Preparing the upper gastrointestinal tract for an esophagogastroduodenoscopy to identify the source of acute bleeding

Esophagogastroduodenoscopy (EGDS) is the main way to diagnose bleeding from the upper gastrointestinal tract. Diagnostic accuracy of the study depends on the preparation. Aim of the study was to evaluate the preparation of the upper parts of the digestive tract in case of esophagogastroduodenal bleeding. Material and methods. The retrospective analysis of 2570 case histories was carried out. Gastric lavage through nasogastric tube was carried out in the main group (1299 patients). Preparation for the primary EGDS was not carried out in the control group (1271 patients). A comparison of the number of EGDS performed and the detection of the bleeding source in the control and the main groups as well as the period of investigation up to the detection of the bleeding source were performed. Results. EGDS without preparation of the upper gastrointestinal tract in case of acute bleeding and determination of the diagnosis is possible in 85,6 % of patients. Preparation of the upper gastrointestinal tract for EGDS prolongs the study period by 30–60 minutes, but allows establishing the diagnosis in 93.7 % of cases that is by 8.1 % more than without preparation

Modern management of acute non-variceal upper gastrointestinal bleeding

Acute, non-varicose bleeding from the upper gastrointestinal tract remains a common clinical problem. Bleeding episodes are associated with high mortality and a significant economic burden on the health care system. Despite the continuing improvement in endoscopic treatment, recurrent bleeding and associated mortality are still a pressing issue. In addition to the well-established modalities of endoscopic hemostasis: injection, thermal, mechanical, used both as mono therapy and as part of a combination therapy, the review discusses the use of novel types of endoscopic devices. The results of the use of over-the-scope clips, coagrasper, hemostatic sprays, endoscopic angiography, radiofrequency ablation, cryotherapy and endoscopic suturing device are described. The technical aspects of their application, the issues of efficacy and safety, the advantages and limitations of methods for achieving final endoscopic hemostasis are considered. The methods of initial assessment and treatment strategies for recurrent bleeding and unsuccessful endoscopic hemostasis were also analyzed. Material and methods. Literature search was carried out using the following electronic information resources: CyberLeninka, PubMed, Nature Pathology, MEDLINE, PLoS ONE. Results. Сombined endoscopic hemostasis is a standard therapy in the treatment of gastrointestinal tract cerebral infections with an efficiency of 95-98 %, new modalities of endoscopic hemostasis are able, in some cases, to achieve final endoscopic hemostasis both in primary endoscopic treatment and in recurrent bleeding

Quantifying Privacy: A Novel Entropy-Based Measure of Disclosure Risk

It is well recognised that data mining and statistical analysis pose a serious treat to privacy. This is true for financial, medical, criminal and marketing research. Numerous techniques have been proposed to protect privacy, including restriction and data modification. Recently proposed privacy models such as differential privacy and k-anonymity received a lot of attention and for the latter there are now several improvements of the original scheme, each removing some security shortcomings of the previous one. However, the challenge lies in evaluating and comparing privacy provided by various techniques. In this paper we propose a novel entropy based security measure that can be applied to any generalisation, restriction or data modification technique. We use our measure to empirically evaluate and compare a few popular methods, namely query restriction, sampling and noise addition.Comment: 20 pages, 4 figure

Novel iterative min-max clustering to minimize information loss in statistical disclosure control

In recent years, there has been an alarming increase of online identity theft and attacks using personally identifiable information. The goal of privacy preservation is to de-associate individuals from sensitive or microdata information. Microaggregation techniques seeks to protect microdata in such a way that can be published and mined without providing any private information that can be linked to specific individuals. Microaggregation works by partitioning the microdata into groups of at least k records and then replacing the records in each group with the centroid of the group. An optimal microaggregation method must minimize the information loss resulting from this replacement process. The challenge is how to minimize the information loss during the microaggregation process. This paper presents a new microaggregation technique for Statistical Disclosure Control (SDC). It consists of two stages. In the first stage, the algorithm sorts all the records in the data set in a particular way to ensure that during microaggregation very dissimilar observations are never entered into the same cluster. In the second stage an optimal microaggregation method is used to create k-anonymous clusters while minimizing the information loss. It works by taking the sorted data and simultaneously creating two distant clusters using the two extreme sorted values as seeds for the clusters. The performance of the proposed technique is compared against the most recent microaggregation methods. Experimental results using benchmark datasets show that the proposed algorithm has the lowest information loss compared with a basket of techniques in the literature

A framework for evaluating the utility of data altered to protect confidentiality

When releasing data to the public, statistical agencies and survey organizations typically alter data values in order to protect the confidentiality of survey respondents ’ identities and attribute values. To select among the wide variety of data alteration methods, agencies require tools for evaluating the utility of proposed data releases. Such utility measures can be combined with disclosure risk measures to gauge risk-utility tradeoffs of competing methods. In this paper, we present utility measures focused on differences in inferences obtained from the altered data and corresponding inferences obtained from the original data. Using both genuine and simulated data, we show how the measures can be used in a decision-theoretic formulation for evaluating disclosure limitation procedures

Phase alignment of low-frequency neural activity to the amplitude envelope of speech reflects evoked responses to acoustic edges, not oscillatory entrainment

The amplitude envelope of speech is crucial for accurate comprehension. Considered a key stage in speech processing, the phase of neural activity in the theta-delta bands (1 - 10 Hz) tracks the phase of the speech amplitude envelope during listening. However, the mechanisms underlying this envelope representation have been heavily debated. A dominant model posits that envelope tracking reflects entrainment of endogenous low-frequency oscillations to the speech envelope. Alternatively, envelope tracking reflects a series of evoked responses to acoustic landmarks within the envelope. It has proven challenging to distinguish these two mechanisms. To address this, we recorded magnetoencephalography while participants listened to natural speech, and compared the neural phase patterns to the predictions of two computational models: An oscillatory entrainment model and a model of evoked responses to peaks in the rate of envelope change. Critically, we also presented speech at slowed rates, where the spectrotemporal predictions of the two models diverge. Our analyses revealed transient theta phase-locking in regular speech, as predicted by both models. However, for slow speech we found transient theta and delta phase-locking, a pattern that was fully compatible with the evoked response model but could not be explained by the oscillatory entrainment model. Furthermore, encoding of acoustic edge magnitudes was invariant to contextual speech rate, demonstrating speech rate normalization of acoustic edge representations. Taken together, our results suggest that neural phase locking to the speech envelope is more likely to reflect discrete representation of transient information rather than oscillatory entrainment