An Approach to Canonical Correlation Analysis Based on Rényi's Pseudodistances.

Canonical Correlation Analysis (CCA) infers a pairwise linear relationship between two groups of random variables, X and Y. In this paper, we present a new procedure based on Rényi's pseudodistances (RP) aiming to detect linear and non-linear relationships between the two groups. RP canonical analysis (RPCCA) finds canonical coefficient vectors, a and b, by maximizing an RP-based measure. This new family includes the Information Canonical Correlation Analysis (ICCA) as a particular case and extends the method for distances inherently robust against outliers. We provide estimating techniques for RPCCA and show the consistency of the proposed estimated canonical vectors. Further, a permutation test for determining the number of significant pairs of canonical variables is described. The robustness properties of the RPCCA are examined theoretically and empirically through a simulation study, concluding that the RPCCA presents a competitive alternative to ICCA with an added advantage in terms of robustness against outliers and data contamination.

Predictors of Response to Vedolizumab in Patients with Ulcerative Colitis: Results from the Greek VEDO-IBD Cohort.

BACKGROUND: Optimization of treatment with biologics is currently an unmet need for patients with ulcerative colitis (UC). Real-world studies provide neutral estimates of drug efficacy and safety within unselected patient populations and allow for the recognition of specific characteristics that affect response to therapy. AIMS: We aimed to depict the efficacy of vedolizumab in patients with UC in a real-world setting and identify prognosticators of improved outcomes. METHODS: Patients with active UC who commenced treatment with vedolizumab were prospectively followed up. Patient-reported outcomes (PROs) and clinical/endoscopic-reported outcomes were recorded at baseline and at weeks 14 and 54. Predefined endpoints of early and persistent efficacy were analyzed against clinical characteristics to identify prognostic factors for response. RESULTS: We included 96 patients (anti-TNF-exposed = 38.5%). At week 14, 73 patients (76%) had clinical response and 54 (56.3%) clinical remission. At week 54, the primary endpoint of vedolizumab persistence was met by 72 patients (75%), whereas steroid-free clinical remission by 59.4%. Among patients who had endoscopy, rates for mucosal healing (Mayo endoscopic score of 0) were 29.8% at week 14 and 44.6% at week 54, respectively. Vedolizumab treatment led to significant improvements in quality of life. Corticosteroid-refractory or anti-TNF-refractory disease, articular manifestations, and high baseline UC-PRO2 were associated with decreased efficacy of vedolizumab in the primary and secondary outcomes. CONCLUSIONS: Vedolizumab is characterized by high efficacy and long-term treatment persistence in UC. More aggressive disease, as indicated by refractoriness to steroids or anti-TNFs and elevated baseline PROs, may predict suboptimal response and help pre-treatment prognostic stratification of patients.

Non-stenting treatment versus endoscopic stent placement in staple line leaks after laparoscopic sleeve gastrectomy.

PURPOSE: Presentation of results of non-stenting treatment versus endoscopic stenting placement in gastric staple leaks after laparoscopic sleeve gastrectomy (LSG). METHODS: Between January 2007 and August 2020, 1371 eligible patients underwent LSG. After gastric leak detection, patients were classified into treatment groups A (endoscopic stent placement) and B (non-stenting management). Overall hospital stay, the time to complete gastric leak resolution and the incidence of further operative management constituted the main outcome measures. Statistical analysis included descriptive statistics and linear regression tests as needed. RESULTS: A total of 27 patients (19 F/8 M, median age: 44.8 years (range: 36-58) with median preoperative BMI: 43.5 kg/m2 (range: 37.0-48.7)) presented with gastric staple line leak (1.9%) - mean detection day 5.8 postop (range: 1-12). Eight patients enrolled in group A and 19 patients in group B. The mean hospital stay for group A was 41.2 days (range: 24-60) versus 15 days (range: 12-18) for group B (p < 0.001). Complete leakage resolution was observed at mean 42.4 days (range 25-60) for group A and 34.5 days (range: 28-40) for group B patients, (p = 0.025). Only 2 group A patients accomplished complete leak resolution without additional intervention. Five group A patients (62.5%) versus 4 group B patients (21.1%) needed operative intervention during the treatment course (p = 0.037). CONCLUSIONS: Conservative, non-stenting treatment of staple line leaks after LSG is feasible and is associated with superior results in terms of hospital say and leak resolution in comparison to endoscopic stenting.

Epithelioid hemangioendothelioma of the retroperitoneum - a rare vascular tumor.

Epithelioid hemangioendothelioma (EHE) is a rare vascular tumor, affecting the liver, the lungs and the bones most frequently. It has a heterogenous clinical presentation and there is no consensus on optimal treatment. This report aims to present a rare case of a retroperitoneal EHE and to discuss on proper management.

Optimised hyperbolic microchannels for the mechanical characterisation of bio-particles.

The transport of bio-particles in viscous flows exhibits a rich variety of dynamical behaviour, such as morphological transitions, complex orientation dynamics or deformations. Characterising such complex behaviour under well controlled flows is key to understanding the microscopic mechanical properties of biological particles as well as the rheological properties of their suspensions. While generating regions of simple shear flow in microfluidic devices is relatively straightforward, generating straining flows in which the strain rate is maintained constant for a sufficiently long time to observe the objects' morphologic evolution is far from trivial. In this work, we propose an innovative approach based on optimised design of microfluidic converging-diverging channels coupled with a microscope-based tracking method to characterise the dynamic behaviour of individual bio-particles under homogeneous straining flow. The tracking algorithm, combining a motorised stage and a microscopy imaging system controlled by external signals, allows us to follow individual bio-particles transported over long-distances with high-quality images. We demonstrate experimentally the ability of the numerically optimised microchannels to provide linear velocity streamwise gradients along the centreline of the device, allowing for extended consecutive regions of homogeneous elongation and compression. We selected three test cases (DNA, actin filaments and protein aggregates) to highlight the ability of our approach for investigating dynamics of objects with a wide range of sizes, characteristics and behaviours of relevance in the biological world.

How breast cancer treatments affect the quality of life of women with non-metastatic breast cancer one year after surgical treatment: a cross-sectional study in Greece.

BACKGROUND: The continuously increasing survivorship of female breast cancer makes the monitoring and improvement of patients' quality of life ever so important. While globally there is a growing body of research on health-related quality of life 1 year after surgical treatment for non-metastatic breast cancer, up-to-date information regarding Greek patients is scarce. OBJECTIVE: To measure the level of QoL of non-metastatic BC survivors in Greece 1 year after surgery. METHODS: A sample of 200 female breast cancer survivors aged 18 to 75, who followed up as outpatients in five public hospitals were included in this cross-sectional study. All recruited patients agreed to participate in the study (100% response rate). Quality of life data were collected through the EORTC QLQ-C30 as well as BR23 questionnaires. RESULTS: Cronbach's alpha for all scales of the two questionnaires was from 0.551 to 0.936 indicating very good reliability. According to the Multiple Linear Regression, older patients showed a lower future perspective (p = .031), with those living in rural areas, which was associated with more financial difficulties (p = .001). Women with tertiary education and those who had been hospitalized in a university hospital recorded better on global health status (p = .003 and .000 respectively). Patients who underwent chemotherapy reported better scores in the emotional function sub-scale (p = .025). Women with reconstruction and at least one complication appeared to have significantly better scores in future perspective and social function (p = .005, .002 respectively). CONCLUSIONS: Breast cancer survivors were found to have an overall good quality of life, functioning/symptoms scores and were satisfied with the provided care.

Model Selection in a Composite Likelihood Framework Based on Density Power Divergence.

This paper presents a model selection criterion in a composite likelihood framework based on density power divergence measures and in the composite minimum density power divergence estimators, which depends on an tuning parameter α . After introducing such a criterion, some asymptotic properties are established. We present a simulation study and two numerical examples in order to point out the robustness properties of the introduced model selection criterion.

Composite Likelihood Methods Based on Minimum Density Power Divergence Estimator.

In this paper, a robust version of the Wald test statistic for composite likelihood is considered by using the composite minimum density power divergence estimator instead of the composite maximum likelihood estimator. This new family of test statistics will be called Wald-type test statistics. The problem of testing a simple and a composite null hypothesis is considered, and the robustness is studied on the basis of a simulation study. The composite minimum density power divergence estimator is also introduced, and its asymptotic properties are studied.

Alexander the Great (356-323 BC) and His Injury in Kyropolis Reconsidered.

Purpose: To reconsider Alexander the Great's injury in Kyropolis. Methods: Historical sources were compared with modern neurosurgery. Results: Earlier interpretations were focused on the transient blindness Alexander the Great presented after the injury, but according to our point of view we should rather focus on his dysarthria which lasted almost two months. Conclusion: We propose the hypothesis that Alexander the Great developed a posttraumatic delayed cerebellar syndrome after the injury.

Hybrid Repair of a Common Carotid Pseudoaneurysm and Concomitant Internal Carotid Stenosis With Retrograde Stenting and Carotid Endarterectomy.

This report aims to present a rare case of a common carotid artery (CCA) pseudoaneurysm with a concomitant internal carotid artery (ICA) stenosis that were treated with a hybrid technique. This strategy included the retrograde placement of a CCA covered stent under ICA clamping followed by standardized carotid endarterectomy. The technique will be discussed and compared with other possible treatments.

Experimental isolation and preservation of solid organs before transplantation: effects of pretreatment using four different molecules.

OBJECTIVES: In transplantation surgery, the ischaemic organ and reperfusion impairment after cold storage remains a considerable risk factor for impaired function and potential failure of the grafted organ. Substantial logistical efforts have been undertaken to reduce the cold ischaemic time because the demand for available transplant organs and the periods of cold ischaemia are increasing. METHODS: Four molecules were investigated (erythropoietin, sildenafil, lazaroid [U74389G], octreotide) in individual intravenous infusions 1 hour before the organ was harvested. This study was performed in 30 healthy landrace/large-white pigs (male; >10 weeks old; average weight, 22 ± 2 kg) in groups of six. The organs were studied at harvest, and at 8 and 24 hours post-harvest. RESULTS: The lazaroid molecule increased malondialdehyde (MDA) levels in the liver and pancreas at 8 hours. Hepatic lazaroid molecules improved liver histology at 8 and 24 hours. For kidneys, erythropoietin had a positive effect at 24 hours post-harvest. For the pancreas, octreotide showed better performance. In the lungs, there was less interstitial oedema with erythropoietin and lazaroid compared with the control group at 8 hours post-harvest. CONCLUSION: All molecules had a positive effect and decreased ischaemia/reperfusion graft injury. Thus, pretreatment before organ harvest has a beneficial role.

Feasibility of a New Wearable Device to Estimate Acute Stress in Novices During High-fidelity Surgical Simulation.

BACKGROUND: Stress associated with learning of a psychomotor task can influence the trainees learning ability. Surgical simulation is a validated training milieu designed to replicate real-life situations, prevent biases and provide objective metrics. However, the complexity of stress mechanisms and the absence of a reliable detection method make stress estimation difficult to quantify and to interpret. AIM: a) To assess the feasibility of a new watch-sized device to noninvasively measure stress parameters in novices during a simulation task and b) to compare its derived cardiac stress parameters to those of an ambulatory Holter monitor. MATERIALS AND METHODS: Twenty-one novices were trained on a basic skills module. During base line, exercise, and recovery phases, all subjects wore a wearable device and data regarding blood volume pressure, heart rate, inter beat interval, electrodermal activity, and skin temperature were recorded. Additionally, Holter Monitoring was used to concomitantly capture heart rate, R-R intervals and heart rate variability. Before and after each experiment, all subjects completed the short, six-item STAI scale. RESULTS: Data analysis showed: a) when compared to STAI, electrodermal activity exhibited the best correlation, sensitivity and specificity and b) the device derived cardiac parameters highly correlated with the reciprocal Holter values during all experiment phases. CONCLUSION: This wearable device is an easy to use and well accepted by the participants noninvasive tool, which can provide accurate stress estimation in our simulation setting. Additionally, it can replicate Holter derived stress related heart parameters, thus eliminating the need to wear a rather cumbersome device.