Development and validation of a gene expression test to identify hard-to-heal chronic venous leg ulcers

Background

Chronic venous leg ulcers pose a significant burden to healthcare systems, and predicting wound healing is challenging. The aim of this study was to develop a genetic test to evaluate the propensity of a chronic ulcer to heal.

Methods

Sequential refinement and testing of a gene expression signature was conducted using three distinct cohorts of human wound tissue. The expression of candidate genes was screened using a cohort of acute and chronic wound tissue and normal skin with quantitative transcript analysis. Genes showing significant expression differences were combined and examined, using receiver operating characteristic (ROC) curve analysis, in a controlled prospective study of patients with venous leg ulcers. A refined gene signature was evaluated using a prospective, blinded study of consecutive patients with venous ulcers.

Results

The initial gene signature, comprising 25 genes, could identify the outcome (healing versus non-healing) of chronic venous leg ulcers (area under the curve (AUC) 0·84, 95 per cent c.i. 0·73 to 0·94). Subsequent refinement resulted in a final 14-gene signature (WD14), which performed equally well (AUC 0·88, 0·80 to 0·97). When examined in a prospective blinded study, the WD14 signature could also identify wounds likely to demonstrate signs of healing (AUC 0·73, 0·62 to 0·84).

Conclusion

A gene signature can identify people with chronic venous leg ulcers that are unlikely to heal.

The U(n) Gelfand-Zeitlin system as a tropical limit of Ginzburg-Weinstein diffeomorphisms

In this paper, we show that the Ginzburg-Weinstein diffeomorphism [Formula: see text] of Alekseev & Meinrenken (Alekseev, Meinrenken 2007 J. Differential Geom.76, 1-34. (10.4310/jdg/1180135664)) admits a scaling tropical limit on an open dense subset of [Formula: see text] The target of the limit map is a product [Formula: see text], where [Formula: see text] is the interior of a cone, T is a torus, and [Formula: see text] carries an integrable system with natural action-angle coordinates. The pull-back of these coordinates to [Formula: see text] recovers the Gelfand-Zeitlin integrable system of Guillemin & Sternberg (Guillemin, Sternberg 1983 J. Funct. Anal.52, 106-128. (10.1016/0022-1236(83)90092-7)). As a by-product of our proof, we show that the Lagrangian tori of the Flaschka-Ratiu integrable system on the set of upper triangular matrices meet the set of totally positive matrices for sufficiently large action coordinates.This article is part of the theme issue 'Finite dimensional integrable systems: new trends and methods'.

A High-Resolution Imaging Technique using a Whole-body, Research Photon Counting Detector CT System

A high-resolution (HR) data collection mode has been introduced to the whole-body, research photon-counting-detector CT system installed in our laboratory. In this mode, 64 rows of 0.45 mm × 0.45 mm detectors pixels were used, which corresponded to a pixel size of 0.225 mm × 0.225 mm at the iso-center. Spatial resolution of this HR mode was quantified by measuring the MTF from a scan of a 50 micron wire phantom. An anthropomorphic lung phantom, cadaveric swine lung, temporal bone and heart specimens were scanned using the HR mode, and image quality was subjectively assessed by two experienced radiologists. Comparison of the HR mode images against their energy integrating system (EID) equivalents using comb filters was also performed. High spatial resolution of the HR mode was evidenced by the MTF measurement, with 15 lp/cm and 20 lp/cm at 10% and 2% MTF. Images from anthropomorphic phantom and cadaveric specimens showed clear delineation of small structures, such as lung vessels, lung nodules, temporal bone structures, and coronary arteries. Temporal bone images showed critical anatomy (i.e. stapes superstructure) that was clearly visible in the PCD system but hardly visible with the EID system. These results demonstrated the potential application of this imaging mode in lung, temporal bone, and vascular imaging. Other clinical applications that require high spatial resolution, such as musculoskeletal imaging, may also benefit from this high resolution mode.

Total artificial heart in the pediatric patient with biventricular heart failure

Mechanical circulatory support emerged for the pediatric population in the late 1980s as a bridge to cardiac transplantation. The Total Artificial Heart (TAH-t) (SynCardia Systems Inc., Tuscon, AZ) has been approved for compassionate use by the Food and Drug Administration for patients with end-stage biventricular heart failure as a bridge to heart transplantation since 1985 and has had FDA approval since 2004. However, of the 1,061 patients placed on the TAH-t, only 21 (2%) were under the age 18. SynCardia Systems, Inc. recommends a minimum patient body surface area (BSA) of 1.7 m(2), thus, limiting pediatric application of this device. This unique case report shares this pediatric institution's first experience with the TAH-t. A 14-year-old male was admitted with dilated cardiomyopathy and severe biventricular heart failure. The patient rapidly decompensated, requiring extracorporeal life support. An echocardiogram revealed severe biventricular dysfunction and diffuse clot formation in the left ventricle and outflow tract. The decision was made to transition to biventricular assist device. The biventricular failure and clot formation helped guide the team to the TAH-t, in spite of a BSA (1.5 m(2)) below the recommendation of 1.7 m(2). A computed tomography (CT) scan of the thorax, in conjunction with a novel three-dimensional (3D) modeling system and team, assisted in determining appropriate fit. Chest CT and 3D modeling following implantation were utilized to determine all major vascular structures were unobstructed and the bronchi were open. The virtual 3D model confirmed appropriate device fit with no evidence of compression to the left pulmonary veins. The postoperative course was complicated by a left lung opacification. The left lung anomalies proved to be atelectasis and improved with aggressive recruitment maneuvers. The patient was supported for 11 days prior to transplantation. Chest CT and 3D modeling were crucial in assessing whether the device would fit, as well as postoperative complications in this smaller pediatric patient.

Abstract P6-07-41: Sub classification of early stage hormone positive (HP) Her-2 negative breast cancer (BC) by immunohistochemistry (IHC) into intrinsic subtypes (IS) and their correlation with Oncotype Recurrence Score (RS)

Background: Early stage HPBC is a heterogenous disease and various models of prognostication are available. Molecular profiling by IS i.e. Luminal A (LA) and Luminal B (LB) is one such attempt but is complex and expensive. Literature suggests a Ki-67 index of ≥14% as a cutoff between LA and LB tumors. LB subtype is associated with worse breast cancer outcomes. Oncotype RS is one of the most robust tools to assess prognosis and predict benefit from chemotherapy in HP Her-2 negative early BC. We sought to investigate the correlation between IHC classification of IS and RS. In addition, we also evaluated incidence of basal immunophenotype in this population.

Methods: Early Stage Her-2 negative HPBC cases that had RS testing from 2007–2011 were found through our database. IHC for Ki-67, CK 5/6 and EGFR was performed if adequate tissue blocks were present. IHC classification of IS was as follows: Ki-67 ≥ 14%: LB; Ki-67 < 14%: LA; CK 5/6 and/or EGFR expression: Basal. An exploratory analysis using Ki-67 cutoff of 19% i.e. LA (<19%); LB (≥19%) was performed to evaluate its effect on correlation with RS.

Results: We found 115 patients. Median age: 62 years. Stage 1: 79/115 (69%) Stage 2: 36/115 (31%). Using Ki-67 cutoff of 14%, LA: 42/115 (36.5%); LB: 72/115 (62.6%); Using Ki-67 cutoff of 19%, LA: 66/115 (57.4%); LB: 48/115 (41.7%); Basal: 1/115(0.9%). Characteristics of LA and LB and their comparison with Oncotype Dx are shown in the Table 1. Compared to LA, LB patients were younger (p = 0.004) and had higher oncotype scores (p = 0.007). However, range of RS in both subtypes was large. Among LB patients, 43% fell in low risk category and only 15% fell into high risk category. Among LA, results seemed to correlate more with expectations; 69% were in low risk category while 5% were in high risk category. When a cutoff of Ki-67 </≥19% was used to classify LA/LB, 42% of LB were still in low risk category of Oncotype Dx. Only 1 patient had basal immunophenotype (Ki-67 25%, RS 42).