A novel approach for discovering human behavior patterns using unsupervised methods.

BACKGROUND: As is well known, elderly people gradually lose the ability of self-care. The decline can be reflected in changes in their daily life behavior. A solution to assess their health status is to design sensor-enhanced living environments to observe their behavior, in which unobtrusive sensors are usually used. With respect to information extraction from the dataset collected by means of these kinds of sensors, unsupervised methods have to be relied on for practical application. Under the assumption that human lifestyle is associated with health status, this study intends to propose a novel approach to discover behavior patterns using unsupervised methods. METHODS: To evaluate the feasibility of this approach it was applied to datasets collected in the GAL-NATARS study. The study is part of the Lower Saxony research network Design of Environments for Aging (GAL) and conducted in subjects' home environments. The subjects recruited in GAL-NATARS study are older people (age ≥ 70 years), who are discharged from hospital to live alone again at their homes after treatment of a femoral fracture. RESULTS: The change of lifestyle regularity is measured. By analyzing the correlation between the extracted information and medical assessment results of four subjects, two of them exhibited impressive association and the other two showed less association. CONCLUSIONS: The approach may provide complementary information for health assessment; however, the dominant relationship between the change of behavior patterns and the health status has to be shown and datasets from more subjects must be collected in future studies. LIMITATIONS: Merely environmental data were used and no wearable sensor for activity detection or vital parameter measurement is taken into account. Therefore, this cannot comprehensively reflect reality.

Home-centered health-enabling technologies and regional health information systems. An integration approach based on international standards.

INTRODUCTION: This article is part of the Focus Theme of Methods of Information in Medicine on "Using Data from Ambient Assisted Living and Smart Homes in Electronic Health Records". OBJECTIVES: In this paper, we present a prototype of a Home-Centered Health-Enabling Technology (HET-HC), which is able to capture, store, merge and process data from various sensor systems at people's home. In addition, we present an architecture designed to integrate HET-HC into an exemplary regional Health Information System (rHIS). METHODS: rHIS are traditionally document-based to fit to the needs in a clinical context. However, HET-HC are producing continuous data streams for which documents might be an inappropriate representation. Therefore, the HET-HC could register placeholder-documents at rHIS. These placeholder-documents are assembled upon user-authenticated request by the HET-HC and are always up-to-date. Moreover, it is not trivial to find a clinical coding system for continuous sensor data and to make the data machine-readable in order to enhance the interoperability of such systems. Therefore, we propose the use of SNOCAP-HET, which is a nomenclature to describe the context of sensor-based measurements in health-enabling technologies. RESULTS: We present an architectural approach to integrate HET-HC into rHIS. Our solution is the centralized registration of placeholder-documents with rHIS and the decentralized data storage at people's home. CONCLUSIONS: We concluded that the presented architecture of integrating HET-HC into rHIS might fit well to the traditional approach of document-based data storage. Data security and privacy issues are also duly considered.

Measurement of accelerometry-based gait parameters in people with and without dementia in the field: a technical feasibility study.

BACKGROUND: Gait analyses are an important tool to diagnose diseases or to measure the rehabilitation process of patients. In this context, sensor-based systems, and especially accelerometers, gain in importance. They are able to improve objectiveness of gait analyses. In clinical settings, there is usually a supervisor who gives instructions to the patients, but this can have an influence on patients' gait. It is expected that this effect will be smaller in field studies. OBJECTIVE: Aim of this study was to capture and evaluate gait parameters measured by a single waist-mounted accelerometer during everyday life of subjects. METHODS: Due to missing ground-truth in unsupervised conditions, another external criterion had to be chosen. Subjects of two different groups were considered: patients with dementia (DEM) and active older people (ACT). These groups were chosen, because of the expected difference in gait. The idea was to quantify the expected difference of accelerometric-based gait parameters. Gait parameters were e.g. velocity, step frequency, compensation movements, and variance of the accelerometric signal. RESULTS: Ten subjects were measured in each group. The number of walking episodes captured was 1,187 (DEM) vs. 1,809 (ACT). The compensation and variance parameters showed an AUC value (Area Under the Curve) between 0.88 and 0.92. In contrast, velocity and step frequency performed poorly (AUC values of 0.51 and 0.55). It was possible to classify both groups using these parameters with an accuracy of 89.2%. CONCLUSION: The results showed a much higher amount of walking episodes in field studies compared to supervised clinical trials. The classification showed a high accuracy in distinguishing between both groups.

Metabolic profiling of oxylipins upon sorbitol treatment in barley leaves.

In barley leaves 13-lipoxygenases (LOXs) are induced by salicylate and jasmonate. Here, we analyse by metabolic profiling the accumulation of oxylipins upon sorbitol treatment. Although 13-LOX-derived products are formed and specifically directed into the reductase branch of the LOX pathway, accumulation is much later than in the cases of salicylate and jasmonate treatment. In addition, under these conditions only the accumulation of jasmonates as additional products of the LOX pathway has been found.

Formation of lipoxygenase-pathway-derived aldehydes in barley leaves upon methyl jasmonate treatment.

In barley leaves, the application of jasmonates leads to dramatic alterations of gene expression. Among the up-regulated gene products lipoxygenases occur abundantly. Here, at least four of them were identified as 13-lipoxygenases exhibiting acidic pH optima between pH 5.0 and 6.5. (13S,9Z,11E,15Z)-13-hydroxy-9,11,15-octadecatrienoic acid was found to be the main endogenous lipoxygenase-derived polyenoic fatty acid derivative indicating 13-lipoxygenase activity in vivo. Moreover, upon methyl jasmonate treatment > 78% of the fatty acid hydroperoxides are metabolized by hydroperoxide lyase activity resulting in the endogenous occurrence of volatile aldehydes. (2E)-4-Hydroxy-2-hexenal, hexanal and (3Z)- plus (2E)-hexenal were identified as 2,4-dinitro-phenylhydrazones using HPLC and identification was confirmed by GC/MS analysis. This is the first proof that (2E)-4-hydroxy-2-hexenal is formed in plants under physiological conditions. Quantification of (2E)-4-hydroxy-2-hexenal, hexanal and hexenals upon methyl jasmonate treatment of barley leaf segments revealed that hexenals were the major aldehydes peaking at 24 h after methyl jasmonate treatment. Their endogenous content increased from 1.6 nmol.g-1 fresh weight to 45 nmol.g-1 fresh weight in methyl-jasmonate-treated leaf segments, whereas (2E)-4-hydroxy-2-hexenal, peaking at 48 h of methyl jasmonate treatment increased from 9 to 15 nmol.g-1 fresh weight. Similar to the hexenals, hexanal reached its maximal amount 24 h after methyl jasmonate treatment, but increased from 0.6 to 3.0 nmol.g-1 fresh weight. In addition to the classical leaf aldehydes, (2E)-4-hydroxy-2-hexenal was detected, thereby raising the question of whether it functions in the degradation of chloroplast membrane constituents, which takes place after methyl jasmonate treatment.

Mechanisms of improved physical performance of chronic hemodialysis patients after erythropoietin treatment.

Correction of the anemia that is common among chronic hemodialysis patients by treatment with human recombinant erythropoietin (rHuEPO), even if incomplete, improves physical performance of patients. Oxygen uptake and physical work capacity at maximal work loads and at the anaerobic threshold increase by approximately 20%. Analysis of underlying mechanisms by pulmonary function tests and ergospirometry demonstrate that improved oxygen transport in the blood and its concomitant changes of the anaerobic threshold and heart rate appear to be main causes of improvement. Parameters of respiratory mechanics and gas exchange remain essentially unaltered.

Amphetamine and methamphetamine determination in urine by reversed-phase high-performance liquid chromatography with simultaneous sample clean-up and derivatization with 1,2-naphthoquinone 4-sulphonate on solid-phase cartridges.

A liquid-solid procedure is proposed for sample clean-up and derivatization of amphetamine and methamphetamine in urine samples. The reagent was 1,2-naphthoquinone 4-sulphonate, and a commercial C18 packing cartridge was used. The samples derivatized at room temperature were chromatographed on a 5-microns Hypersil ODS (250 x 4 mm I.D.) with an elution gradient of acetonitrile-water containing propylamine. Under these conditions, the amines were eluted with short retention times. The procedure was used to determine amphetamine, or methamphetamine with its metabolite amphetamine, in spiked urine samples. The detection limit (at a signal-to-noise ratio of 3) for amphetamine (0.1 microgram/ml) was similar to that obtained with liquid-liquid derivatization and to those obtained with immobilized reagents on a polymeric solid support. The detection limit for methamphetamine (0.4 microgram/ml) was higher than with the liquid-liquid procedure because of the lower reactivity on the cartridge. The precision and accuracy of the method were also studied.

Chlamydia trachomatis infection during pregnancy: can it cause an intrauterine infection?

In an attempt to prove the presence of intrauterine fetal chlamydial infection, sera from 26 laboring women, who tested positive for cervical chlamydial antigen in the first half of their pregnancies, and from 43 laboring women with no evidence of such infection, and sera from the cord of their delivered infants were tested for chlamydial IgA-, IgG- and IgM-specific antibodies. Nine (34.6%) of the 26 women with positive cervical infection and 5 (11.6%) of the 43 women with no identifiable cervical infection had significant antibody levels at the time of the delivery. Three of the 26 (11.5%) babies born to the mothers with positive cervical chlamydial infection early in the pregnancy and high antibody titer at delivery were found to have anti-chlamydial antibodies in their cord serum, indicating intrauterine infection; cord sera from the other 43 babies were negative for these antibodies. These findings suggest a low but possible risk of intrauterine infection in the presence of lower genital infection during pregnancy.