Maarit Kangas

Cloning of a novel bacteria-binding receptor structurally related to scavenger receptors and expressed in a subset of macrophages.

A novel murine plasma membrane protein has been identified in subpopulations of macrophages. It has an intracellular N-terminal domain, a transmembrane domain, and an extracellular region with a short spacer, an 89 Gly-Xaa-Yaa repeat-containing collagenous domain, and a C-terminal cysteine-rich domain. In situ hybridization and immunohistochemical staining have localized the protein to a subset of macrophages in the marginal zone of the spleen and the medullary cord of lymph nodes. No expression was observed in macrophages of liver or lung. Transfected COS cells synthesized a native trimeric plasma membrane protein that bound labeled bacteria and acetylated LDL, but not yeast or Ficoll. The results suggest that the novel protein is a macrophage-specific membrane receptor with a role in host defense, as it shows postnatal expression in macrophages, which are considered responsible for the binding of bacterial antigens and phagocytosis.

Comparison of low-complexity fall detection algorithms for body attached accelerometers.

The elderly population is growing rapidly. Fall related injuries are a central problem for this population. Elderly people desire to live at home, and thus, new technologies, such as automated fall detectors, are needed to support their independence and security. The aim of this study was to evaluate different low-complexity fall detection algorithms, using triaxial accelerometers attached at the waist, wrist, and head. The fall data were obtained from standardized types of intentional falls (forward, backward, and lateral) in three middle-aged subjects. Data from activities of daily living were used as reference. Three different detection algorithms with increasing complexity were investigated using two or more of the following phases of a fall event: beginning of the fall, falling velocity, fall impact, and posture after the fall. The results indicated that fall detection using a triaxial accelerometer worn at the waist or head is efficient, even with quite simple threshold-based algorithms, with a sensitivity of 97-98% and specificity of 100%. The most sensitive acceleration parameters in these algorithms appeared to be the resultant signal with no high-pass filtering, and the calculated vertical acceleration. In this study, the wrist did not appear to be an applicable site for fall detection. Since a head worn device includes limitations concerning usability and acceptance, a waist worn accelerometer, using an algorithm that recognizes the impact and the posture after the fall, might be optimal for fall detection.

Determination of simple thresholds for accelerometry-based parameters for fall detection

The increasing population of elderly people is mainly living in a home-dwelling environment and needs applications to support their independency and safety. Falls are one of the major health risks that affect the quality of life among older adults. Body attached accelerometers have been used to detect falls. The placement of the accelerometric sensor as well as the fall detection algorithms are still under investigation. The aim of the present pilot study was to determine acceleration thresholds for fall detection, using triaxial accelerometric measurements at the waist, wrist, and head. Intentional falls (forward, backward, and lateral) and activities of daily living (ADL) were performed by two voluntary subjects. The results showed that measurements from the waist and head have potential to distinguish between falls and ADL. Especially, when the simple threshold-based detection was combined with posture detection after the fall, the sensitivity and specificity of fall detection were up to 100 %. On the contrary, the wrist did not appear to be an optimal site for fall detection.

Sensitivity and specificity of fall detection in people aged 40 years and over

About one third of home-dwelling people over 65 years of age fall each year. Falling, and the fear of falling, is one of the major health risks that affects the quality of life among older people, threatening their independent living. In our pilot study, we found that fall detection with a waist-worn triaxial accelerometer is reliable with quite simple detection algorithms. The aim of this study was to validate the data collection of a new fall detector prototype and to define the sensitivity and specificity of different fall detection algorithms with simulated falls from 20 middle-aged (40-65 years old) test subjects. Activities of daily living (ADL) performed by the middle-aged subjects, and also by 21 older people (aged 58-98 years) from a residential care unit, were used as a reference. The results showed that the hardware platform and algorithms used can discriminate various types of falls from ADL with a sensitivity of 97.5% and a specificity of 100%. This suggests that the present concept provides an effective method for automatic fall detection.

Macrophage scavenger receptor MARCO: in vitro and in vivo regulation and involvement in the anti-bacterial host defense.

Abstract Recently, a novel murine member of the scavenger receptor class A family, designated MARCO, has been cloned [4] . Scavenger receptors have a characteristic broad ligand specificity and are able to bind various substances, including bacteria cell surface components. The receptor MARCO is expressed by a distinct subset of macrophages in spleen and lymph nodes. Using a panel of monoclonal antibodies (mAbs) specifically directed against MARCO, we investigated the regulation of this receptor in vitro and in vivo. Stimulation of the mouse macrophage cell line J774.2 in vitro with bacterial lipopolysaccharides (LPS) induces upregulation of MARCO surface expression. In accordance with this observation, in mice suffering from endotoxin shock caused by bacterial infection, expression of MARCO is induced on macrophages in the liver, lung and spleen, which normally do not express this receptor. We found that two of the anti-MARCO mAbs, ED29 and ED31, were able to block ligand binding. They inhibited the uptake of heat-killed Escherichia coli by MARCO expressing CHO cells. Further experiments will be needed to confirm the importance of MARCO in the anti-bacterial host defense.

Comparison of real-life accidental falls in older people with experimental falls in middle-aged test subjects

Falling is a common accident among older people. Automatic fall detectors are one method of improving security. However, in most cases, fall detectors are designed and tested with data from experimental falls in younger people. This study is one of the first to provide fall-related acceleration data obtained from real-life falls. Wireless sensors were used to collect acceleration data during a six-month test period in older people. Data from five events representing forward falls, a sideways fall, a backwards fall, and a fall out of bed were collected and compared with experimental falls performed by middle-aged test subjects. The signals from real-life falls had similar features to those from intentional falls. Real-life forward, sideways and backward falls all showed a pre impact phase and an impact phase that were in keeping with the model that was based on experimental falls. In addition, the fall out of bed had a similar acceleration profile as the experimental falls of the same type. However, there were differences in the parameters that were used for the detection of the fall phases. The beginning of the fall was detected in all of the real-life falls starting from a standing posture, whereas the high pre impact velocity was not. In some real-life falls, multiple impacts suggested protective actions. In conclusion, this study demonstrated similarities between real-life falls of older people and experimental falls of middle-aged subjects. However, some fall characteristics detected from experimental falls were not detectable in acceleration signals from corresponding heterogeneous real-life falls.

Sensitivity and false alarm rate of a fall sensor in long-term fall detection in the elderly

Background: About a third of home-dwelling older people fall each year, and institutionalized older people even report a two- or threefold higher rate for falling. Automatic fall detection systems have been developed to support the independent and secure living of the elderly. Even though good fall detection sensitivity and specificity in laboratory settings have been reported, knowledge about the sensitivity and specificity of these systems in real-life conditions is still lacking. Objective: The aim of this study was to evaluate the long-term fall detection sensitivity and false alarm rate of a fall detection prototype in real-life use. Methods: A total of 15,500 h of real-life data from 16 older people, including both fallers and nonfallers, were monitored using an accelerometry-based sensor system with an implemented fall detection algorithm. Results: The fall detection system detected 12 out of 15 real-life falls, having a sensitivity of 80.0%, with a false alarm rate of 0.049 alarms per usage hour with the implemented real-time system. With minor modification of data analysis the false alarm rate was reduced to 0.025 false alarms per hour, equating to 1 false fall alarm per 40 usage hours. Conclusion: These data suggest that automatic accelerometric fall detection systems might offer a tool for improving safety among older people.

Nordic eHealth Indicators: Organisation of research, first results and plan for the future.

eHealth indicator and benchmarking activities are rapidly increasing nationally and internationally. The work is rarely based on a transparent methodology for indicator definition. This article describes first results of testing an indicator methodology for defining eHealth indicators, which was reported at the Medical Informatics Europe conference in 2012. The core elements of the methodology are illustrated, demonstrating validation of each of them in the context of Nordic eHealth Indicator work. Validation proved the importance of conducting each of the steps of the methodology, with several scientific as well as practical outcomes. The article is based on a report to be published by the Nordic Council of Ministers [4].

Effect of wrist-worn activity monitor feedback on physical activity behavior: A randomized controlled trial in Finnish young men

The purpose of this study is to evaluate whether the use of an activity monitor providing feedback has an effect on physical activity (PA) in young men. A population-based sample of 276 conscription-aged (mean = 17.9, SD = 0.7 years) men participated in a 3-month randomized controlled trial in Oulu in 2012. Participants were randomized to an intervention group (INT, N = 137) and a control group (CON, N = 139). INT received a wrist-worn monitor (Polar Active) showing daily activity, and CON received identical monitors without feedback. Main outcome was the change from baseline in objectively measured weekly time spent in moderate-to-vigorous PA (MVPA) and sedentary activity (SED), as assessed by generalized estimation equations (GEE). Other lifestyle factors were assessed by a questionnaire at baseline and at 3 months. Weekly physical activity data (≥ 4 days with ≥ 8 h each) were obtained from 72 (53%) and 90 (65%) men in the INT and CON, respectively. Based on GEE, time spent in MVPA increased (p = 0.012) and SED decreased (p = 0.032) in the INT compared with the CON. During the first 7 weeks, the INT spent on average 1 h less sedentary than the CON (t-test, p < 0.05). During the first week, the INT showed 12 minutes more MVPA compared to the CON (t-test, p = 0.034). Based on questionnaire data, the proportion of the most sedentary men decreased in the INT (Wilcoxon test, 28% vs. 10%, p = 0.029), with no change in the CON (20% vs. 19%, p = 0.546). To conclude, a wrist-worn activity monitor providing feedback had a short-term positive effect on PA and SED in young men. Trial registration This is a pilot study for a larger randomized controlled trial registered to the clinical trials register NCT01376986.

Nordic eHealth benchmarking

The report presents results of the Nordic eHealth Research Network, a subgroup of the eNordic Council of Ministers Health group. The network defined and collected data for altogether 49 common eHea ...