Neutrophil-to-lymphocyte ratio as a prognostic factor for pharyngocutaneous fistula after total laryngectomy.

SUMMARY: The role of systemic inflammatory response as a prognostic factor has been proposed in a variety of cancers. The purpose of this study was to investigate the prognostic value of the pretreatment neutrophil-to-lymphocyte ratio (NLR) in the incidence of pharyngocutaneous fistula (PCF) in patients who underwent total laryngectomy. We conducted a retrospective cohort analysis of 141 patients with squamous cell carcinoma of larynx who underwent total laryngectomy from 2009 to 2015. The incidence of PCF was 49.6%. A higher risk of 23% was observed among patients with NLR > 2.5 for the occurrence of PCF (p = 0.007). Patients with laryngeal squamous cell carcinoma who present elevated values in the ration > LR> (> 2.5) presented a higher risk of developing pharyngocutaneous fistula in the postoperative setting of total laryngectomy.

Bimetallic PdAg nanoparticle arrays from monolayer films of diblock copolymer micelles.

The self-assembly technique provides a highly efficient route to generate well-ordered structures on a nanometer scale. In this paper, well-ordered arrays of PdAg alloy nanoparticles on flat substrates with narrow distributions of particle size (6-7 nm) and interparticle spacing (about 60 nm) were synthesized by the block copolymer micelle approach. A home-made PS-b-P4VP diblock copolymer was prepared to obtain a micellar structure in toluene. Pd and Ag salts were then successfully loaded in the micellar core of the PS-b-P4VP copolymer. A self-assembled monolayer of the loaded micelles was obtained by dipping the flat substrate in the solution. At this stage, the core of the micelles was still loaded with the metal precursor rather than with a metal. Physical and chemical reducing methods were used to reduce the metal salts embedded in the P4VP core into PdAg nanoparticles. HRTEM and EDX indicated that Pd-rich PdAg alloy nanoparticles were synthesized by chemical or physical reduction; UV-visible spectroscopy observations confirmed that metallic PdAg nanoparticles were quickly formed after chemical reduction; XPS measurements revealed that the PdAg alloy nanoparticles were in a metallic state after a short time of exposure to O2 plasma and after hydrazine reduction.

Stapler suture of the pharynx after total laryngectomy.

The use of a stapler for pharyngeal closure during total laryngectomy was first described in 1971. It provides rapid watertight closure without surgical field contamination. The objective of our study was to compare the incidence of pharyngocutaneous fistula after total laryngectomy with manual and mechanical closures of the pharynx. This was a non-randomised, prospective clinical study conducted at two tertiary medical centres from 1996 to 2011 including consecutive patients with laryngeal tumours who underwent total laryngectomy. We compared the incidence of pharyngocutaneous fistula between two groups of patients: in 20 patients, 75 mm linear stapler closure was applied, whereas in 67 patients a manual suture was used. Clinical data were compared between groups. The groups were statistically similar in terms of gender, age, diabetes mellitus, smoking and alcohol consumption and tumour site. The group of patients who underwent stapler-assisted pharyngeal closure had a higher number of patients with previous tracheotomy (p < 0.001) and previous chemoradiation (p < 0.001). The incidence of pharyngocutaneous fistula was 30% in the mechanical closure group and 20.9% in the manual suture group (p = 0.42). In conclusion the use of the stapler does not increase the rate of fistulae.

PP008. Lipotoxicity and preeclampsia: A probable correlation (preliminary results).

INTRODUCTION: The impact of preeclampsia (PE) of pregnancy is seen as a global concern. Despite their importance, PE does not have well-established causes. Several studies point to obesity as a predisposing factor for PE [1]. In a systematic review Duckitt and Harrington showed that in women with BMI⩾30 the relative risk of developing PE is equal to 2.1 [2]. Bianco et al. demonstrated that the chance of patients with BMI⩾35 developing PE is more than 4 times [3]. Furthermore, it is believed that the intracellular accumulation of triglycerides cause mitochondrial dysfunction, more electron transport and generation of ROS (Reactive Oxygen Species) [4], causing a harmful effect on the endothelium. OBJECTIVES: To compare the incidence of potential lipotoxicity markers among normal pregnant women and with pre-eclampsia. METHODS: A case-control study, including pregnant women from October 2011 to January 2012 at Hospital Guilherme Álvaro in Santos/Brazil. The study group consisted of 27 mothers with pre-eclampsia, according to the criteria of NHBPEP (2000) and the control group consisted of 27 mothers with normal pregnancy, who gave birth vaginally, at term without hypertension. The exclusion criteria were diagnosis of collagen diseases, smoking, diabetes, twin pregnancy and fetal malformations. Blood samples were collected immediately after delivery and the results were analyzed in conjunction with maternal data, according to the following variables: age, body mass index (BMI), serum cholesterol total and fractions, glucose, triglyceride and creative protein. Analysis of SF data was performed by calculating the odds ratio adopting an hypothesis rejection level of 0.05. RESULTS: The PE group had BMI>30 (or), serum triglycerides>150 (or) and LDL cholesterol>100 (or) more frequently than normal mothers, and as regards statistical significance comparing the age of the women, glucose level, HDS cholesterol, there was no significant difference between the groups. CONCLUSION: In pregnancy, lipotoxicity reduces the ability of trophoblastic invasion, causing maternal systemic endothelial and placental dysfunction causing alterations in metabolic functions. All such changes maintain a close relationship with the pathophysiology of PE. Monitoring pregestational period of obese patients or those with lipid disorders is part of the medical arsenal against PE by monitoring and advising on the best time to conceive.

PP044. Profile of pregnant women with pre-eclampsia treated in priority area.

INTRODUCTION: The maternity mortality rate in the Santos lowlands region, priority region of São Paulo/Brazil, is higher when compared to regions in the state of São Paulo. The hypertensive disorders are implicated in approximately 20% of death. Severe preeclampsia (PE) is recognized as the frequent diagnosis associated with maternal and fetal ominous outcomes. The recognition of potential risk support antenatal intervention which could anticipate the installation of catastrophic results. Identifying the epidemiological profile of women who may present with this evolution can guide public health policies and actions of the professionals involved in caring for these women avoiding preformed concepts and contributing to the recognition of local reality situation. OBJECTIVES: Identify the epidemiological profile of women affected by severe PE. METHODS: A descriptive study involving 46 pregnant women admitted to specialized hospital for high-risk pregnancy with the diagnosis of severe PE according to the criteria of NHBPEP (2000), as: blood pressure ⩾160/110mmHg, proteinuria 2.0g/24h or +2 dipstick, serum creatinine >1.2mg/dl (new onset), platelets <100,000/mm(3), microangiopathic hemolysis (increased lactate dehydrogenase), elevated alanine aminotransferase or aspartate aminotransferase, persistent headaches or other cerebral or visual disturbance, persistent epigastric pain or eclampsia in the period from January/2008 to November/2010. RESULTS: The average age of the pregnant women was 25.5years (±6.5), 11 women were multiparous and nulliparous and 35 (76.1%), the average gestational age at admission was 34 4/7, developing to eclampsia and/or HELLP syndrome were 07 women (15.2%), admission often occurred before the installation of labor in (93.5%) had a previous diagnosis of chronic hypertension (30.4%) and in all cases magnesium sulfate administration with an average length of 32h (±16.6h). CONCLUSION: The occurrence of severe PE was more common in nulliparous women at the age of 25years, admitted in prematurity and not in preterm labor. The outcome of seizure and/or HELLP has a considerable impact. The association of chronic hypertension with severe PE is more than 1/4 of the cases. These data are equivalent to other areas of Brazil and may contribute to emphasize the practice of prenatal acting that can recognize and pre-comment possible adverse developments and attitudes aimed at intercepting the process.

Neural network uncertainty assessment using Bayesian statistics: a remote sensing application.

Neural network (NN) techniques have proved successful for many regression problems, in particular for remote sensing; however, uncertainty estimates are rarely provided. In this article, a Bayesian technique to evaluate uncertainties of the NN parameters (i.e., synaptic weights) is first presented. In contrast to more traditional approaches based on point estimation of the NN weights, we assess uncertainties on such estimates to monitor the robustness of the NN model. These theoretical developments are illustrated by applying them to the problem of retrieving surface skin temperature, microwave surface emissivities, and integrated water vapor content from a combined analysis of satellite microwave and infrared observations over land. The weight uncertainty estimates are then used to compute analytically the uncertainties in the network outputs (i.e., error bars and correlation structure of these errors). Such quantities are very important for evaluating any application of an NN model. The uncertainties on the NN Jacobians are then considered in the third part of this article. Used for regression fitting, NN models can be used effectively to represent highly nonlinear, multivariate functions. In this situation, most emphasis is put on estimating the output errors, but almost no attention has been given to errors associated with the internal structure of the regression model. The complex structure of dependency inside the NN is the essence of the model, and assessing its quality, coherency, and physical character makes all the difference between a blackbox model with small output errors and a reliable, robust, and physically coherent model. Such dependency structures are described to the first order by the NN Jacobians: they indicate the sensitivity of one output with respect to the inputs of the model for given input data. We use a Monte Carlo integration procedure to estimate the robustness of the NN Jacobians. A regularization strategy based on principal component analysis is proposed to suppress the multicollinearities in order to make these Jacobians robust and physically meaningful.

Primary progressive aphasia: analisys of 16 cases.

Primary progressive aphasia (PPA) is an intriguing syndrome, showing some peculiar aspects that differentiate it from classical aphasic pictures caused by focal cerebral lesions or dementia. The slow and progressive deterioration of language occurring in these cases provides an interesting model to better understand the mechanisms involved in the linguistic process. We describe clinical and neuroimaging aspects found in 16 cases of PPA. Our patients underwent language and neuropsychological evaluation, magnetic resonance imaging (MRI) and single photon emission computerized tomography (SPECT). We observed a clear distinction in oral expression patterns; patients were classified as fluent and nonfluent. Anomia was the earliest and most evident symptom in both groups. Neuroimaging pointed to SPECT as a valuable instrument in guiding the differential diagnosis, as well as in making useful clinical and anatomical correlations. This report and a comparison to literature are an attempt to contribute to a better understanding of PPA.

Blind source separation in the presence of weak sources.

We investigate the information processing of a linear mixture of independent sources of different magnitudes. In particular we consider the case where a number m of the sources can be considered as "strong" as compared to the other ones, the "weak" sources. We find that it is preferable to perform blind source separation in the space spanned by the strong sources, and that this can be easily done by first projecting the signal onto the m largest principal components. We illustrate the analytical results with numerical simulations.

The "weight smoothing" regularization of MLP for Jacobian stabilization.

In an approximation problem with a neural network, a low-output root mean square (rms) error is not always a universal criterion. In this paper, we investigate problems where the Jacobians--first derivative of an output value with respect to an input value--of the approximation model are needed and propose to add a quality criterion on these Jacobians during the learning step. More specifically, we focus here on the approximation of functionals A; from a space of continuous functions (discretized in pratice) to a scalar space. In this case, the approximation is confronted with the compensation phenomenon: a lower contribution of one input can be compensated by a larger one of its neighboring inputs. In this case, profiles (with respect to the input index) of neural Jacobians are very irregular instead of smooth. Then, the approximation of A becomes an ill-posed problem because many solutions can be chosen by the learning process. We propose to introduce the smoothness of Jacobian profiles as an a priori information via a regularization technique and develop a new and efficient learning algorithm, called "weight smoothing." We assess the robustness of the weight smoothing algorithm by testing it on a real and complex problem stemming from meteorology: the neural approximation of the forward model of radiative transfer equation in the atmosphere. The stabilized Jacobians of this model are then used in an inversion process to illustrate the improvement of the Jacobians after weight smoothing.

Microscopy in solid state science.

The Microstructural Physics group at the Cavendish Laboratory is actively involved in a considerable number of research projects which cover a broad range of materials science. In this paper, we describe briefly several such projects, with particular emphasis given to the application of parallel-detection electron energy loss spectroscopy (PEELS) on a scanning transmission electron microscope (STEM) to the analysis of materials such as stainless steels, catalysts, and high temperature superconductors. In addition, we describe a number of related projects that are currently being carried out in the group, particularly those which utilise and develop novel STEM imaging and analytical techniques.