluated the ability of BT1718 to bind to and kill tumor cells in vitro and in vivo in a panel of tumor cells. BT1718 demonstrated MT1-MMP target-specific binding and MT1-MMP-dependent cell killing of lung tumor cells in vitro as well as efficacy across a panel of lung tumor xenograft mouse models. For example, in the Met-amplified squamous NSCLC lung EBC-1 model, complete regressions were observed in all mice at doses as low as 5 mg/kg (iv) twice weekly and across a range of other dosing schedules, from daily to weekly. MT1-MMP-dependent activity was demonstrated by blocking target specific interactions through co-administration of an excess of unconjugated Bicycle binder, which inhibited tumour regression, or a non-binding Bicycle, which had no effect. Further evaluation in patient-derived lung xenograft (PDX) models indicates a similar activity to that seen in cell-line derived xenografts, with efficacy seen from 3mg/kg twice weekly and rapid full regression of tumors at higher doses. The molecular attributes of these Bicycles: rapid tumor penetration and specific binding, makes them ideal therapeutics for targeted delivery of toxins as Bicycle drug conjugates (BDCs). The small size of the BDC may offer a significant advantage to other targeted cytotoxic approaches such as antibody-drug conjugates due to rapid extravasation and improved tumor penetration. BT1718, a Bicycle Drug Conjugate, shows potent anti-tumor activity in human lung tumor xenograft models and IND-enabling studies are underway.

Citation Format: Gavin Bennett, Robert Lutz, Peter Park, Helen Harrison, Kevin Lee. Development of BT1718, a novel Bicycle Drug Conjugate for the treatment of lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1167. doi:10.1158/1538-7445.AM2017-1167

Abstract 3719: Bicyclic peptides for PET imaging of MT1-MMP expressing tumors

The Bicycle® technology is based on repertoires of short peptides displayed on the surface of bacteriophages which can be modified with homo-trifunctional organochemical scaffolds, thus creating large diverse libraries of constrained, bicyclic peptides. These large combinatorial libraries have been extensively used for iterative selections to identify high affinity binding peptides to a wide array of targets, including receptors, interleukins and proteases.

Bicyclic peptides are chemically synthesized macrocyclic entities with drug-like properties that exhibit sub-nanomolar affinities and exquisite selectivity towards targets. Unlike biologics, their synthetic nature allows facile modulation of metabolic and pharmacokinetic properties, as well as site-specific conjugation to effector molecules such as fluorophores, radionuclides, and cytotoxic drugs.

In the present work, novel phage display derived bicyclic peptides were identified targeting the matrix metalloproteinase 14 (also known as MT1-MMP), a tumor associated surface protein overexpressed in a variety of cancers (i.e. lung, breast). A prototype bicyclic peptide with high affinity to MT1-MMP (Kd at ~1 nM) was identified, and confocal microscopy using fluoresceinated bicyclic peptide derivatives shows target-dependent internalisation in MT1-MMP+ cells. In the in vivo mouse, selective tumor binding in an MT1-MMP+ xenograft model is demonstrated for a DOTA conjugate loaded with Ga-68 or Lu-177. Upon proteolytic optimization of the prototype bicycle peptide, a striking enhancement in tumor signal is observed in biodistribution studies. Compared to radiolabeled antibodies directed against the same target, the lead compound showed fast background clearance (&lt; 1 %ID/g for all organs apart from kidneys) resulting in high imaging contrast in µPET studies as early as 30 minutes post injection. Importantly, most of the non-tumor associated bicyclic peptide rapidly clears into the bladder.

Together, tumor targeting bicyclic peptides can, through their small size and high selectivity, facilitate efficient penetration and visualization of tumors in vivo, demonstrating their potential as diagnostic imaging agents in profiling and therapeutic management of patients.

Citation Format: Daniel Teufel, Helen Harrison, Spencer Campbell, Catherine Stace, Edward Walker, Robert J. Lutz, Peter Park, Matthias Eder, Ulrike Bauder-Wüst, Ursula Schierbaum, Karin Leotta, Klaus Kopka, Uwe Haberkorn. Bicyclic peptides for PET imaging of MT1-MMP expressing tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3719. doi:10.1158/1538-7445.AM2017-3719

Abstract 5144: BT1718, a novel bicyclic peptide-maytansinoid conjugate targeting MT1-MMP for the treatment of solid tumors: Design of bicyclic peptide and linker selection

Bicycles® are novel binding agents comprising small bicyclic peptides (1.5-3 KDa) constrained via a chemical scaffold, selected for high affinity and selectivity to targets of interest. MT1 (MMP14/MT1-MMP) is a membrane-associated metalloprotease overexpressed in many solid tumours and is implicated in tumor invasion and metastasis. MT1 expression positively correlates with poor prognosis.

Phage libraries containing 1015 unique peptide sequences were post-translationally cyclized with thiol-reactive scaffold and used in an optimized, high-throughput selection process to identify Bicycles® to the hemopexin domain of MT1. Additional iterative rounds of directed phage based screening were used to optimize affinity and off-phage non-natural amino acids were introduced at select positions to improve plasma stability to generate the lead Bicycle binder. The lead anti-MT1 Bicycle was further modified with a sarcosyl spacer to form N241. N241 binds specifically to the hemopexin domain of MT1 with a Kd of approximately 2 nM with no binding observed to the catalytic domain of the protease nor to any of the related MMP family members tested. Importantly and in contrast to most antibodies, N241 binds with similar affinity to MT1 from multiple species including rodent, dog and non-human primate.

Since the expected rapid tumor penetration and specific binding of these small peptidyl-binders makes them ideal for use in targeted delivery approaches, a series of Bicycle drug conjugates (BDCs) were prepared; N241 was conjugated to potent maytansinoid cytotoxics via linkers which varied in their cleavability. Though all the BDCs maintained high affinity for MT1, efficacy toward MT1-positive human tumor mouse xenografts varied with linker stability. BDCs with the most stable linkers were the least active suggesting that optimal tumor activation was obtained with linkers that could be cleaved more rapidly. Due to the rapid clearance and limited systemic exposure of these small-targeting BDCs, only the most labile linker showed toxicity in the mouse studies. Of the BDCs tested, BT1718, composed of N241 and DM1 conjugated via the SPP linker, demonstrated an optimal therapeutic index. Potent anti-tumor efficacy with BT1718 was observed across a panel of MT1-positive xenografts with complete tumor regressions observed in most models at doses that were well tolerated. In one example, HT-1080 fibrosarcoma subcutaneous xenografts were intraveneously treated with BT1718 when the tumor size had reached approximately 180 mm3. BT1718 given at 3 mg/kg once a week resulted in tumor stasis while BT1718 given at 10 mg/kg once a week or 3 mg/kg twice a week induced complete regression.

In summary, BT1718, a highly active, targeted drug conjugate with unique pharmacological properties is a promising therapeutic candidate for the treatment of MT1-MMP-positive solid tumors.

Citation Format: Helen Harrison, Gavin Bennett, Diane Blakeley, Amy Brown, Spencer Campbell, Liuhong Chen, Robert J. Lutz, Silvia Pavan, Katerine van Rietschoten, Daniel Teufel, Peter U. Park, Kevin Lee. BT1718, a novel bicyclic peptide-maytansinoid conjugate targeting MT1-MMP for the treatment of solid tumors: Design of bicyclic peptide and linker selection [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5144. doi:10.1158/1538-7445.AM2017-5144

Robotic Mammosphere Assay for High-Throughput Screening in Triple-Negative Breast Cancer

In order to identify novel treatment principles specifically affecting cancer stem cells in triple-negative breast cancer, we have developed a high-throughput screening method based on the mammosphere and anoikis resistance assays allowing us to screen compounds using a functional readout. The assay was validated against manual protocols and through the use of positive controls, such as the response to hypoxia and treatment with the known cancer stem cell-targeting compound salinomycin. Manual and robotic procedures were compared and produced similar results in cell handling, cell cultures, and counting techniques, with no statistically significant difference produced from either method. The variance between samples processed manually versus robotically was no greater than 0.012, while Levene's test of significance was 0.2, indicating no significant difference between mammosphere data produced manually or robotically. Through the screening of 989 FDA-approved drugs and a follow-up screen assessing the antineoplastic subgroup, we have identified three therapeutic compounds with the ability to modulate the breast cancer stem cell fraction in the triple-negative breast cancer cell line MDA-MB-231, highlighting their potential usage as stem cell-specific adjuvant treatments.

Variations of the paranasal sinuses in Melanesians as observed by CT

Studies have reported the incidence of anatomical variants of the paranasal sinuses for specific populations with a view to helping surgeons avoid possible complications during functional endoscopic sinus surgery. Some have found significant variation when comparing different populations. The current study has used computed tomography (CT) scans to observe variations in the paranasal sinuses in a non-random sample of museum skulls of Melanesians, a racial group that has not previously been studied in this respect. The incidence of variants found were: agger nasi cells 59.5%, concha bullosa 41.5%/o, Haller's air cells 31.7%, internal carotid artery bulge in the sphenoid sinus 23.8%/, supraorbital cells 16. 7%, paradoxical curvature of the mid-dle turbinate 7.5% and pneumatization of crista galli 7.1%.Because of contradictory findings in the literature as to the incidence of such variations between racial groups the authors are able to make only limited meaningful comparisons between their subjects and other such groups.

Potential nonresponse bias in a clinical examination after initial screening using iron phenotyping and HFE genotyping in the hemochromatosis and iron overload screening study

BACKGROUND

Little is known about the factors affecting participation in clinical assessments after HEmochromatosis and IRon Overload Screening.

METHODS

Initial screening of 101,168 primary care patients in the HEmochromatosis and IRon Overload Screening study was performed using serum iron measures and hemochromatosis gene (HFE) genotyping. Using iron phenotypes and HFE genotypes, we identified 2256 cases and 1232 controls eligible to participate in a clinical examination. To assess the potential for nonresponse bias, we compared the sociodemographic, health status, and attitudinal characteristics of participants and nonparticipants using adjusted odds ratios (ORs) and 95% confidence interval (CI).

RESULTS

Overall participation was 74% in cases and 52% in controls; in both groups, participation was highest at a health maintenance organization and lowest among those under 45 years of age (cases: OR = 0.68; 95% CI 0.53, 0.87; controls: OR = 0.59; 95% CI 0.44, 0.78). In controls only, participation was also lower among those over 65 years of age than the reference group aged 46-64 (OR = 0.64; 95% CI 0.47, 0.88). Among cases, participation was higher in HFE C282Y homozygotes (OR = 3.98; 95% CI 2.60, 6.09), H63D homozygotes (OR = 2.79; 95% CI 1.23, 6.32), and C282Y/H63D compound heterozygotes (OR = 1.82; 95% CI 1.03, 3.22) than in other genotypes, and lower among non-Caucasians and those who preferred a non-English language than in Caucasians and those who preferred English (p < 0.0001).

CONCLUSIONS

Subjects with greatest risk to have iron overload (C282Y homozygotes; cases > or =45 years; Caucasians) were more likely to participate in a postscreening clinical examination than other subjects. We detected no evidence of strong selection bias.

The offer they can't refuse: parents and perinatal treatment decisions

Despite a widespread myth of parental autonomy in decision-making for extremely preterm neonates, families in the United States are often not given access to accurate information about the consequences of preterm birth, resuscitation and treatment, or about their ethical options. Professional, philosophical, and financial incentives for hospitals and neonatologists to provide intensive treatment may trump parental wishes in delivery rooms and neonatal units. Parents may also be intimidated by the atmosphere of intensive care and by the behavior of committed staff. Prenatal advance directives allow parents to receive information on outcomes, treatments, and options, including palliative care, 'on their own turf' and as a part of routine prenatal counseling. The use of directives and other techniques for transparency in obstetric and neonatal care could improve the process of informed parental choice.

Mammary development, carcinomas and progesterone: role of Wnt signalling

The mammary gland begins development during embryogenesis but after exposure to hormonal changes during puberty and pregnancy undergoes extensive further development. Hormonal changes are key regulators in the cycles of proliferation, differentiation, apoptosis and remodelling associated with pregnancy, lactation and involution following weaning. These developmental processes within the breast epithelium can be explained by the presence of a long-lived population of tissue-specific stem cells. The longevity of these stem cells makes them susceptible to accumulating genetic change and consequent transformation. The ovarian steroid progesterone, acting via the secreted factor Wnt4, is known to be essential for side branching of the mammary gland. One function of Wnt proteins is self-renewal of adult tissue stem cells, suggesting that progesterone may exert its effects within the breast, at least partly, by regulating the mammary stem cell population.

Predictors of Belief That Genetic Test Information About Hemochromatosis Should Be Shared with Family Members

We queried 101,951 white, Hispanic, black, Asian, American Indian (i.e., American Indian or Alaska Native in the United States and North American Indian, Metis, or Inuit in Canada) and Pacific Islander (including Native Hawaiian) adults who agreed to be genotypically and phenotypically screened for hemochromatosis as part of the Hemochromatosis and Iron Overload Screening (HEIRS) study about their views on sharing genetic test information with family members. Multiple logistic regression (adjusting for study site, age group, race/ethnicity, preferred language, gender, education group, income group, SF-36 General Health and Mental Health subscales, perceived benefits and limitations of genetic testing, and belief that genetic testing is a good idea) evaluated independent predictors of responding "Strongly Agree" or "Agree" versus "Disagree" or "Strongly Disagree" to the statement "Information about a person's genetic risk should be shared with family members". Agreement that genetic risk information should be shared with family members was high (93% in the overall sample of 78,952 who answered this question), but differed among racial/ethnic groups. Hispanics were significantly less likely to agree that genetic test information should be shared with family members (i.e., 88% versus 92% or more among all other ethnicities). The relationship of perceived limitations and benefits of testing, gender, and age group to the belief that information should be shared differed among racial/ethnic groups, with Spanish-preferring Hispanics being the most different from other subgroups.

Hemochromatosis. Common genes, uncommon illness?

OBJECTIVE

To increase family physicians' awareness of the prevalence of hemochromatosis and to suggest strategies for diagnosis and management of hemochromatosis with the goal of decreasing the development of associated life-threatening conditions.

QUALITY OF EVIDENCE

A MEDLINE search from January 1966 to January 2002 using the MeSH term hemochromatosis/therapy found no randomized controlled trials. A further search from January 1990 to January 2002, using the heading hemochromatosis and subheadings diagnosis, epidemiology, genetics, and therapy, found articles with level II evidence (case-control and cross-sectional studies) and level III evidence (descriptive studies and reports from expert committees). Articles were selected based on clinical relevance.

MAIN MESSAGE

Hemochromatosis is the most common hereditary condition in populations of Northern European descent, affecting three to five people per thousand. Many of these people remain undiagnosed with this condition. The iron overload associated with hemochromatosis can lead to serious, life-threatening conditions, such as diabetes, hepatic cirrhosis, primary liver cancer, and cardiomyopathy. Family physicians can screen patients they suspect are at risk of hemochromatosis with simple indirect serum iron measurements (transferrin saturation and serum ferritin) and with widely available genetic tests (C282Y and H63D). Studies of families can help uncover further cases of hemochromatosis; population screening is currently under study.

CONCLUSION

Family physicians can facilitate early diagnosis of hemochromatosis by maintaining a high index of suspicion in patients with early signs or symptoms or in high-risk groups, and screening these patients for hemochromatosis.