Global longitudinal strain for prediction of mortality in ST-segment elevation myocardial infarction and aortic stenosis patients: two sides of the same coin

OBJECTIVE

Global longitudinal strain (GLS) predicts major adverse events in ST-segment elevation myocardial infarction (STEMI) and aortic stenosis (AS). Different cut-off values and different end-points have been proposed for prognostic stratification. We aimed to verify whether a single GLS cut-off value can be used to identify increased risk of all-cause death in STEMI and AS.

PATIENTS AND METHODS

One-hundred- seventeen successfully treated first STEMI (age 63.8±12.5 yrs, 70% men) and 64 AS (age 80.3±6.9 yrs, 44% men) patients, undergoing echocardiography before discharge and before AS treatment, respectively, were retrospectively analyzed. GLS was analyzed, together with pulmonary artery systolic pressure (PASP), Killip class and Genereux stage. End-point was all-cause death at 6-month follow-up.

RESULTS

All-cause death occurred in 4 (3.4%) STEMI and 5 (7.8%) AS patients (p=ns). AS patients who died had GLS similar to died STEMI patients (9.7±2.1 vs. 11.3±1.7, p=ns). GLS cut-off ≤12% predicted death with 89% sensitivity and 70% specificity (AUC 0.84, p=0.001): STEMI and AS patients with GLS ≤12% had worse survival than STEMI and AS patients with GLS >12% (log-rank p=0.001). At multivariate Cox regression analysis, lower GLS values independently predicted death (HR 0.667, 95% CI 0.451-0.986, p=0.042), and the prediction model was improved when GLS was added to old age, significant comorbidities, PASP and Killip/Genereux stage (χ2 6.691 vs. 1.364, p=0.010).

CONCLUSIONS

Died patients with STEMI and AS show similar values of GLS. A unique cut-off value of GLS can reliably be used to stratify the risk of all-cause death at 6-month follow-up in both two clinical settings.

Left atrial strain analysis improves non-invasive estimation of left ventricular filling pressures in takotsubo syndrome

Background

Takotsubo syndrome (TTS) is associated with a non-negligible risk of in-hospital (IH) complications. Elevated left ventricular filling pressures (LVFP), measured invasively as LV end-diastolic pressure (LVEDP), showed to predict adverse IH outcomes in this population.

Recently, novel indexes of left atrial (LA) function, including LA reservoir and LA pump strain, demonstrated a close correlation with increased LVFP in unselected patients.

Purpose

To assess the ability of LA reservoir and LA pump strain to improve non-invasive estimation of LVFP and to predict IH complications in TTS patients.

Methods

We retrospectively enrolled patients with confirmed TTS diagnosis at invasive left heart catheterization and coronary angiography. LVEDP was assessed invasively at the time of catheterization. Transthoracic echocardiography was performed with 48 hours from hospital admission. IH complications were collected, including occurrence of acute heart failure (pulmonary oedema/cardiogenic shock; Killip class III/IV), death from any cause and life-threatening arrhythmias.

Results

A total of 62 patients were analysed (72.2±10.1 years, female 80%). IH complications occurred in 25 (40.3%). Patients who experienced IH complications had higher LVEDP and lower LVEF, LA reservoir strain and LA pump strain values compared to patients without IH complications (all P≤0.001). At multivariate analysis, EF and LVEDP were independent predictors of worse IH outcomes (P≤0.001 and P=0.004 respectively). Correlation analysis proved that lower values of both LA reservoir and pump strain were associated with increasingly higher LVEDP (r −0.859, P≤0.001 and r −0.848, P≤0.001 respectively). Receiving operating characteristic (ROC) curve analysis showed that the AUC for LVEDP to predict IH complications was 0.814 (95% CI 0.679–0.949, P≤0.001) with an optimal cut-off value of 24.5 mmHg (sensitivity 77%, specificity 53%).

Therefore, we performed ROC curve analysis to compare the ability of LA strain values and standard echocardiographic parameters currently used for non-invasive LVFP assessment to predict LVEDP ≥24.5 mmHg. As a result, we obtained higher AUC for LA reservoir and pump strain [0.909 (95% CI 0.818–0.999, P≤0.001) and 0.889 (95% CI 0.789–0.988, P≤0.001), respectively] vs E/e' 0.800 (95% CI 0.663–0.937, P≤0.001), LAVi 0.666 (P=0.092) and tricuspid regurgitation (TR) peak velocity 0.582 (P=0.596). The incorporation of LA strain values in a multivariable model including E/e' ratio, LAVi and TR peak velocity to predict a LVEDP ≥24.5 mmHg led to a significant incremental predictive value (changes in χ2=11.99; P=0.002).

Conclusion

In patients with TTS, lower LA reservoir and pump strain values correlate with increased LVEDP and improve non-invasive estimation of LVFP. LA strain analysis may be an easy tool to individuate subjects at higher risk of IH complications.

Funding Acknowledgement

Type of funding sources: None.

P59 A COMPLEX PCI IN A CARDIOGENIC SHOCK NSTEMI PATIENT NEEDING PTA AND LEFT VENTRICLE ASSISTANCE

A 72–years–old man, smoker, type 2 DM and hypertension in history, was admitted for NSTEMI complicated by cardiogenic shock; Echocardiogram revealed LV dilatation with severe disfunction (EF 20%), moderate mitral regurgitation; he started inotropic support and high dose diuretics, then he needed dialysis and positioning of a temporary PM. Coronary angiography revealed chronic total occlusion (CTO) of the left anterior descending artery (LADA) and CTO of the right coronary artery (RCA). A first CTO PCI procedure was attempted for the LADA occlusion, with the support of IABP, using an antegrade approach, polimeric wire (ASAHI Fielder) and more penetrating ones (ASAHI Gaia I and II), unable to gain the true lumen beyond the occlusion. A second attempt was planned, with the support of Impella CP device for left ventricle assistance; due to critical stenosis in the right common iliac artery, a PTA with stenting (8/38 mm) was preparatory for that. For the second attempt a dual coronary approach was prepared (6 F Amplatz left 1,0 for RCA and 7 F XB 3,5 for left coronary artery); at first a novel antegrade attempt was pursued with a step–up technique (ASAHI wires: Gladius, Gaia I, II and III, Conquest pro), ineffective to reach the true lumen distally the occlusion. The retrograde approach was then pursued, through a collateral originating from the acute marginal branch of the RCA to the distal segment of LADA, using the Caravel microcatheter with ASAHI wires Sion blue, Sion black, Suoh 03, effective to reach the distal cap of the occlusion, this one passed by the Gladius wire. The ASAHI RG3 externalization wire (330 mm) was then used, entering from the radial access and the amplatz catheter for the RCA, reaching the XB catheter in the left coronary artery through a Guideliner extension catheter, and externalized in the femoral access. IVUS analysis was then used to confirm good wire position and the vessel calibers, so pre–dilatation was done and 3 drug–eluting stents were implanted (2,25/23 + 3,25/38 + 3,5/18 mm) distal–to–proximal overlap, with final post–dilatation, obtaining a good final result on angiography and IVUS. During the 4–hours procedure clinical condition was stable and Impella was removed with a rapid weaning; the double pre–mounted Proglide device was used for femoral hemostasis. 5 days after the patient was discharged, II–III NYHA class, 25% EF. At the 3 months f–up he was asymptomatic in good clinical condition, 30% EF, he refused ICD implant.

Acute hemodynamic impact of transcatheter aortic valve implantation in patients with severe aortic stenosis

Funding Acknowledgements

Type of funding sources: None.

Background. There are limited data about the intraprocedural hemodynamic study performed immediately before and after transcatheter aortic valve implantation (TAVI) in patients with severe aortic stenosis (AS). Purpose. We aimed to evaluate the acute hemodynamic impact of TAVI in patients with severe AS and to investigate invasive and non-invasive parameters predicting all-cause mortality. Methods. A total of 245 consecutive AS patients undergoing TAVI were enrolled. Intraprocedural left heart catheterization (LHC) and echocardiogram before and after TAVI were performed. The clinical endpoint was the death for any cause. Results. LHC after TAVI revealed significant changes in aortic and LV pressures, including indexes of intrinsic myocardial contractility and diastolic function such as positive dP/dT (1128.9 ± 398.7 vs 806.3 ± 247.2 mmHg/sec, p˂0.001; Figure 1A) and negative dP/dT (1310.7± 431.1 vs 1075.1 ± 440.8 mmHg/sec, p˂0.001; Figure 1B). Post TAVI echo showed a significant reduction in LV end diastolic volume index (54.6 ± 18.4 ml/m2 vs 51.7 ± 17.5 ml/m2; p = 0.017; Figure 1C), improvement in left ventricle ejection fraction (from 55 ± 12 to 57.2 ± 10.5%, p˂0.001; Figure 1D) and pulmonary artery systolic pressure (42.1 ± 14.2 vs 33.1 ± 10.7 mmHg, p < 0.001; Figure 1E). After a mean follow-up time interval of 24 months, 47 patients died. Post-TAVI aortic regurgitation (2- 3- 4+) at echocardiography was the only independent predictor of mortality (HR 4.43, C.I. 1,71 – 11,45, p = 0.002; Figure 2). Conclusions. LHC performed immediately before and after prosthesis release offers a unique insight in the assessment ofLV adaptation to severe AS and the impact of TAVI on LV, catching changes in indexes of intrinsic contractility and myocardial relaxation. Aortic regurgitation assessed by echocardiography was the only independent predictor of mortality in patients undergoing TAVI.

FIGURE LEGEND

Figure 1. A-B: Impact of TAVI on haemodynamic parameters: Box plot with median and interquartile ranges of positive dP/dT and negative dP/dT values pre vs post TAVI. C-D-E: Impact of TAVI on echocardiographic parameters: Box plot with median and interquartile ranges of left ventricular end diastolic volume index (LVEDVi), left ventricular ejection fraction (EF) and pulmonary artery systolic pressure (PASP) values pre vs post TAVI.

Figure 2. Kaplan-Meier curves for survival showing that AR (2-3-4+) assessed with echocardiography had the strongest association with mortality. Abstract Figure 1.  Abstract Figure 2.

Right ventricle-pulmonary artery coupling in repaired tetralogy of fallot with pulmonary regurgitation: clinical implications

Funding Acknowledgements

Type of funding sources: None.

Background

The right ventricle-pulmonary artery (RV-PA) coupling is a strong prognostic marker in

several clinical settings, but only few studies focused on its role in repaired Tetralogy of

Fallot (rToF) with pulmonary regurgitation (PR). Aim of this study was to assess

whether differences exist in RV-PA coupling, estimated as by echocardiography,

between patients with rToF and PR with (i-PVR) or without (ni-PVR) indication for

pulmonary valve replacement (PVR).

3

Materials and Methods

The study population included 40 rToF patients allocated to two groups: 20 i-PVR and

20 ni-PVR; 40 healthy controls were also included. All subjects underwent

echocardiogram, while Cardiac magnetic resonance (CMR) was available in 27/40

rToF patients. RV-PA coupling was assessed by echocardiographic TAPSE/PASP and

RV stroke volume/RV end systolic volume (RVSV/RVESV) by CMR.

Results

TAPSE was similar in i-PVR vs ni-PVR (19.0 ± 3.4 vs 18.8 ± 2.7 mm, p = 0.85) while RV-PA coupling

was significantly worse in i-PVR vs ni-PVR (TAPSE/PASP 0.8 ± 0.3 vs 1.1 ± 0.5

mm/mmHg, p = 0.009) as well as in i-PVR vs controls (p = 0.02) while there was no

difference between ni-PVR and controls (p = 0.29). CMR data confirmed the echo

results, with a significant difference in RV-PA coupling between i-PVR and ni-PVR

(RVSV/RVESV 0.9 ± 0.2 vs 1.2 ± 0.3 mL/min/mL, p = 0.01).

Conclusions

This study shows the presence of worse RV-PA uncoupling, despite normal RV systolic

function, in rToF patients with indication to PVR. RV-PA coupling could be a sensitive

marker of a progressive maladaptive RV response to long-standing volume overload in

rToF prior to the onset of clinical symptoms and RV systolic dysfunction. Abstract Figure. example of an i-PVR patient

The Monte Carlo method to build up models of the hydrolysis half-lives of organic compounds

The hydrolysis of organic chemicals such as pesticides, pollutants, or drugs can affect the fate and behaviour of environmental contaminants, so it is of interest to evaluate the stability of substances in water for various purposes. For the registration of organic compounds in Europe, information on hydrolysis must be presented. However, the experimental measurements of all chemicals would require enormous resources, and computational models may become attractive. Applying the CORAL software (http://www.insilico.eu/coral) quantitative structure-property relationships (QSPRs) were built up to model hydrolysis. The 2D-optimal descriptor is calculated with so-called correlation weights for attributes of simplified molecular input-line entry systems (SMILES). The correlation weights are obtained as results of the special Monte Carlo optimization. The nature of (five- and six-member) rings is an important component of this approach. Another important component is the atom pair proportions for nitrogen, oxygen, and sulphur. The statistical quality of the best model is: n = 44, r² = 0.74 (training set); n = 14, r² = 0.75 (calibration set); and n = 12, r² = 0.80 (validation set).

Non invasive ventilation and right ventricle function in cardiogenic pulmonary edema: an echocardiographic perspective to select the "right" ventilatory support

Funding Acknowledgements

Type of funding sources: None.

Background

High-flow nasal cannulae oxygen therapy (HFNCOT) represents a better tolerated alternative to non-invasive pressure support ventilation (NIPSV) for acute cardiogenic pulmonary edema (ACPE) treatment. However, there are still few data on the effect of HFNCOT on cardiac function and hemodynamic.

Purpose

To assess and compare the effects of NIPSV and HFNCOT in ACPE setting on right ventricular (RV) systolic function and on indices of cardiac filling and output, as measured by echocardiography. 

Methods

 This is a cross-over controlled study, enrolling 15 consecutive patients admitted to our Cardiovascular Intensive Care Unit for ACPE and hypoxaemic, normo/hypocapnic acute respiratory failure, with P/F ratio < 200. Each patient received NIPSV, followed by HFNCOT. Full echocardiographic assessment and blood gas analysis (BGA) were performed 40 minutes from onset of each ventilation modality, respectively before NIPSV to HFNCOT switch and before HFNCOT interruption. In particular, RV function parameters, together with RV and atrial strain, were prospectively collected.

Results

 In spite of not significant changes in BGA, RV function was significantly improved under HFNCOT, as compared to NIPSV, as assessed by the following parameters: tricuspid annular plane excursion (TAPSE) (P = 0.001), RV S’ wave (P = 0.007), RV fractional area change (RVFAC) (P = 0.006). Strain analysis confirmed the significant improvement in RV function, with free wall global longitudinal strain (GLS) and free wall and septum GLS significantly higher under HFNCOT, as compared to NIPSV (-21% vs -18% P < 0.001, and -15% vs -19% P = 0.008, respectively,), and a significant increase in right atrial positive longitudinal strain (P < 0.001). 

Conclusions

NIPSV significantly affect RV function making more complex the management of patients presenting with ACPE. In this setting, HFNCOT represents a valuable alternative, providing similar respiratory outcomes while preserving good right ventricle performance.

Pediatric robotic‐assisted laparoscopic ureterocalycostomy: Salient tips and technical modifications for optimal repair

Introduction

Ureterocalycostomy is a necessary option for renal salvage in cases where conventional reconstructions have failed or as a primary option in anatomic situations such as intrarenal pelvis, malrotated, or horseshoe kidney. The primary principle of this procedure is to allow for dependent drainage. Ureterocalycostomy is often difficult due to extensive scar tissue and may be complicated by bleeding in the setting of a normal functioning lower pole cortex, compared to thin renal cortex and poor renal function as seen in end‐spectrum of the obstruction. Identification of a dependent calyx and hemostasis can be difficult when there is a normal cortical thickness. Though the vascular control of hilum is an option, we suggest some simple tips to avoid this step and optimize surgical results. We present our experience and salient technical tips with pediatric robotic‐assisted laparoscopic ureterocalycostomy and provide a step‐by‐step video.

Methods

Four patients underwent robotic‐assisted laparoscopic ureterocalycostomy between the years 2012 and 2016 by a single surgeon. Perioperative outcomes measured included operative time, hospital stay, pain relief, degree of hydronephrosis on postoperative ultrasound at 3 months, and renal scintigraphy as needed. We describe the operative procedure and provide tips on identifying a dependent lower pole calyx with flexible nephroscopy and needle puncture, the use of harmonic scalpel for incision of the lower pole cortex, and anastomosis by pre‐placement of interrupted sutures as the urothelium of the renal calyces is thin and friable.

Results

Patients ranged in age between 11 months and 14 years old. Three of four patients had one prior pyeloplasty, and one patient had two prior pyeloplasties. Mean operative time (incision to closure) was 208 minutes. No Clavien‐Dindo 30‐day complications were encountered and no patients required blood transfusion. Anatomic success was reported in all patients with a mean follow‐up of 4.46 years; however, one patient ultimately required nephrectomy despite patent anastomosis, which would not drain due to a capacious pelvis.

Conclusions

Robotic‐assisted laparoscopic ureterocalycostomy is feasible in re‐operative cases with extensive scaring and in patients with normal lower pole renal cortex. We offer tips to allow for safe and proficient performance of this procedure.

Choice architecture-based prescribing tool for TB preventive therapy: a pilot study in South Africa

Background

All people with HIV who screen negative for active tuberculosis (TB) should receive isoniazid preventive therapy (IPT). IPT implementation remains substantially below the 90% WHO target. This study sought to further understanding of IPT prescription by piloting a simplified prescribing approach.

Setting

Primary care clinics in Matlosana, South Africa.

Design

This was a mixed-methods implementation study.

Methods

Nine providers were recruited and underwent training on 2018 WHO guidelines. A simplified prescribing tool containing antiretroviral therapy (ART) and IPT prescriptions was introduced into the workflow for 2 weeks. Prescription data were collected from file review. Interviews were conducted with prescribers.

Results

During the study period, 41 patients were evaluated for ART initiation; 34 (83%) files used the simplified prescribing tool. Thirty-seven (90%) patients were eligible for same-day ART and IPT initiation, of whom 36 (97%) received IPT prescription. Qualitative interviews identified the following barriers to IPT prescription: cognitive burden, extensive documentation, limited management support, paucity of training, stock-outs, and patient-related factors. Provider acceptability of the tool was favorable, with unanimous recommendation to colleagues on the basis of streamlining documentation and reminding to prescribe.

Conclusions

This simplified prescribing device for IPT was feasible to implement. Streamlining documentation and reminding providers to prescribe can reduce work-flow barriers to IPT provision.

Duchenne muscular dystrophy: preliminary experience with sacubitril-valsartan in patients with asymptomatic left ventricular dysfunction

OBJECTIVE

Duchenne muscular dystrophy (DMD) is an inherited X-linked recessive neuromuscular disease caused by mutations of the dystrophin gene, leading to early and progressive muscle deterioration and dilated cardiomyopathy. The aim of this investigation was to assess whether treatment with sacubitril/valsartan (S/V) is well tolerated and may have beneficial effects in DMD patients with left ventricle (LV) dysfunction.

PATIENTS AND METHODS

We administered S/V to 3 DMD patients (19-29 yeard old) with LV ejection fraction <35% at echocardiography but no symptoms of heart failure. All patients were on optimal medical therapy. S/V was initiated at a very low dose of 12/13 mg/die, after withdrawal of angiotensin-converting enzyme inhibitor therapy, and slowly titrated to the dose of 49/51 mg twice daily or the maximally tolerated dose. Clinical and echocardiographic follow-up was performed after 3, 6 and 12 months.

RESULTS

At baseline, the LV ejection fraction was 32±1%. A significant improvement of LV ejection fraction was observed at 3 months (44.0±6.0%; p<0.05), which was maintained at 6 (45.7±5.0%) and 12 (43.3±3.2%) months (p<0.05 for both). No relevant side effects were reported throughout the period of the study.

CONCLUSIONS

Our preliminary data suggest that, in DMD patients with reduced LV ejection fraction, S/V is safe and may improve LV function.

Localized Nanoresonator Mode in Plasmonic Microcavities

Submicron-thick hexagonal boron nitride crystals embedded in noble metals form planar Fabry-Perot half-microcavities. Depositing Au nanoparticles on top of these microcavities forms previously unidentified angle- and polarization-sensitive nanoresonator modes that are tightly laterally confined by the nanoparticle. Comparing dark-field scattering with reflection spectroscopies shows plasmonic and Fabry-Perot-like enhancements magnify subtle interference contributions, which lead to unexpected redshifts in the dark-field spectra, explained by the presence of these new modes.

QSAR models for biocides: The example of the prediction of Daphnia magna acute toxicity

Biocides are multi-component products used to control undesired and harmful organisms able to affect human or animal health or to damage natural and manufactured products. Because of their widespread use, aquatic and terrestrial ecosystems could be contaminated by biocides. The environmental impact of biocides is evaluated through eco-toxicological studies with model organisms of terrestrial and aquatic ecosystems. We focused on the development of in silico models for the evaluation of the acute toxicity (EC₅₀) of a set of biocides collected from different sources on the freshwater crustacean Daphnia magna, one of the most widely used model organisms in aquatic toxicology. Toxicological data specific for biocides are limited, so we developed three models for daphnid toxicity using different strategies (linear regression, random forest, Monte Carlo (CORAL)) to overcome this limitation. All models gave satisfactory results in our datasets: the random forest model showed the best results with a determination coefficient r² = 0.97 and 0.89, respectively, for the training (TS) and the validation sets (VS) while linear regression model and the CORAL model had similar but lower performance (r² = 0.83 and 0.75, respectively, for TS and VS in the linear regression model and r² = 0.74 and 0.75 for the CORAL model).

P956 Prognostic role of right ventricular hypertrophy in anderson fabry disease

Background

Right ventricular hypertrophy (RVH) is a common finding in Anderson Fabry disease (AFD). In other infiltrative and storage cardiomyopathies right ventricular (RV) involvement may influence prognostic stratification. Nevertheless, the prognostic implications of right ventricle involvement in AFD have never been assessed.

Purpose

Evaluation of the prognostic significance of RVH and RV systolic function in AFD cardiomyopathy.

Methods

Forty-five AFD patients (56% male) with extensive baseline evaluation, including assessment of RVH and RV systolic function, were followed-up for an average of 44.9 ± 8.5 months. RV systolic function was assessed by standard and tissue Doppler echocardiography and quantified using RV fractional area change (RVFAC), tricuspid annular plane systolic excursion (TAPSE) and Systolic tissue Doppler velocity of the tricuspid annulus (RV Sa). Cardiovascular events were defined as new-onset atrial fibrillation, heart failure or pace-maker implantation; renal events were defined as progression to dialysis and/or renal transplantation or significant worsening of glomerular filtration rate; cerebrovascular events were defined as stroke or transient ischemic attack. The outcome was defined as the time to death or the first event in any of the above predefined categories.

Results

Fourteen patients (31.1%) presented RVH, while RV systolic function was normal in all cases. During the follow-up period, 13 patients (28.8%, 11 male) experienced major events including two deaths. Pace-maker implantation (6 cases) was the most common type of event. At univariate analysis several variables were associated with the occurrence of events, including RVH and indexes of RV systolic function. However, at multivariate analysis only proteinuria (HR:8.3, 95% CI: 2.88 to 23.87, p ˂0.001) and LV mass indexed (HR: 1.01, 95% CI: 1.00 to 1.03, p = 0.03) were independent predictors of outcome.

Conclusions

The presence and extension of RVH is not associated with outcome in AFD. Our study confirms that at variance with other infiltrative or storage cardiomyopathies, RV involvement in AFD is an innocent bystander and does not influence prognosis.

P734 Feasibility and accuracy of the new automated software dynamic heart model in an unselected population

Objective

Preliminary studies showed the accuracy of machine learning based automated dynamic quantification of left ventricular (LV) and left atrial (LA) volumes. We aimed to evaluate the feasibility and accuracy of this new Dynamic Heart Model (DHM) software in an unselected population undergoing transthoracic echocardiography (TTE). Methods. We enrolled 91 consecutive unselected patients (80% in sinus rhythm) referred for clinically indicated 2D TTE, who also underwent single 3D TTE image acquisition from the apical 4-chamber view. 2D images were analyzed to measure ejection fraction, LV and LA volumes; 3D images were analyzed using Dynamic Heart Model (DHM) software (Philips Healthcare), which automatically measures chamber volumes throughout the cardiac cycle, resulting in LV and LA volume-time curves. Average time of analysis, feasibility, image quality were recorded and results compared between the 2D and 3D techniques. Results. Quality of the 91 2D TTE images was graded as poor (N = 13), satisfactory (N = 45) and good (N = 33). The use of DHM was feasible in 79/91 cases (87%). The remaining 12 datasets could not be analyzed because of poor images (N = 10) or incorrect automated border detection (N = 2): in these cases, the software did not accurately identify endocardial borders due to LV cavity near obliteration or extreme LA enlargement. When feasible, the boundary position was considered accurate in 61/79 patients (77%), while minor manual correction of the LV/LA borders was needed in the remaining cases. In only 1 case the reconstruction was considered unreliable because it needed major corrections. The overall time required to obtain DHM data was approximately 45 seconds. In all cases in which DHM was used, not only shapes of LV and LA were very well defined, but also functional curves were physiologically plausible. Even in the 13 patients in whom the 2D image was suboptimal, the DHM was not only feasible but also accurate endocardial boundaries in 8 cases, without (N = 5) or with only minimal manual corrections (N = 3). As expected, 3D LV volumes were slightly hige than 2D ones ( EDV 153.9 ± 59.8 vs 121.4 ± 47.3 mL, respectively), while LV EF and LA volumes were similar (EF 58.8 ± 11.8 vs 59 ± 11.8% and LA volume 92 ± 39.3 vs 83.4 ± 32.1 mL, respectively). Conclusions. The new DHM software is quick, feasible and accurate in the majority of unselected patients, including those with suboptimal 2D images or in atrial fibrillation. Introduction of this automated analysis into clinical practice can reduce examination time, while providing reliable information not only on volumes but also on function of the left heart chambers.

P1590 Regional differences in longitudinal strain and response to adenosine stress in patients with myocardial infarction and ST-segment elevation. Results from Extreme trial

Background

Global longitudinal strain (LS) is a sensitive marker of ischemic myocardial damage and predicts adverse left ventricular (LV) remodeling and outcome, independently of infarct size. In healthy subjects, regional LS increases from LV base to apex and enhances under physical or pharmacological stress, while in ST-elevation myocardial infarction (STEMI), response to dobutamine depends on transmurality of necrosis. It is known that coronary flow reserve during adenosine (ADN) is impaired both in ischemic and remote myocardium, but effect of ADN on strain reserve has never been investigated. Similarly, LS response to ADN in ischemic (iLS) and remote (rLS) myocardium and their relative contribution to LV function and remodeling are still unknown.

Methods

61 consecutive patients with first STEMI (26 anterior, 29 inferior, 6 lateral), treated by successful primary percutaneous coronary intervention (PCI) followed by PCI of non-culprit coronary arteries, underwent rest and stress ADN (140 mcg/kg/minutes in 90 seconds) echocardiography at discharge (7 ± 2 days after admission). LV end-diastolic volume indexed for body surface area (EDV), ejection fraction (EF) and wall motion score index (WMSI) were measured at rest, while GLS, iLS and rLS analysis was performed both at rest and during stress. Ischemic and remote myocardium was allocated, by standard LV segmentation, basing on the culprit coronary artery.

Results

Significant differences existed among anterior, inferior and lateral STEMI in median (iQr) EDV [52 (45-59) vs 45 (36-51) vs 48 (45–56) ml, respectively, p=.034 overall], EF [47 (37-58) vs 58 (53–61) vs 56 (46-60)%, respectively, p=.002 overall], WMSI [1.63 (1.38–2) vs 1.25 (1.19-1.47) vs 1.41 (1.30-1.75), respectively, p=.001 overall]. GLS differed among anterior, inferior and lateral STEMI both at rest [13.75 (11.63-16.1) vs 19.5 (17.15-22.4) vs 17.85 (17.02-19), respectively, p&lt;.001 overall] and during ADN [14 (12.35-16.15) vs 19.5 (17.9–22.05) vs 15.95 (14.40-19.48), respectively, p&lt;.001], but did not change within groups. No differences were found between rest and stress iLS in any group. Similarly, rLS remained unchanged in anterior and inferior STEMI, and impaired after ADN in lateral STEMI [15.90 (11.45-18) at stress vs 16.8 (15.25-19.2) at rest, p=.043]. Inferior STEMI showed better iLS than anterior STEMI both at rest [17 (15.1–19.9) vs 13.75 (11.46-16.92), respectively, p=.001] and during stress [16.2 (15–20.4) vs 14.42 (12.67-15.83), respectively, p=.001].

Conclusions

In the subacute phase of STEMI, GLS, iLS and rLS are heterogeneous and depend on infarct site. After ADN, there is no strain reserve in ischemic neither in remote myocardium. This may reflect regional differences in the response of microcirculation and myocardium to ischemia or may underlie pre-existing pathophysiological differences in the coronary circulation

TRPML1 links lysosomal calcium to autophagosome biogenesis through the activation of the CaMKKβ/VPS34 pathway

The lysosomal calcium channel TRPML1, whose mutations cause the lysosomal storage disorder (LSD) mucolipidosis type IV (MLIV), contributes to upregulate autophagic genes by inducing the nuclear translocation of the transcription factor EB (TFEB). Here we show that TRPML1 activation also induces autophagic vesicle (AV) biogenesis through the generation of phosphatidylinositol 3-phosphate (PI3P) and the recruitment of essential PI3P-binding proteins to the nascent phagophore in a TFEB-independent manner. Thus, TRPML1 activation of phagophore formation requires the calcium-dependent kinase CaMKKβ and AMPK, which increase the activation of ULK1 and VPS34 autophagic protein complexes. Consistently, cells from MLIV patients show a reduced recruitment of PI3P-binding proteins to the phagophore during autophagy induction, suggesting that altered AV biogenesis is part of the pathological features of this disease. Together, we show that TRPML1 is a multistep regulator of autophagy that may be targeted for therapeutic purposes to treat LSDs and other autophagic disorders.

It was known that prolonged TRMPL1 activation induces TFEB translocation and upregulates autophagic gene regulation. Here, the authors show that acute TRMPL1 activation also induces autophagy through VPS34 and by lysosomal calcium release independent of TFEB.

P1502Age- and gender-specific prognostic cutoff values of coronary flow velocity reserve in vasodilator stress echocardiography

Background

Coronary flow velocity reserve (CFVR) of left anterior descending artery is useful for risk stratification during stress echocardiography (SE) as an add-on to regional wall motion abnormalities (RWMA), but the age-and sex-dependence of prognostic cutoff values remains unclear.

Purpose

To provide sex and age-specific prognostic cut-off values which may be needed to account for the physiologic decline of CFVR with age, and sex-related differences in resting flow.

Methods

In an observational, prospective, multicenter, registry study design, we enrolled from August 2003 to August 2017 in 4 Italian cardiology referral centers with accredited, quality-controlled stress echo laboratory a consecutive sample of 5,577 patients (of them, 2,284 women and 110 aged ≥85 years) referred to the SE lab for known or suspected coronary artery disease, after exclusion of patients with inadequate acoustic window (n=295), premature test interruption (n=105), and lost to follow-up (n=173).All underwent dual imaging (RWMA and CFVR) dipyridamole SE (0.84 mg/kg over 6') and were followed-up. All-cause death and non-fatal myocardial infarction were the main outcome measures. Median follow-up of 20 months (1st quartile 8, 3rd quartile 43 months),

Results

There were 649 hard events (236 deaths and 413 non-fatal myocardial infarctions), 288 of which occurred in women and 38 in patients ≥85 years. With a ROC analysis, the best prognostic cut-off value for CFVR was almost the same for men (2.03) and women (2.02) and consistent across all age strata (<45 years: 2.03; 45–54 years: 2.04; 45–64 years: 2.03; 65–74 and 75–84 years: 2.0) except for the very elderly (>85 years) who showed an optimal value of 1.90. Independent prognostic indicators were RWMA (HR=5.42, 95% CI=2.42–12.15; p<0.0001) and reduced CFVR (HR=3.26, 95% CI 2.27–3.90; p<0.0001) in patients aged <85 years, and RWMA (HR=5.42, 95% CI=2.42–12.15; p<0.0001) in patients aged >85 years.

Best prognostic cut-off value of CFVR

Conclusion

A sex-independent cut-off value of CFVR ≤2.0 provides the optimal risk stratification across all age groups, except those >85 years in whom a lower cut-off <1.90 is needed. Risk stratification is more effective for all age groups when CFVR is combined with RWMA.

Diagnostic role of echocardiography in patients admitted to the emergency room with suspect no-ST-segment elevation acute myocardial infarction

OBJECTIVE

We investigated whether echocardiography may help identify, among patients admitted with a suspect of non-ST-segment elevation acute myocardial infarction (NSTEMI), those with athero-thrombotic coronary artery disease (CAD).

PATIENTS AND METHODS

We studied consecutive patients admitted with a clinical suspect of first NSTEMI. Echocardiography was assessed within 24 hours from admission. Patients were divided into two groups, according to the results of coronary angiography: 1) patients with obstructive stenosis (≥ 50%) and/or images of thrombosis in one or more coronary arteries (CAD group); 2) patients with no evidence of obstructive coronary arteries (NOCAD group).

RESULTS

Of 101 patients enrolled in the study, 53 (52.5%) showed obstructive CAD and 48 (47.5%) NOCAD. At echocardiographic examination, regional wall motion abnormalities were found in 52.8% of patients in the CAD group and 43.7% in the NOCAD group (p=0.43). Left ventricle ejection fraction was 56.4±6.8 vs. 54.7±9.8% (p=0.30) and wall motion score index was 1.16±0.26 vs. 1.21±0.32 (p=0.39) in the two groups, respectively. A multivariable logistic regression independent predictors of obstructive CAD included age, male gender, typical angina, diabetes and hypertension.

CONCLUSIONS

Our data showed that, in patients with acute chest pain and increased serum troponin T concentration, routine standard echocardiography does not significantly improve the diagnostic accuracy for the presence of obstructive CAD.

Cleaning interfaces in layered materials heterostructures

Heterostructures formed by stacking layered materials require atomically clean interfaces. However, contaminants are usually trapped between the layers, aggregating into randomly located blisters, incompatible with scalable fabrication processes. Here we report a process to remove blisters from fully formed heterostructures. Our method is over an order of magnitude faster than those previously reported and allows multiple interfaces to be cleaned simultaneously. We fabricate blister-free regions of graphene encapsulated in hexagonal boron nitride with an area ~ 5000 μm², achieving mobilities up to 180,000 cm² V^-1 s^-1 at room temperature, and 1.8 × 10⁶ cm² V^-1 s^-1 at 9 K. We also assemble heterostructures using graphene intentionally exposed to polymers and solvents. After cleaning, these samples reach similar mobilities. This demonstrates that exposure of graphene to process-related contaminants is compatible with the realization of high mobility samples, paving the way to the development of wafer-scale processes for the integration of layered materials in (opto)electronic devices.

Long Spin Diffusion Length in Few-Layer Graphene Flakes

We report a spin valve with a few-layer graphene flake bridging highly spin-polarized La_{0.67}Sr_{0.33}MnO_{3} electrodes, whose surfaces are kept clean during lithographic definition. Sharp magnetic switching is verified using photoemission electron microscopy with x-ray magnetic circular dichroism contrast. A naturally occurring high interfacial resistance ∼12  MΩ facilitates spin injection, and a large resistive switching (0.8  MΩ at 10 K) implies a 70-130  μm spin diffusion length that exceeds previous values obtained with sharp-switching electrodes.

Assessment of in silico models for acute aquatic toxicity towards fish under REACH regulation

We evaluated the performance of eight QSAR in silico modelling packages (ACD/ToxSuite™, ADMET Predictor™, DEMETRA, ECOSAR, TerraQSAR™, Toxicity Estimation Software Tool, TOPKAT™ and VEGA) for acute aquatic toxicity towards two species of fish: Fathead Minnow and Rainbow Trout. For the Fathead Minnow, we compared model predictions for 567 substances with the corresponding experimental values for 96-h median lethal concentrations (LC50). Some models gave good results, with r² up to 0.85. We also classified the predictions of all the models into four toxicity classes defined by CLP. This permitted us to assess other parameters, such as the percentage of correct predictions for each class. Then we used a set of 351 substances with toxicity data towards Rainbow Trout (96-h LC50). In this case the predictability was unacceptable for all the in silico models. The calculated r² gave poor correlations (≤0.53). Another analysis was performed according to chemical classes and for mode of action. In the first case, all the classes show a high percentage of correct predictions, in the second case only narcotics and polar narcotics were predicted with good confidence. The results indicate the possibility of using in silico methods to estimate aquatic toxicity within REACH regulation, after careful evaluation.

Comparison of in silico models for prediction of Daphnia magna acute toxicity

Eight in silico modelling packages were evaluated and compared for the prediction of Daphnia magna acute toxicity from the viewpoint of the European legislation on chemicals, REACH. We tested the following models: Discovery Studio (DS) TOPKAT, ACD/Tox Suite, ADMET Predictor, ECOSAR (Ecological Structure Activity Relationships), TerraQSAR, T.E.S.T. (Toxicity Estimation Software Tool) and two models implemented in VEGA on 480 industrial compounds for 48-h median lethal concentrations (LC50) to D. magna, matching them with experimental values. The quality of the estimates was compared using a standard statistical review and an additional classification approach in which the hazard predictions were grouped using well-defined regulatory criteria. The regression parameters, correlation coefficient being the most influential, showed that four models (ADMET Predictor, DS TOPKAT, TerraQSAR and VEGA DEMETRA) had similar reliability. These performed better than the others, but the coefficient of determination was still low (r2 around 0.6), considering that at least half the predicted compounds were inside the training sets. Additionally, we grouped the results in four defined toxicity classes. TerraQSAR™ gave 60% of correct classifications, followed by DS TOPKAT, ADMET Predictor™ and VEGA DEMETRA, with 56%, 54% and 48%, respectively. These results highlight the challenges associated with developing reliable and easily applied acceptability criteria for the regulatory use of QSAR models to D. magna acute toxicity.

Measurement of filling-factor-dependent magnetophonon resonances in graphene using Raman spectroscopy

We perform polarization-resolved Raman spectroscopy on graphene in magnetic fields up to 45 T. This reveals a filling-factor-dependent, multicomponent anticrossing structure of the Raman G peak, resulting from magnetophonon resonances between magnetoexcitons and E(2g) phonons. This is explained with a model of Raman scattering taking into account the effects of spatially inhomogeneous carrier densities and strain. Random fluctuations of strain-induced pseudomagnetic fields lead to increased scattering intensity inside the anticrossing gap, consistent with the experiments.

Electroluminescence in single layer MoS2

We detect electroluminescence in single layer molybdenum disulfide (MoS2) field-effect transistors built on transparent glass substrates. By comparing the absorption, photoluminescence, and electroluminescence of the same MoS2 layer, we find that they all involve the same excited state at 1.8 eV. The electroluminescence has pronounced threshold behavior and is localized at the contacts. The results show that single layer MoS2, a direct band gap semiconductor, could be promising for novel optoelectronic devices, such as two-dimensional light detectors and emitters.

Graphene field-effect transistors as room-temperature terahertz detectors

The unique optoelectronic properties of graphene make it an ideal platform for a variety of photonic applications, including fast photodetectors, transparent electrodes in displays and photovoltaic modules, optical modulators, plasmonic devices, microcavities, and ultra-fast lasers. Owing to its high carrier mobility, gapless spectrum and frequency-independent absorption, graphene is a very promising material for the development of detectors and modulators operating in the terahertz region of the electromagnetic spectrum (wavelengths in the hundreds of micrometres), still severely lacking in terms of solid-state devices. Here we demonstrate terahertz detectors based on antenna-coupled graphene field-effect transistors. These exploit the nonlinear response to the oscillating radiation field at the gate electrode, with contributions of thermoelectric and photoconductive origin. We demonstrate room temperature operation at 0.3 THz, showing that our devices can already be used in realistic settings, enabling large-area, fast imaging of macroscopic samples.

Role of first pass and delayed enhancement in assessment of segmental functional recovery after acute myocardial infarction

PURPOSE

Assessing myocardial viability is crucial in decision making and prognostic restratification after acute myocardial infarction (MI). A number of noninvasive imaging modalities have been employed in viability identification, but contrast-enhanced magnetic resonance (MR) imaging has been shown to be extremely accurate because of its transmural resolution and precise definition of microvascular obstruction. Our purpose was to assess functional recovery after acute MI, with special focus on the role of infarct transmurality and microvascular obstruction.

MATERIALS AND METHODS

Forty-six consecutive patients with first acute MI, reperfused by primary percutaneous transluminal coronary angioplasty (PTCA) (n=40) or fibrinolysis (n=6), underwent MR imaging within the first week to assess oedema, microvascular obstruction, function and viability and then again after 4-6 months to assess functional recovery and scar.

RESULTS

At first MR examination, postcontrast images were analysed according to three patterns, based on a combination of first-pass and delayed-enhancement data: pattern 1 (normal first pass and late hyperenhancement <50% thickness) identified viable myocardium, whereas pattern 2 (late hyperenhancement >50% thickness, with or without first-pass perfusion defect) and pattern 3 (perfusion defect at first pass and late hypoenhancement) recognised nonviable myocardium, with 93% sensitivity, 75% specificity, 92% positive predictive value and 78% negative predictive value for identifying viable tissue. Furthermore, by dividing pattern 2 into two subpatterns, 2A and 2B, based on absence or presence of microvascular obstruction in >50% transmural infarcts, we were able to better identify the segments without recovery or that were nonviable with a 1.39 relative risk of failed recovery.

CONCLUSIONS

After acute MI, not all infarcts with transmurality >50% can be considered nonviable; microvascular obstruction detected at first pass can help to better stratify these cases.

The shear mode of multilayer graphene

The quest for materials capable of realizing the next generation of electronic and photonic devices continues to fuel research on the electronic, optical and vibrational properties of graphene. Few-layer graphene (FLG) flakes with less than ten layers each show a distinctive band structure. Thus, there is an increasing interest in the physics and applications of FLGs. Raman spectroscopy is one of the most useful and versatile tools to probe graphene samples. Here, we uncover the interlayer shear mode of FLGs, ranging from bilayer graphene (BLG) to bulk graphite, and suggest that the corresponding Raman peak measures the interlayer coupling. This peak scales from ~43 cm(-1) in bulk graphite to ~31 cm(-1) in BLG. Its low energy makes it sensitive to near-Dirac point quasiparticles. Similar shear modes are expected in all layered materials, providing a direct probe of interlayer interactions.

Quantifying defects in graphene via Raman spectroscopy at different excitation energies

We present a Raman study of Ar(+)-bombarded graphene samples with increasing ion doses. This allows us to have a controlled, increasing, amount of defects. We find that the ratio between the D and G peak intensities, for a given defect density, strongly depends on the laser excitation energy. We quantify this effect and present a simple equation for the determination of the point defect density in graphene via Raman spectroscopy for any visible excitation energy. We note that, for all excitations, the D to G intensity ratio reaches a maximum for an interdefect distance ∼3 nm. Thus, a given ratio could correspond to two different defect densities, above or below the maximum. The analysis of the G peak width and its dispersion with excitation energy solves this ambiguity.

A combined approach to investigate the toxicity of an industrial landfill's leachate: chemical analyses, risk assessment and in vitro assays

Solid wastes constitute an important and emerging problem. Landfills are still one of the most common ways to manage waste disposal. The risk assessment of pollutants from landfills is becoming a major environmental issue in Europe, due to the large number of sites and to the importance of groundwater protection. Furthermore, there is lack of knowledge for the environmental, ecotoxicological and toxicological characteristics of most contaminants contained into landfill leacheates. Understanding leachate composition and creating an integrated strategy for risk assessment are currently needed to correctly face the landfill issues and to make projections on the long-term impacts of a landfill, with particular attention to the estimation of possible adverse effects on human health and ecosystem. In the present study, we propose an integrated strategy to evaluate the toxicity of the leachate using chemical analyses, risk assessment guidelines and in vitro assays using the hepatoma HepG2 cells as a model. The approach was applied on a real case study: an industrial waste landfill in northern Italy for which data on the presence of leachate contaminants are available from the last 11 years. Results from our ecological risk models suggest important toxic effects on freshwater fish and small rodents, mainly due to ammonia and inorganic constituents. Our results from in vitro data show an inhibition of cell proliferation by leachate at low doses and cytotoxic effect at high doses after 48 h of exposure.

Effects of kaolin on Ophelimus maskelli (Hymenoptera: Eulophidae) in laboratory and nursery experiments

Although recent research has demonstrated that clays provide satisfactory control of some agricultural insect pests, the effect of clays on gall wasps that damage forest trees has not been previously reported. The aim of the current study is to evaluate the effectiveness of the clay kaolin in the laboratory and in the field in reducing the damage caused by the eulophid Ophelimus maskelli (Ashmead) on seedlings of eucalyptus (Eucalyptus L'Hér.) species. In the laboratory, kaolin + wetting agent significantly reduced the percentage of infested leaves and the number of galls per leaf. In the nursery, gall number per leaf was not correlated with leaf area with kaolin + wetting agent but was related to leaf area for all other treatments (wetting agent alone, imidacloprid, and untreated control). In the nursery, gall number per leaf was lower with kaolin + wetting agent and with imidacloprid than with the other two treatments. Overall, kaolin effectively reduced eulophid infestations, and its effect was more persistent than that of imidacloprid. Although application of kaolin might not be feasible on large forested areas, kaolin could represent a valuable control method in nurseries, where the repeated application with more toxic chemicals can result in high concentrations of residual pesticides in the soil.

CORAL: building up the model for bioconcentration factor and defining it's applicability domain

CORAL (CORrelation And Logic) software can be used to build up the quantitative structure--property/activity relationships (QSPR/QSAR) with optimal descriptors calculated with the simplified molecular input line entry system (SMILES). We used CORAL to evaluate the applicability domain of the QSAR models, taking a model of bioconcentration factor (logBCF) as example. This model's based on a large training set of more than 1000 chemicals. To improve the model is predictivity and reliability on new compounds, we introduced a new function, which uses the Delta(obs) = logBCF(expr)--logBCF(calc) of the predictions on the chemicals in the training set. With this approach, outliers are eliminated from the phase of training. This proved useful and increased the model's predictivity.

Mild ring 17 syndrome shares common phenotypic features irrespective of the chromosomal breakpoints location

Ring 17 syndrome is a rare disorder with clinical features influenced by the presence or deletion of the Miller-Dieker critical region (MDCR). Presence of the MDCR is associated with a mild phenotype, including growth delay (GD), mental retardation (MR), seizures, cafè au lait skin (CALS) spots and minor facial dysmorphisms. Previous studies have been mainly focused on this locus providing poor information about the role of other genes located on the p- and q-arms. Here, we used bacterial artificial chromosome (BAC)/P1 artificial chromosome (PAC) and fosmid clones as fluorescence in situ hybridization (FISH) probes to perform a cyto-molecular analysis of a ring 17 case and found that the breakpoints were close to the telomeric ends. METRNL is the sole gene located on the q-arm terminal end, whereas two open reading frames and the RPH3AL gene are located on the terminal p-arm. To detect possibly unrevealed small deletions involving the transcription units, we used subcloned FISH probes obtained by long-range polymerase chain reaction (PCR), which showed that the investigated regions were preserved. Comparing our findings with other reports, it emerges that different breakpoints, involving (or not) large genomic deletions, present overlapping clinical aspects. In conclusion, our data suggest that a mechanism based on gene expression control besides haploinsufficiency should be considered to explain the common phenotypic features found in the mild ring 17 syndrome.

Making graphene luminescent by oxygen plasma treatment

We show that strong photoluminescence (PL) can be induced in single-layer graphene using an oxygen plasma treatment. The PL is spatially uniform across the flakes and connected to elastic scattering spectra distinctly different from those of gapless pristine graphene. Oxygen plasma can be used to selectively convert the topmost layer when multilayer samples are treated.

[Detection of melanoma relapse: a retrospective study of 100 patients]

BACKGROUND

There is no international consensus on practical methods of monitoring melanoma following surgical removal of a primary tumour. The chief aim of such monitoring is to ensure detection of relapse where early diagnosis is crucial for survival (i.e. in-transit and lymph node metastases amenable to surgical removal) and the emergence of any first recurrence of primary melanoma.

AIM

The aim of our study was to identify the role of various agents and diagnostic tools both in first recurrence of primary melanoma and in clinical relapse of melanoma.

PATIENTS AND METHODS

This was a retrospective study covering all patients with in-transit or regional lymph node metastasis seen between January 2005 and December 2007. The type of recurrence and method of detection were studied.

RESULTS

Ninety-four patients presented recurrence, with 66% of relapses comprising regional lymph node metastasis and 34% consisting of in-transit metastases. Thirty-three percent of cases of recurrence were detected by patients themselves, 21% by our department, 22% by a private dermatologist, 18% by a radiologist and 6% by a general practitioner. Fifty-four percent of recurrences among patients aged under 50 years were self-detected compared to 18% among patients aged over 70 years. A second melanoma was detected in six patients.

DISCUSSION

This study underscores the great importance of self-examination in melanoma follow-up with over one third of recurrences being self-detected by patients. Self-examination was more effective for younger patients, emphasizing the need to increase awareness among older patients. This study also demonstrates the essential part played by dermatologists in terms of regular follow-up of melanoma.

Masked complex chromosome rearrangement in a child thought to have del(8qter) as the sole cytogenetic abnormality

Cytogenetic analyses of constitutional diseases have disclosed several chromosomal rearrangements. At the molecular level, these rearrangements often result in the breakage of genes or alteration of genome architecture. Fluorescence in situ hybridization (FISH) and molecular investigations of a patient showing hypotonia and dysmorphic traits revealed a masked complex chromosome abnormality previously detected by G-banding as a simple 8qter deletion. To characterize the genetic rearrangements panels of bacterial artificial chromosomes (BACs) covering 8q24.22-->qter were constructed, and short tandem repeats (STRs) were used to refine the localization of the breakpoints and to assess the parental origin of the defect. Chromosome 8 displayed the breakpoint at 8q24.22 and an unexpected distal breakpoint at 8q24.23 resulting in unbalanced translocation of a small 8q genomic region on the chromosome 16qter. The study of the 16qter region revealed that the 16q subtelomere was retained and the translocated material of distal 8q was juxtaposed. Moreover, molecular analyses showed that part of the translocated 8qter segment on der(16) was partially duplicated, inverted and that the rearrangement arose in the paternal meiosis. These findings emphasize the complexity of some only apparently simple chromosomal rearrangements and suggest a subtelomeric FISH approach to enhance diagnostic care when a cytogenetic terminal deletion is found.