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PubMed2006

Mobile peer-to-grid architecture for paramedical emergency operations.

In this paper we describe a distributed architecture that could be used to link emergency medical centres, hospitals, telephone operators, and ambulances into a hybrid Peer-to-Peer (P2P) and Grid system for the sharing of information and transport of data. Distributed computing techniques can be used to connect static and mobile systems, bringing the different tools, expertise and databases together to aggregate patient data "on-the-fly" and then integrate it into a situation and context-specific patient-centred virtual environment. The scenario presented in this paper encapsulates connecting mobile tools and medical devices from ambulances, enabling data transfer to medical centres, and aggregating patient data from numerous sources. The proposed P2G (Peer-to-Grid) framework consolidates Peer-to-Peer and Grid computing research by addressing the mobility of transiently connected devices while supporting interactive configurability of components for dynamic data-driven distributed paramedical scenarios.

Allied Health Personnel↗

PubMed1981

A simple test for the aggregation of disease occurrence in genealogical data.

A simple test for the aggregation of occurrence of a trait in genealogical data is given; a test criterion is developed, and the power of the test to detect aggregation of risk is computed. The test utilizes pairs of individuals between whom transmission of risk factors may occur. As long as aggregation is reasonably strong and prevalence not too low, only modest amounts of data are required. It provides an easy and inexpensive first examination of data which can reveal whether the effort required to conduct more elaborate genealogical studies and analysis is warranted.

Genetic Diseases, Inborn↗

PubMed2002

Temporal stability of psychophysiological response patterns: concepts and statistical tools.

The specificity or patterning of psychophysiological responses to behavioral stimuli is of importance for basic and applied psychophysiological research. However, the statistical tools used to describe specificity are heterogenious and the attempts to describe temporal stability or reliability of such response profiles are even more complicated. The aim of this paper is to present an approach designed to clarify the relationships between different measures of temporal stability of specificity. This is done with a compilation of statistical measures based on variance components. This approach incorporates features of response specificity and reliability. Individual, situational and motivational response specificity are defined in a uniform way with respect to temporal stability. The use of the formulae is demonstrated with an empirical example. As is found in the research on single parameters, the profile reliability of level scores is higher than that of change scores. Furthermore, the stability of individual response patterns is dependent upon the question of whether the data is aggregated across situations or not. Situational response patterns are stable when the data is aggregated across subjects, whereas the stability is low without such aggregation. Issues of inconsistencies of variance estimates are addressed, and the relationships between temporal stability, consistency and covariation of physiological variables are discussed.

Algorithms↗

PubMed2001

Toward best practice: leveraging the electronic patient record as a clinical data warehouse.

Automating clinical and administrative processes via an electronic patient record (EPR) gives clinicians the point-of-care tools they need to deliver better patient care. However, to improve clinical practice as a whole and then evaluate it, healthcare must go beyond basic automation and convert EPR data into aggregated, multidimensional information. Unfortunately, few EPR systems have the established, powerful analytical clinical data warehouses (CDWs) required for this conversion. This article describes how an organization can support best practice by leveraging a CDW that is fully integrated into its EPR and clinical decision support (CDS) system. The article (1) discusses the requirements for comprehensive CDS, including on-line analytical processing (OLAP) of data at both transactional and aggregate levels, (2) suggests that the transactional data acquired by an OLTP EPR system must be remodeled to support retrospective, population-based, aggregate analysis of those data, and (3) concludes that this aggregate analysis is best provided by a separate CDW system.

Benchmarking↗

PubMed2005

Use of the scan statistic on disaggregated province-based data: foot-and-mouth disease in Iran.

The spatial scan statistic was applied to density-smoothed data that approximated the spatial distribution within the area and reduced the potential bias produced when location data have been aggregated for large areas. The method is illustrated, using data on the location of foot-and-mouth disease (FMD) outbreaks in Iran. Data examined were 4477 FMD outbreaks reported on a per province basis between June 1996 and September 2003. A kernel density of the outbreak locations was estimated, using a fixed radius and the centroid of each province as the designated location of all cases reported for the province. The radius that produced a density map with the highest correlation with expert opinion was 4 degrees (latitude/longitude). Livestock density was used as a proxy for the underlying population at risk of acquiring FMD. Livestock and outbreak density maps were overlain to obtain the number of outbreaks and livestock in each of 15,599 cells covering the mapped surface of the country. A spatial scan statistic was applied to the density-smoothed data assuming that the outbreaks had a Poisson distribution. Results were compared with those obtained using a spatial scan statistic on provincially aggregated data. Application of the spatial scan statistic on the density-smoothed data allowed identification of clusters (P<0.01) related more to the actual geographic distribution of cases (expert opinion) and of animals at risk, than to the distribution of the provinces. Significant clusters of FMD were identified that coincided with roads, neighboring countries, and high-density population areas, suggesting that the region may represent a route for cross-continent transmission of FMD.

Animals↗

PubMed2003

Technical description of RODS: a real-time public health surveillance system.

This report describes the design and implementation of the Real-time Outbreak and Disease Surveillance (RODS) system, a computer-based public health surveillance system for early detection of disease outbreaks. Hospitals send RODS data from clinical encounters over virtual private networks and leased lines using the Health Level 7 (HL7) message protocol. The data are sent in real time. RODS automatically classifies the registration chief complaint from the visit into one of seven syndrome categories using Bayesian classifiers. It stores the data in a relational database, aggregates the data for analysis using data warehousing techniques, applies univariate and multivariate statistical detection algorithms to the data, and alerts users of when the algorithms identify anomalous patterns in the syndrome counts. RODS also has a Web-based user interface that supports temporal and spatial analyses. RODS processes sales of over-the-counter health care products in a similar manner but receives such data in batch mode on a daily basis. RODS was used during the 2002 Winter Olympics and currently operates in two states-Pennsylvania and Utah. It has been and continues to be a resource for implementing, evaluating, and applying new methods of public health surveillance.

Algorithms↗

PubMed1996

A clinically useful diabetes electronic medical record: lessons from the past; pointers toward the future.

We have analysed the deficiencies of paper medical records in facilitating the care of patients with diabetes and have developed an electronic medical record that corrects some of them. The diabetes electronic medical record (DEMR) is designed to facilitate the work of a busy diabetes clinic. Design principles include heavy reliance on graphic displays of laboratory and clinical data, consistent color coding and aggregation of data needed to facilitate the different types of clinical encounter (initial consultation, continuing care visit, insulin adjustment visit, dietitian encounter, nurse educator encounter, obstetric patient, transplant patient, visits for problems unrelated to diabetes). Data input is by autoflow from the institutional laboratories, by desk attendants or on-line by all users. Careful attention has been paid to making data entry a point and click process wherever possible. Opportunity for free text comment is provided on every screen. On completion of the encounter a narrative text summary of the visit is generated by the computer and is annotated by the care giver. Currently there are about 7800 patients in the system. Remaining challenges include the adaptation of the system to accommodate the occasional user, development of portable laptop derivatives that remain compatible with the parent system and improvements in the screen structure and graphic display formats.

Diabetes Mellitus↗

PubMed2005

Role of AFP mRNA expression in peripheral blood as a predictor for postsurgical recurrence of hepatocellular carcinoma: a systematic review and meta-analysis.

AIM: To identify the role of alpha-fetoprotein (AFP) mRNA expression in peripheral blood one week after surgery as a predictor for recurrence of hepatocellular carcinoma (HCC). METHODS: Published studies fulfilling the selection criteria were identified by searching several databases online. After a methodology assessment using a quality scale designed by European Lung Cancer Working Party, data in each research were aggregated by means of meta-analysis. RESULTS: Altogether 368 cases were included in the 9 selected studies, which fulfilled the selection criteria. The quality scores ranged from 35% to 84% with a median score of 55%. The 'design' subscore had the lowest median value (38%). By aggregating the data, a high chi2 value (77.576) was presented. The fail-safe number was 136 and 64 for P = 0.05 and 0.01, respectively. CONCLUSION: AFP mRNA expression in peripheral blood 1 wk after surgery correlated with the recurrence of HCC and was a good predictor for tumor recurrence.

Biomarkers, Tumor↗

PubMed2005

Multi-cultural surveillance for ectopic pregnancy: California 1991-2000.

BACKGROUND: National surveillance for ectopic pregnancy (EP), the primary cause of maternal death in the first trimester, began in 1970. EP rates peeked during the late 1980s and have been highest for African Americans. However, limited reports on EP rates exist for other racial/ethnic groups. OBJECTIVES: To report state-level, multicultural trends in EP rates from 1991 to 2000. METHODS: Secondary data analysis of the California hospital discharge database collected by the Office of Statewide Health Planning and Development by using codes 633.0-633.9, from the International Classification of Diseases, Ninth Revision. EP rates are reported per 1000 pregnancies. RESULTS: From 1991 to 2000, 62,839 EP were reported in California. Mean EP rate was 11.2/1000, decreased from 15/1000 to 9.3/1000, and varied significantly by race/ethnicity and age. EP rates were highest among African Americans (25/1000) and lowest among Hispanics (7.7/1000); African Americans had higher odds of having EP relative to non-Hispanic Whites (odds ratio [OR] 2.14, 95% confidence interval [CI] 2.09-2.19). Women 35-44 years of age had the highest EP rates (17.6/1000) and higher odds of having EP compared to other age groups (OR 2.45, 95% CI 2.39-2.50). The highest rate of EP was found among African Americans 35-44 years of age (43.1/1000). CONCLUSIONS: The study showed declining EP rates in California for all groups but highlights disparities in EP rates and the attenuated rate of decline for African Americans, which places them at highest risk of death in the first trimester. This study demonstrates the usefulness of analyzing state-level data that may differ from aggregated national data when studying culturally diverse populations.

Adolescent↗

PubMed1985

Action of platelet-activating factor on type 1 diabetic human platelets.

Platelets from patients with type 1 diabetes have exhibited more sensitivity to aggregation when compared with platelets from controls without diabetes after challenge with platelet-activating factor (PAF). The production of thromboxane B2 (TxB2) and 12-hydroxyeicosatetraenoic acid (12-HETE) and the release of 5-hydroxytryptamine (5HT) were increased when the platelets were challenged by PAF (5.0 X 10(-6) mol/L and 1.0 X 10(-6) mol/L). The production of TxB2 and 12-HETE and the release of 5HT were related to the irreversible biphasic aggregation profiles observed in the patients with diabetes. Inhibition of thromboxane A2 (TxA2) production by acetylsalicylic acid abolished the secondary wave of aggregation of platelets from patients with diabetes, changing an irreversible aggregation to a reversible one. Inhibition of both TxA2 and 12-HETE production by eicosatetraynoic acid did not contribute further to the inhibition caused by acetylsalicylic acid alone, indicating that 12-HETE was not involved in the secondary wave of aggregation. These data show that the increased aggregation observed in the platelets from the group with diabetes in response to PAF results in part from their higher production of TxA2 and release of 5HT.

Adult↗

PubMed1977

[Role of prostaglandin endoperoxides in thrombocyte aggregation].

Phospholipase A and lysolecithin stimulated the thromboplastic factor release reaction and the red blood cells and platelets aggregation. According to polarographic research data, these aggregating agents brought about oxygen consumption in the platelet-containing medium. In all probability, this indicated that endoperoxides, an intermediate product of prostaglandin synthesis, were created under the mentioned conditions. Albumin failed to prevent the oxygen release reaction and its consumption, provoked by phospholipase A and lysolecithin, but totally inhibited their aggregation capacity. On the contrary, aspirin, blocked the oxygen consumption by platelets, without producing any significant effect on the lysolecithin aggregation capacity. It is assumed that the blood formed elements aggregation is due to perturbation of their membrane lipid-protein structure, and not to the endoperoxide synthesis.

Albumins↗

PubMed2004

Desmin aggregate formation by R120G alphaB-crystallin is caused by altered filament interactions and is dependent upon network status in cells.

The R120G mutation in alphaB-crystallin causes desmin-related myopathy. There have been a number of mechanisms proposed to explain the disease process, from altered protein processing to loss of chaperone function. Here, we show that the mutation alters the in vitro binding characteristics of alphaB-crystallin for desmin filaments. The apparent dissociation constant of R120G alphaB-crystallin was decreased while the binding capacity was increased significantly and as a result, desmin filaments aggregated. These data suggest that the characteristic desmin aggregates seen as part of the disease histopathology can be caused by a direct, but altered interaction of R120G alphaB-crystallin with desmin filaments. Transfection studies show that desmin networks in different cell backgrounds are not equally affected. Desmin networks are most vulnerable when they are being made de novo and not when they are already established. Our data also clearly demonstrate the beneficial role of wild-type alphaB-crystallin in the formation of desmin filament networks. Collectively, our data suggest that R120G alphaB-crystallin directly promotes desmin filament aggregation, although this gain of a function can be repressed by some cell situations. Such circumstances in muscle could explain the late onset characteristic of the myopathies caused by mutations in alphaB-crystallin.

Cell Line↗

PubMed1978

A collision analysis of lymphoid cell aggregation.

We have obtained data on the frequency of aggregates of different size classes and on the maximum aggregate diameter of lymphoid cells subjected to aggregation in the laminar shear field of a Couette viscometer. Maximum aggregate diameter reached a plateau level during aggregation. This plateau is considered to be the result of a balance between the hydrodynamic shear forces tending to resist the formation of aggregates, and the adhesive forces of the aggregated cells tending to resist dissociation. Stepwise-increases in the shear rate produced aggregates of progressively smaller maximum diameter until the limiting (i.e. control equivalent) diameter was reached. Equations governing these stepwise changes in aggregate diameter were obtained by regression analysis, and an estimate of the force of dissociation (FD) was made from derived values of the critical shear rate. Thymocytes (FD=2.54 X 10(-6) N m-2/cell) were found to be more adhesive than lymphocytes (FD=2.05 X 10(-6) N m-2/cell), in agreement with current concepts. The observed data on aggregate frequency were seen to be of poor fit with a model of aggregation derived by collision analysis of the aggregation process. This led us to consider the possibility that all cells may not share the same probability of forming an adhesion. We thus derived further models of aggregation in which some fraction of the total cells was considered to have enhanced possibilities of a collision producing an adhesion. Of the models we considered, a 15% preferred fraction offered best agreement with the experimental observations. We therefore conclude that the populations of cells studied in this report are not 'homogenous' in that some cells are more adhesive than others. Alterations in the percentage of the preferred fraction of cells will lead to different aggregate-frequency indices. Such changes might be expected to occur during the initial stages of carcinoma development.

Animals↗

PubMed2001

The use of census data for determining race and education as SES indicators: a validation study.

PURPOSE: Little research has examined the validity of using census data to determine an individual's socio-economic status (SES), as measured by race and educational level. This study assessed the accuracy of using aggregate level data from United States Census Block Groups in determining race and education SES indicators in a cohort of women from North Carolina. METHODS: The study analyzed patient data from the Carolina Mammography Registry and 1990 United States Census in 21 North Carolina counties. Women (n = 39,546) were geocoded to their census block group and their block group characteristics (surrogate measures) were validated with their self-reported values on race and education. An analysis was performed to explore whether using these surrogate measures would affect measured associations with the self-reported values. RESULTS: Whites were accurately identified (84.8%) more consistently than Blacks (14.1%) regardless of their urban/rural status. Women without a high school diploma or equivalent were accurately identified (56.2%) more often than those with higher education levels (45.9%). Analyses using the surrogate measures were significantly different than the true values according to chi-square statistics. CONCLUSIONS: Use of census data to derive SES indicators tends to be more accurate for the majority than the minority population. Researchers must be sensitive to the ecologic fallacy when using aggregate level data such as the census to determine individual level characteristics.

Black or African American↗

PubMed2005

Domiciliary oxygen for chronic obstructive pulmonary disease.

BACKGROUND: Domiciliary oxygen therapy has become one of the major forms of treatment for hypoxaemic chronic obstructive pulmonary disease (COPD) patients. OBJECTIVES: To determine the effect of domiciliary oxygen therapy on survival and quality of life in patients with COPD. SEARCH STRATEGY: Randomised controlled trials (RCTs) were identified using the Cochrane Airways Group COPD register using the search terms: home OR domiciliary AND oxygen. Searches were current as of January 2005. SELECTION CRITERIA: Any RCT in patients with hypoxaemia and COPD that compared long term domiciliary or home oxygen therapy with a control treatment. DATA COLLECTION AND ANALYSIS: Data extraction was performed independently by two reviewers. MAIN RESULTS: Six randomised controlled trials were identified. Survival data was aggregated from two trials of the treatment of nocturnal oxygen therapy in patients with mild to moderate COPD and arterial desaturation at night. Survival data was also aggregated from two trials of continuous oxygen therapy versus no oxygen therapy in mild to moderate COPD. Data could not be aggregated for the other two trials because of differences in trial design and patient selection. Nott 1980: continuous oxygen therapy versus nocturnal oxygen therapy: there was a significant improvement in mortality after 24 months (Peto odds ratio 0.45, 95% confidence interval 0.25 to 0.81). MRC 1981: domiciliary oxygen therapy versus no oxygen therapy: there was a significant improvement over five years in mortality in the group receiving oxygen therapy (Peto odds ratio 0.42, 95% confidence interval 0.18 to 0.98). In the two studies of nocturnal oxygen versus no oxygen therapy in patients with COPD and arterial desaturation at night: there was no difference in mortality between treated and non treated groups for either trial or when the trials were aggregated. In the two trials of long-term oxygen therapy versus no oxygen therapy in COPD patients with mild to moderate hypoxaemia: there was no effect on survival for up to three years of follow up. AUTHORS' CONCLUSIONS: Long-term home oxygen therapy improved survival in a selected group of COPD patients with severe hypoxaemia (arterial PaO2 less than 55 mm Hg (8.0 kPa)). Home oxygen therapy did not appear to improve survival in patients with mild to moderate hypoxaemia or in those with only arterial desaturation at night.

Home Care Services↗

PubMed1999

Zinc-dependent activation of the plasma kinin-forming cascade by aggregated beta amyloid protein.

Beta Amyloid proteins (Abeta) of 38, 40, and 42 amino acids long were assessed for their ability to activate the plasma kinin-forming cascade in vitro. Incubation with a mixture of Factor XII (Hageman Factor), prekallikrein, and high-molecular-weight kininogen (HK) led to conversion of prekallikrein to kallikrein that was dependent on zinc ion. No activation occurred if Factor XII was omitted. There was rapid generation of bradykinin equal to the molar HK input indicating complete cleavage. Incubation of aggregated Abeta with diluted human plasma also led to prekallikrein activation and HK cleavage. Activation of the cascade by Abeta (1-38) was dependent upon its preincubation time in buffer, suggesting that aggregation of Abeta is required, and studies with Abeta (1-40) revealed time-dependent aggregation by microscopy and augmented zinc-dependent binding of both Factor XII and HK to aggregated Abeta. These data demonstrate that aggregated Abeta can bind and activate proenzymes of the plasma kinin-forming cascade in a zinc-dependent reaction to release bradykinin and is of sufficient potency to do so at physiologic concentrations of each protein and in the presence of naturally occurring protease inhibitors.

Amyloid beta-Peptides↗

PubMed1988

Effects of aggregating agents and of blood cells on the aggregation of whole blood by impedance technique.

In this study the effects of different aggregating agents on platelet rich plasma (PRP) and whole blood (WB) aggregation, as determined by the optical and the impedance method, are evaluated. While the response of PRP to PAF, epinephrine and sodium arachidonate was comparable using the two methods, significantly greater amounts of collagen and ADP were required to obtain 50% aggregation of PRP. In addition, when the response of WB to the aggregation induced by different agents was compared to that of PRP (impedance method), no difference between WB and PRP was detected, with exception for ADP and sodium arachidonate induced aggregation. In vitro data on the aggregation of PRP induced by collagen and ADP in the presence of different concentrations of red cells and of white cells, suggest that WC and RC may affect PRP aggregation only in selected experimental conditions.

Adult↗

PubMed2005

Pseudorabies virus infections in wild boar: data visualisation as an aid to understanding disease dynamics.

Spatio-temporal survey data often form the main decision support in disease management. Consequently, disease managers rely on adequate description of the data supplied from epidemiological analysis. Practically speaking, such a description comprises of a visualisation, a deduced hypothesis and a statistical evaluation of the hypothesis. Prior to the application of traditional methods of data visualisation and hence data description, an aggregation of the data is required. This paper illustrates the resulting uncertainty in hypotheses that can be generated by traditional analytical techniques. Additionally, a method of avoiding this typical drawback in traditional data exploration is demonstrated: This is the use of data movies. Data from a 10-year study on the spread of pseudorabies virus (PrV) infections in wild boar populations were revisited. The visualisation of the data using a data movie instead of using traditional approaches for the first time enabled immediate observation of spreading infection in time and space. This dynamic perception of the spread drastically changes the understanding of the epidemiology of the virus. The paper demonstrates how data movies can account for the complete information contained within the data set. It is concluded that data movies can provide a more appropriate starting point. We recommend the data movie approach as an important addition in the epidemiological toolbox, because data movies can easily be integrated into the usual demonstration and publication process.

Animals↗