GPVI inhibition by glenzocimab synergistically inhibits atherosclerotic plaque-induced platelet activation when combined with conventional dual antiplatelet therapy

Introduction

Aspirin and a potent platelet P2Y12 inhibitor, such as prasugrel or ticagrelor, are not always sufficient to prevent thrombus formation in patients with ST-elevation MI (STEMI), leading to “slow flow” or “no reflow” effects after stenting. GPIIb/IIIa inhibitors, such as eptifibatide, may help in this setting, but are not used routinely due to their bleeding risk. GPVI has critical roles in thrombosis and a minimal role in haemostasis. Here we tested whether depletion of GPVI has effects on thrombus formation after MI in an animal model and investigated the effects of a novel platelet GPVI inhibitor, glenzocimab (a Fab fragment of a monoclonal antibody), on platelet activation and thrombus formation when combined with aspirin and ticagrelor.

Methods

We used intravital microscopy in a murine model of ST-elevation myocardial infarction and ischaemia-reperfusion injury to investigate microvascular thrombosis. We investigated the antithrombotic effects of adding glenzocimab (previously known as ACT017) to blood from healthy donors and 20 patients with ACS treated with aspirin and ticagrelor. We compared the effect of glenzocimab with the GPIIb/IIIa inhibitor eptifibatide ex-vivo. We stimulated platelets with collagen and atherosclerotic plaque material that was sourced from patients undergoing carotid endarterectomy. We investigated effects on platelet aggregation, spreading, signalling, adhesion, thrombin generation, thrombus formation and clot stability ex vivo.

Results

Genetic depletion of GPVI in an animal model of myocardial infarction reduced microvascular thrombosis. Ex vivo, aspirin and ticagrelor partially inhibited atherosclerotic plaque-induced platelet aggregation (assessed by multiple electrode aggregometry) by 48% compared to control (34±3 vs. 65±4 U; P<0.001; Figure 1). Atherosclerotic plaque-induced platelet aggregation, adhesion, secretion and activation were critically dependent on platelet GPVI activation and were potently inhibited by glenzocimab. Glenzocimab alone reduced atherosclerotic plaque-induced platelet aggregation by 75% compared to control (16±4 vs. 65±4 U; P<0.001; Figure 1) and by over 95% when combined with aspirin and ticagrelor (3±1 vs 65±4 U; P<0.001; Figure 1). Furthermore, glenzocimab provided multiple synergistic antithrombotic effects when added to the blood of aspirin and ticagrelor-treated patients with ACS ex vivo. Glenzocimab and the GPIIb/IIIa inhibitor, eptifibatide, had many similar antithrombotic effects but glenzocimab had less effect on mechanisms of general haemostasis compared to eptifibatide, as assessed by ROTEM (Figure 2).

Conclusions

The addition of glenzocimab to aspirin and ticagrelor provides synergistic inhibition of multiple critical mechanisms of atherothrombosis. Glenzocimab and the GPIIb/IIIa inhibitor, eptifibatide, share many similar antithrombotic effects, although glenzocimab has less impact on mechanisms involved in haemostasis compared to eptifibatide.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Academy of Medical Sciences UK Clinical Lecturer Starter GrantRoyal Embassy of Saudi Arabia

Natriuretic peptides predict future heart failure and cardiovascular death in an unselected population of patients presenting to hospital: interactions with atrial fibrillation

Aims

Natriuretic peptides are routinely quantified to diagnose heart failure (HF). Their concentrations are also elevated in atrial fibrillation (AF). To clarify their interpretation, we measured natriuretic peptides in unselected patients with cardiovascular conditions and related their concentrations to AF and HF status and to outcomes.

Methods and results

Consecutive patients with cardiovascular conditions presenting to a large teaching hospital (median age 70 [IQR 60–78] years, 40% women) underwent clinical assessment, 7-day ECG-monitoring, and echocardiography to diagnose AF and HF. N-terminal pro B-type natriuretic peptide (NT-proBNP) was centrally quantified. Clinical characteristics and NT-proBNP concentrations were related to HF hospitalization or cardiovascular death. Follow-up data was available in 1611/1616 patients (99.7%) and analysis performed at 2.5 years. Based on a literature review, four NT-proBNP groups were defined (<300pg/ml, 300–999pg/ml, 1000–1999pg/ml and ≥2000pg/ml).

Multivariate Cox proportional hazards analysis of the composite outcome against AF and HF phenotype groups. This was adjusted for confounding factors including age, sex, race, body mass index, hypertension, diabetes, coronary artery disease, severe valvular heart disease, left bundle branch block, hyponatraemia, urea, haemoglobin, estimated glomerular filtration rate, NT-proBNP, medical treatment with ACE inhibitors or angiotensin receptor blockers, beta-blockers, diuretic (thiazide or loop diuretics), and anticoagulants (novel oral anticoagulant or vitamin K antagonist). Cox proportional hazards analysis adjusted for confounding variables for the composite outcome against baseline NT-proBNP concentration ranges was also performed in each patient group based on AF and HF status.

HF hospitalization or cardiovascular death increased from patients with neither AF nor HF (36/488, 3.2/100 person-years), to 55/353 (7.1/100 person-years) in patients with AF only, 91/366 (12.1/100 person-years) in patients with HF only, and, 128/404 (17.7/100 person-years) in patients with AF plus HF (p<0.001). Higher NT-proBNP concentrations predicted the outcome in patients with AF only (C-statistic 0.82 [95% CI 0.77 to 0.86], p-value<0.001) and in other phenotype groups (C statistic in AF plus HF 0.66 [95% CI 0.61 to 0.70], p-value<0.001)). Sensitivity analyses confirmed these findings.

Conclusion

Elevated NT-proBNP concentrations predict future HF events in patients with AF irrespective of the presence of HF. In line with previous studies in HF, an NT-proBNP threshold of 1000 pg/ml is useful to identify high-risk patients with AF whether or not they are diagnosed with HF at the time of assessment. Pending external validation, these findings encourage the routine quantification of NT-proBNP in the initial assessment of patients with AF.

Funding Acknowledgement

Type of funding sources: Public grant(s) – EU funding. Main funding source(s): 1) This study was partially supported by European Union BigData@Heart and 2) CATCH ME (Characterising Afib by Translating its Causes into Health Modifiers in the Elderly)

Cross-sectional and longitudinal characterisation of cognitive function and outcomes in patients presenting to hospital with cardiovascular risk factors

Background/Introduction

Cardiovascular (CV) diseases including atrial fibrillation and arteriosclerosis are associated with impaired cognitive function. Cognitive dysfunction can impact the process of shared clinical decision making, reduce adherence to polypharmacy, and decrease quality of life. The prevalence of cognitive dysfunction in contemporary patients with CV diseases and its implication on future CV events is not well known.

Purpose

We 1) quantified cognitive function in patients presenting to hospital with CV diseases, 2) identified clinical variables and blood biomarkers associated with cognitive dysfunction, and 3) quantified the hazard of abnormal cognitive function for predicting MACCE (major adverse CV and cerebrovascular events).

Methods and results

Of 1625 consecutive patients presenting acutely to a large teaching hospital with CV diseases, 614 patients (median age [Q1, Q3] 68 [58, 76] years; 66% male) who completed the Montreal Cognitive Assessment (MoCA) were analysed. The median [Q1, Q3] MoCA score was 25 points [21, 27]. 360 patients (59%) had an abnormal score (<26). At baseline, patients with abnormal scores were more likely to be female (odds ratio, OR [95% confidence intervals], 1.874 [1.287, 2.728]), have BMI<30 (OR 0.584 [0.410, 0.831]), heart failure (OR 1.492 [1.043, 2.135]), diabetes (OR 2.212 [1.529, 3.199]), chronic kidney disease (CKD-EPI<60 ml/min, OR 1.553 [1.021, 2.361]), and have more CV co-morbidities (OR per additional co-morbidity 1.415 [1.246, 1.605]). Amongst 12 CV biomarkers tested, elevated Bone Morphogenetic Protein 10 (OR 1.325 [1.022, 1.719]) and Growth Differentiation Factor 15 (OR 1.419 [1.054, 1.912]) increased odds of abnormal scores.

Cox proportional hazards model adjusted for competing risk of non-CV death assessed the relationship between abnormal cognitive function and MACCE (stroke, TIA, myocardial infarction, hospitalisation for heart failure, CV death). Follow-up time ranged from 2.7 to 6.1 years. Patients were censored at 2.5 years for this analysis. 130 out of 614 patients experienced a MACCE (21%) and 71 had a non-CV death (12%). Patients with abnormal MoCA scores were at higher risk for MACCE (subhazard ratio, sHR [95% CI] 1.827 [1.253, 2.664]). The hazard remained significant after adjustment for age, sex, obesity, atrial fibrillation, stroke, heart failure, hypertension, coronary artery disease, diabetes, peripheral artery disease and renal dysfunction (sHR 1.367 [1.056, 2.326]; Figure). All-cause mortality was 1.785 times higher for those with abnormal MoCA scores [1.061, 3.002].

Conclusion

In this study, 3 out of 5 patients with CV diseases had abnormal MoCA scores at baseline. Abnormal cognitive scores significantly predicted patients who went on to experience a MACCE within 2.5 years of follow-up. These observations call for further research and action to provide additional diagnostics, support and early intervention to address cognitive dysfunction in CV patients.

Funding Acknowledgement

Type of funding sources: Public grant(s) – EU funding. Main funding source(s): EU H2020 CATCH ME Cumulative incidence function

Identification of novel biomarkers for predicting atrial fibrillation outcomes in patients with cardiovascular risk factors

Funding Acknowledgements

Type of funding sources: Public grant(s) – EU funding. Main funding source(s): CATCH ME European Commission H2020 grant (no. 633196)

Background

Several novel blood biomarkers were recently found to reflect underlying pathophysiology implicated in atrial fibrillation (AF). These biomarkers could be used for stratifying patients at risk of developing AF or AF-related adverse events.

Purpose

We combined 9 clinical risk factors and 12 biomarkers to model composite outcomes of 1) incident AF, hospitalisation for arrhythmias, and cardiovascular death in sinus rhythm patients at risk of AF, and 2) recurrent AF, hospitalisation for arrhythmias, and cardiovascular death in patients with AF.

Methods

1455 patients presenting acutely to hospital with either diagnosed AF (n = 648) or sinus rhythm and ≥2 CHA2DS2-VASc risk factors (n = 807, silent AF ruled out by 7-day ECG monitoring) were followed up for two years. Outcomes were collected from linked hospital episode statistics (HES) and Office of National Statistics (ONS) data from NHS Digital. We univariately evaluated 12 cardiovascular biomarkers quantified from EDTA plasma collected at baseline (ANG2, BMP10, CA125, CRP, ESM1, FABP3, FGF23, GDF15, IGFBP7, IL6, NTproBNP, Troponin T). Two predictive models combining clinical characteristics and biomarkers were developed for each patient group, using Cox regression with backward elimination and considering non-cardiovascular death as a competing risk.

Results

In sinus rhythm patients (n = 117/807 with outcome), elevated BMP10, ANG2, CA125, IGFBP7, NTproBNP univariately predicted the composite outcome (adjusted for age, sex, body mass index (BMI), eGFR, heart failure, stroke/TIA, hypertension, diabetes, coronary artery disease – see Figure part A). In the combined model, age, prior stroke/TIA, coronary artery disease, ANG2, IGFBP7 and NTproBNP predicted the outcome (C-statistic [95% confidence interval (CI)] 0.733 [0.683, 0.784]).

In patients with AF (n = 193/648 with outcome), elevated BMP10, ANG2, CA125, troponin T, GDF15, IGFBP7, NTproBNP univariately predicted the composite outcome (adjusted for same variables as above – see Figure part B). In the combined model, high BMI, low eGFR, hypertension, IGFBP7, NTproBNP and troponin T were predictive of the composite outcome (C-statistic [95% CI]: 0.643 [0.596, 0.689]).

Conclusion

Combinations of clinical risk factors and biomarkers were predictive of two-year AF-related adverse events in sinus rhythm patients at risk of AF and in patients with AF. These markers could be used to identify patients for more intensive follow-up or therapy. IGFBP7 and NTproBNP were present in both models, implicating pathways involved with cardiac overload, inflammation, and oxidative stress. These findings call for external validation of these markers and prospective evaluation in at-risk populations. Abstract Figure. Biomarkers predicting 2-year AF outcomes

High-Throughput Screening and Triage Assays Identify Small Molecules Targeting c-MYC in Cancer Cells

While c-MYC is well established as a proto-oncogene, its structure and function as a transcription factor have made c-MYC a difficult therapeutic target. To identify small-molecule inhibitors targeting c-MYC for anticancer therapy, we designed a high-throughput screening (HTS) strategy utilizing cellular assays. The novel approach for the HTS was based on the detection of cellular c-MYC protein, with active molecules defined as those that specifically decreased c-MYC protein levels in cancer cells. The assay was based on a dual antibody detection system using Förster/fluorescence resonance energy transfer (FRET) and was utilized to detect endogenous c-MYC protein in the MYC amplified cancer cell lines DMS273 and Colo320 HSR. The assays were miniaturized to 1536-well plate format and utilized to screen the GlaxoSmithKline small-molecule collection of approximately 2 million compounds. In addition to the HTS assay, follow-up assays were developed and used to triage and qualify compounds. Two cellular assays used to eliminate false-positive compounds from the initially selected HTS hits were (1) a cellular toxicity assay and (2) an unstable protein reporter assay. Three positive selection assays were subsequently used to qualify compounds: (1) 384-well cell cycle flow cytometry, (2) 384-well cell growth, and (3) c-MYC gene signature reverse transcription quantitative PCR (RT-qPCR). The HTS and follow-up assays successfully identified three compounds that specifically decreased c-MYC protein levels in cancer cells and phenocopied c-MYC siRNA in terms of cell growth inhibition and gene signatures. The HTS, triage, and three compounds identified are described.

Decreased right ventricular strain before LVAD implantation is associated with adverse early outcome

Objectives

Right ventricular (RV) failure occurring after left ventricular assist device (LVAD) implantation is associated with increased mortality.

Purpose

We sought to determine whether RV strain by echocardiography predicts outcomes following LVAD.

Methods

Consecutive patients who underwent continuous flow LVAD placement at our clinic between February 2007 and October 2018 were included. Patients with complex congenital heart disease and arrhythmogenic right ventricular cardiomyopathy were excluded. Baseline characteristics, pre-operative hemodynamic catheterization (1 week) transthoracic echocardiography (1 month) measurements were obtained from the medical record. Speckle tracking RV free wall longitudinal 2D strain was measured using TomTec Imaging System. Univariate and multivariable analysis performed to identify predictors of mortality following LVAD.

Results

The study group was comprised of 323 patients (mean age 60.8±11.5, 79.9% male) of which 256 had adequate image quality for RV strain. RV strain was impaired in most patients (mean −11.7±3.47). RV strain of −8.1% was identified as predictive of poor outcomes. RV strain did not correlate with other measures of RV dysfunction including pulmonary artery pulsatility index (PAPi) and RVFAC. After adjusting for PAPi, RA pressure, and clinical cumulative risk scores (Matthews, Kormos and Lietz-Miller) impaired RV free wall longitudinal strain (OR: 1.14; 95% CI: 1.01–1.29, p=0.025), tricuspid regurgitation (by vena contracta width (TRvc) (OR: 1.19; 95% CI: 1.05–1.36, p=:0.0021) and smaller LVEDD (OR: 0.95; 95% CI: 0.92–0.99, p:0.023) predicted 30-day all-cause mortality and RV failure. Decreased RV free wall strain also predicted peri-operative mortality (22.58% vs. 4.89%, p=0.0003) and prolonged inotropic support (247.0.±277.4 vs. 122.8±139.3, p=0.024).

Conclusions

RV free wall strain is a non-invasive independent predictor of 30-day adverse outcomes (RV failure or all-cause mortality) Routine measurement of RV free strain may identify those patients at highest risk for early and long term mortality following LVAD.

Funding Acknowledgement

Type of funding source: None

Prognostic utility of cardiopulmonary exercise testing indices in arrhythmogenic right ventricular cardiomyopathy

Introduction

Cardiopulmonary exercise testing (CPET) has an established role in the clinical evaluation of exercise intolerance and in the risk stratification of patients with heart failure. There is limited data assessing its prognostic utility in the evaluation of patients with Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC). The predisposition of patients with ARVC for ventricular arrhythmias and sudden cardiac death has led to recommendations for exercise restrictions and limits our understanding of how the impairment in oxygen extraction and cardiac output impact disease progression and outcomes in these patients.

Purpose

We examined the association between CPET indices and event free survival (time to mortality or cardiac transplantation) in patients with Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC).

Methods

Patients with definite ARVC based on 2010 task force criteria and genetically positive were enrolled into our institutional ARVC registry. 43 patients underwent CPET and have been included in our analyses. Indications for testing included: Evaluation of exercise-induced palpitations/arrhythmias or syncope (37%), pharmacotherapy optimization (28%), heart failure evaluation (19%), and ARVC management decisions (16%). CPET data (peak oxygen consumption (pVO2), respiratory exchange ratio (RER), and ventilatory efficiency (VE/VCO2) were assessed in patients at time of initial evaluation. Median follow-up time was 4.9 years (IQR 9 years).

Results

126 patients were studied (age 43.7+ 15 yrs; 41% women; LVEF 57+ 11%; 15% with LVEF <50%) and 43 underwent CPET evaluation. 41 patients (95%) performed at near maximal effort (RER >1) and no fatal events were reported during testing. During the follow up period, the outcome (death or cardiac transplantation) occurred in 31 patients. On Kaplan Meier analysis, pVO2 ≤14 mL/kg/min was associated with worse outcomes (unadjusted p<0.001). Peak oxygen consumption (pVO2) ≤14 mL/kg/min and ventilatory efficiency (VE/VCO2) >34 were associated with shorter event free survival (HR 5.58, p=0.002 and HR 5.56 p=0.005, respectively). After adjusting for age, sex, and right ventricular function, the association between peak oxygen consumption (pVO2) and event free survival remained significant (p=0.02).

Conclusions

In patients with ARVC, peak oxygen consumption (pVO2) was a prognostic indicator of worse outcomes. Our findings suggest a potential role for pVO2 in disease surveillance and early assessment for advanced heart failure therapies.

Figure 1. KM plot pVO2 & event free survival

Funding Acknowledgement

Type of funding source: Other. Main funding source(s): Mayo Clinic

Novel KV7 ion channel openers for the treatment of epilepsy and implications for detrusor tissue contraction

Neuronal voltage-gated potassium channels, K_V7s, are the molecular mediators of the M current and regulate membrane excitability in the central and peripheral neuronal systems. Herein, we report novel small molecule K_V7 openers that demonstrate anti-seizure activities in electroshock and pentylenetetrazol-induced seizure models without influencing Rotarod readouts in mice. The anti-seizure activity was determined to be proportional to the unbound concentration in the brain. K_V7 channels are also expressed in the bladder smooth muscle (detrusor) and activation of these channels may cause localized undesired effects. Therefore, the impact of individual K_V7 isoforms was investigated in human detrusor tissue using a panel of K_V7 openers with distinct activity profiles among K_V7 isoforms. KCNQ4 and KCNQ5 mRNA were highly expressed in detrusor tissue, yet a compound that has significantly reduced activity on homomeric K_V7.4 did not reduce detrusor contraction. This may suggest that the homomeric K_V7.4 channel plays a less significant role in bladder contraction and further investigation is needed.

Coal mine dust lung disease in the modern era

Coal workers' pneumoconiosis (CWP), as part of the spectrum of coal mine dust lung disease (CMDLD), is a preventable but incurable lung disease that can be complicated by respiratory failure and death. Recent increases in coal production from the financial incentive of economic growth lead to higher respirable coal and quartz dust levels, often associated with mechanization of longwall coal mining. In Australia, the observed increase in the number of new CWP diagnoses since the year 2000 has necessitated a review of recommended respirable dust exposure limits, where exposure limits and monitoring protocols should ideally be standardized. Evidence that considers the regulation of engineering dust controls in the mines is lacking even in high-income countries, despite this being the primary preventative measure. Also, it is a global public health priority for at-risk miners to be systemically screened to detect early changes of CWP and to include confirmed patients within a central registry; a task limited by financial constraints in less developed countries. Characteristic X-ray changes are usually categorized using the International Labour Office classification, although future evaluation by low-dose HRCT) chest scanning may allow for CWP detection and thus avoidance of further exposure, at an earlier stage. Preclinical animal and human organoid-based models are required to explore potential re-purposing of anti-fibrotic and related agents with potential efficacy. Epidemiological patterns and the assessment of molecular and genetic biomarkers may further enhance our capacity to identify susceptible individuals to the inhalation of coal dust in the modern era.

Abstract C38: Novel allosteric IDH1 mutant Inhibitors for differentiation therapy of acute myeloid leukemia

Mutations in the isocitrate dehydrogenase 1 (IDH1) gene are known driver mutations in acute myeloid leukemia (AML) and other cancer types. AML is hallmarked by a differentiation block and patient outcomes remain poor, especially for patients above 60 years of age who typically do not tolerate high dose chemotherapy and stem cell transplantation, leading to cure rates below 20%. Hence the development of novel targeted therapies for treatment of AML subtypes are required. Of note, inhibitors of mutants of the closely related IDH2 gene as well as IDH1 have recently been described and show promising pre-clinical and early phase clinical activity. However, the specific molecular and functional effects of IDH1 inhibitors in AML, including in primary patients' cells, have not been reported yet.

Here, we report the development of novel allosteric inhibitors of mutant IDH1 for differentiation therapy of acute myeloid leukemia. A high-throughput biochemical screen targeting an IDH1 heterodimer composed of R132H and WT IDH1 led to the identification of a tetrahydropyrazolopyridine series of inhibitors. Structural and biochemical analyses revealed that these novel compounds bind to an allosteric site that does not contact any of the mutant residues in the enzymes active site and inhibit enzymatic turnover. The enzyme complex locked in the catalytically inactive conformation inhibits the production of the oncometabolite 2-hydroxyglutarate (2-HG). In biochemical studies, we observed potent inhibition of several different clinically relevant R132 mutants in the presence or absence of the cofactor NADPH, accompanied by significant decrease in H3K9me2 levels.

Treatment of primary IDH1 mutant AML patients' cells ex vivo uniformly led to a decrease in intracellular 2-HG, abrogation of the myeloid differentiation block, increased cell death and induction of differentiation both at the level of leukemic blasts and immature stem-like cells. Allosteric inhibition of IDH1 also led to a decrease in leukemic blasts in an in vivo xenotransplantation model. At the molecular level, enhanced reduced representation bisulfite sequencing showed that treatment with allosteric IDH1 inhibitors led to a significant reversal of the DNA cytosine hypermethylation pattern induced by mutant IDH1, accompanied by gene expression changes of key sets of genes and pathways, including “Cell Cycle”, “G1/S transition”, “Cellular growth and proliferation”, and “Cell death and survival”.

Taken together, our findings provide novel insight into the effects of inhibition of mutant IDH1 in primary AML patients' cells and open avenues for future investigations with these and other novel allosteric inhibitors for targeting IDH1 mutants in leukemia and possibly in other cancers.

Citation Format: Ujunwa C. Okoye-Okafor, Boris Bartholdy, Jessy Cartier, Enoch Gao, Beth Pietrak, Alan R. Rendina, Cynthia Rominger, Chad Quinn, Angela Smallwood, Ken Wiggall, Alexander Reif, Stan Schmidt, Hongwei Qi, Huizhen Zhao, Gerard Joberty, Maria Faelth-Savitski, Marcus Bantscheff, Gerard Drewes, Chaya Duraiswami, Pat Brady, Swathi-Rao Narayanagari, Ileana Antony-Debre, Kelly Mitchell, Heng Rui Wang, Yun-Ruei Kao, Maximilian Christopeit, Luis Carvajal, Laura Barreyro, Elisabeth Paietta, Britta Will, Nestor Concha, Nicholas D. Adams, Benjamin Schwartz, Michael T. McCabe, Jaroslav Maciejewski, Amit Verma, Ulrich Steidl. Novel allosteric IDH1 mutant Inhibitors for differentiation therapy of acute myeloid leukemia. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr C38.

New IDH1 mutant inhibitors for treatment of acute myeloid leukemia

Neomorphic mutations in isocitrate dehydrogenase 1 (IDH1) are driver mutations in acute myeloid leukemia (AML) and other cancers. We report the development of new allosteric inhibitors of mutant IDH1. Crystallographic and biochemical results demonstrated that compounds of this chemical series bind to an allosteric site and lock the enzyme in a catalytically inactive conformation, thereby enabling inhibition of different clinically relevant IDH1 mutants. Treatment of IDH1 mutant primary AML cells uniformly led to a decrease in intracellular 2-HG, abrogation of the myeloid differentiation block and induction of granulocytic differentiation at the level of leukemic blasts and more immature stem-like cells, in vitro and in vivo. Molecularly, treatment with the inhibitors led to a reversal of the DNA cytosine hypermethylation patterns caused by mutant IDH1 in the cells of individuals with AML. Our study provides proof of concept for the molecular and biological activity of novel allosteric inhibitors for targeting different mutant forms of IDH1 in leukemia.

Clinical implementation of NIPT - technical and biological challenges

Non-invasive prenatal testing (NIPT) for fetal aneuploidy detection is increasingly being offered in the clinical setting. Whereas the majority of tests only report fetal trisomies 21, 18 and 13, genome-wide analyses have the potential to detect other fetal, as well as maternal, aneuploidies. In this review, we discuss the technical and clinical advantages and challenges associated with genome-wide cell-free fetal DNA profiling.

Clinical implementation of NIPT - technical and biological challenges

Non-invasive prenatal testing (NIPT) for fetal aneuploidy detection is increasingly being offered in the clinical setting. Whereas the majority of tests only report fetal trisomies 21, 18 and 13, genome-wide analyses have the potential to detect other fetal, as well as maternal, aneuploidies. In this review, we discuss the technical and clinical advantages and challenges associated with genome-wide cell-free fetal DNA profiling.

Assessing the functional performance of post-call hospital doctors using a Nintendo Wii

Sleep deprivation is an established part of the working life for Non-Consultant Hospital Doctors (NCHDs) in Ireland. Concern exists about the effect of extended NCHD work hours. We utilised a Nintendo Wii to evaluate motor function of NCHDs both prior to their on-call shift and the day afterwards. Data was exported to SPSS ver. 15 for statistical analysis with p < 0.05 considered significant. A total of 72 NCHDs were invited to participate in this study. There was a 62.5% (45) rate of follow-up. Overall 27 (60%) NCHDs were on medical call, with 18 (40%) on surgical call. There was no statistically significant difference between NCHDs pre-and post-call motor assessment scores. The majority of study participants (75.5%, n = 34) had four or more hours sleep. On-call duty allows for a greater than anticipated amount of sleep per on-call shift and therefore has a negligible effect on the motor skills of medical staff.

The team focus on improving blood transfusion

The current literature pertaining to associated morbidity and mortality with homologous blood transfusion in the surgical patient seems to be pointing only in one direction, which is we must start reducing our patients exposure to homologous blood and products. There appears to be ever mounting evidence of increases in infraction, stroke, transfusion related lung injury, infection, and death that authors are associating with transfusion. A number of authors are reporting success in reducing their patients' requirements for homologous transfusion simply by working as a team or what is known as a multidisciplinary approach and following set transfusion protocols and algorithms. At our institution we have taken note of these reports and have taken the first steps in the formation of a Cardiac Surgical Transfusion Management Group where all specialties involved in the decision making process of transfusion in the cardiac surgical patient can have representation and be directly involved in the establishment of protocols, transfusion algorithms, and a transfusion audit system. The main goal of this group is to implement a change in transfusion practice and to assess the impact the change has had on transfusion requirements and make appropriate recommendations to the treating specialists.

Parkinsonism: siblings share Helicobacter pylori seropositivity and facets of syndrome

OBJECTIVE

Given a history of peptic ulcer is more frequent in parkinsonism, to investigate the role of Helicobacter pylori in its pathogenesis and of cross-infection in familial aggregation.

METHODS

Facets of parkinsonism were quantified in 33 elderly subjects with idiopathic parkinsonism and in their 39 siblings with double the number of controls, all obeying inclusion/exclusion criteria. Specific-IgG antibody was assayed.

RESULTS

Siblings, compared with controls, had brady/hypokinesia of gait (P< or =0.002), bradykinesia of hands (P = 0.01), abnormal posture (P = 0.001), rigidity (P < 0.001) and seborrhoea/seborrhoeic dermatitis (P = 0.02). Both parkinsonians and siblings differed from controls in the odds of being H. pylori seropositive [odds ratios 3.04 (95% C.I.: 1.22, 7.63) and 2.94 (1.26, 6.86) respectively, P < 0.02], seropositivity being found in 0.70 of sufferers.

CONCLUSION

Familial transmission of chronic infection plus part of syndrome links Helicobacter with causality. Seropositivity not being universal throughout parkinsonism, consequent on gastric atrophy +/- sporadic antibiotic exposure, might explain less aggressive disease in older sufferers.

Surgical repair of type-A aortic dissection: early and late results in 32 consecutive patients

BACKGROUND

Acute type-A aortic dissection is a surgical emergency. One unit's experience in the surgical repair of type-A aortic dissection is documented.

METHODS

Surgical treatment was undertaken for type-A aortic dissection in 32 consecutive patients between January 1988 and August 1994 at Royal North Shore Hospital. Retrosternal chest pain was the commonest presenting symptom and in four of these cases it was initially misinterpreted as myocardial ischaemia.

RESULTS

A total of 24 patients had signs of aortic incompetence on presentation. Computed tomography (CT) scanning was the commonest modality of definitive diagnosis, but trans-oesophageal echocardiography was used as confirmation wherever possible, and we now consider it the initial, best investigation whenever a diagnosis of dissection is considered. There were 15 supra-coronary ascending aortic replacements, and a further four with aortic valve re-suspension. There were 13 operations of the Bentall's type. The overall 30-day mortality was 19%. The late mortality was 19%, with 62% long-term survival at a mean follow-up of 4.8 years.

CONCLUSION

Early diagnosis and surgical intervention can give excellent palliation and improved life expectancy in acute type-A aortic dissection.