Herbivore-induced plant volatiles, not natural enemies, mediate a positive indirect interaction between insect herbivores.

Many insect herbivores engage in apparent competition whereby two species interact through shared natural enemies. Upon insect attack, plants release volatile blends that attract natural enemies, but whether these volatiles mediate apparent competition between herbivores is not yet known. We investigate the role of volatiles that are emitted by bean plants upon infestation by Acyrthosiphon pisum aphids on the population dynamics and fitness of Sitobion avenae aphids, and on wheat phloem sap metabolites. In a field experiment, the dynamics of S. avenae aphids on wheat were studied by crossing two treatments: exposure of aphid colonies to A. pisum-induced bean volatiles and exclusion of natural enemies. Glasshouse experiments and analyses of primary metabolites in wheat phloem exudates were performed to better understand the results from the field experiment. In the field, bean volatiles did not affect S. avenae dynamics or survival when aphids were exposed to natural enemies. When protected from them, however, volatiles led to larger aphid colonies. In agreement with this observation, in glasshouse experiments, aphid-induced bean volatiles increased the survival of S. avenae aphids on wheat plants, but not on an artificial diet. This suggests that volatiles may benefit S. avenae colonies via metabolic changes in wheat plants, although we did not find any effect on wheat phloem exudate composition. We report a potential case of associational susceptibility whereby plant volatiles weaken the defences of receiving plants, thus leading to increased herbivore performance.

Effects of continuous versus pulsed drought stress on physiology and growth of wheat.

In the course of climate change, crop plants are exposed to both altered precipitation volumes and frequencies in many cultivation areas. Reduced water availability and longer periods without precipitation can lead to changes in plant physiology and productivity. In this greenhouse study, we investigated physiological responses, including maximum quantum yield of photosystem II (Fv /Fm ) and water use efficiency (WUE) as well as diverse productivity-related parameters, including grain yield per plant, to continuous (irrigated three times a week) versus pulsed (once a week) irrigation in spring wheat (Triticum aestivum L.). In both drought regimes, plants were exposed to four different irrigation volumes. Fv /Fm was not influenced by irrigation treatment but was significantly higher after 6 weeks of drought than after 2 weeks. WUE increased with decreasing irrigation volume and based on generative biomass; it was higher in continuously-watered compared to pulsed-watered plants that received a similar amount of water over the experiment. Infrequent irrigation led to a reduction in grain yield of up to 51%. This lower productivity was primarily caused by fewer tillers in pulsed-watered plants. Additionally, at low water volume the thousand grain weight (TGW) was lower in infrequently-compared to frequently-watered plants. In contrast, the number of grains per ear was higher in pulsed-watered plants. In conclusion, reduced irrigation frequency, next to a decrease in irrigation volume, negatively affects WUE and grain yield of spring wheat. These results might have important implications for irrigation scheduling and breeding programmes under a changing climate.

Interactions between the jasmonic and salicylic acid pathway modulate the plant metabolome and affect herbivores of different feeding types.

The phytohormones jasmonic acid (JA) and salicylic acid (SA) mediate induced plant defences and the corresponding pathways interact in a complex manner as has been shown on the transcript and proteine level. Downstream, metabolic changes are important for plant-herbivore interactions. This study investigated metabolic changes in leaf tissue and phloem exudates of Plantago lanceolata after single and combined JA and SA applications as well as consequences on chewing-biting (Heliothis virescens) and piercing-sucking (Myzus persicae) herbivores. Targeted metabolite profiling and untargeted metabolic fingerprinting uncovered different categories of plant metabolites, which were influenced in a specific manner, indicating points of divergence, convergence, positive crosstalk and pronounced mutual antagonism between the signaling pathways. Phytohormone-specific decreases of primary metabolite pool sizes in the phloem exudates may indicate shifts in sink-source relations, resource allocation, nutrient uptake or photosynthesis. Survival of both herbivore species was significantly reduced by JA and SA treatments. However, the combined application of JA and SA attenuated the negative effects at least against H. virescens suggesting that mutual antagonism between the JA and SA pathway may be responsible. Pathway interactions provide a great regulatory potential for the plant that allows triggering of appropriate defences when attacked by different antagonist species.

Representation of practice guidelines with XML--modeling with XML schema.

OBJECTIVES: Data and information in medicine are mainly represented in slightly structured or even unstructured, narrative text documents. It is nearly impossible to detect and handle relationships between data elements within narrative documents or to retrieve parts of documents that contain specific information. But information access and retrieval are essential to serve the delivery and application of evidence-based medicine. METHODS: The eXtensible Markup Language (XML) provides a standard means to explicitly describe a document's structure and to identify meaningful elements inside textual narrations. Information about the state-of-the-art medical care can be delivered to the physician by different means and media. Clinical practice guidelines are thought to be one possible solution to summarize and present current medical evidence. RESULTS: The structuring of resources containing medical information with XML can facilitate the provision of problem-specific medical information at the point of care by improving content retrieval and presentation. In our project, the XML Schema is used for the electronic representation in order to structure guidelines (and other text-based resources) in a standardized way. CONCLUSION: The transition from unstructured textual data towards structured and coded data will be a migration process. One of the premises of our approach is that the structure that is defined by the information model doesn't restrict the content of the documents. This approach may fill the gap between computerized, algorithmic guideline recommendations and text-based guideline distributions.

Towards case-based performance measures: uncovering deficiencies in applied medical care.

Measures are designed to evaluate the processes and outcomes of care associated with the delivery of clinical (and non-clinical) services. They allow for intra- and interorganizational comparison to be used continuously to improve patient health outcomes. The use of performance measures always means to abstract the complex reality (medical scenarios and procedures) in order to provide an understandable and comparable output. Measures can focus on global performance. The more detailed data are available the more specific judgements with respect to the appropriateness of clinical decision-making and implementation of evidence are feasible. Externally reported measures are intended both to inform and lead to action. By providing this information, deficiencies in patient care and unnecessary variations in the care process can be uncovered. Such variations have contributed to disparities in morbidity and mortality. The developments in information technology, especially world-wide interconnectivity, standards for electronic data exchange and facilities to store and manage large amounts of data, offer the opportunity to analyse health-relevant information in order to make the delivery of healthcare services more transparent for consumers and providers. Global performance measures, such as the overall life expectancy (mortality) in a country, can give a rough orientation of how well health systems perform but they do not offer general solutions nor specific insights into care processes that have to be improved. In contrast to population-based measures, case-based performance measures use a defined group of patients depending on specific patient characteristics and features of disease. By means of these measures we are able to compare the number of patients that receive a necessary medical procedure against those patients who do not. The use of case-based measures is a bottom-up approach to improve the overall performance in the long run. They are not only a tool for global orientation but can offer a straightforward link to the areas of deficient care and the underlying procedures. Performance measures are relevant to providers as well as consumers, from their own individual perspective. Cased-based measures focus on the management of individual patient. This approach to performance measurement can inform physicians in a meaningful and constructive way by monitoring their individual performance and by pointing out possible areas of improvement.

[Current approaches for the implementation of guidelines by means of information technologies]. / Aktuelle Ansätze zur Implementierung von Leitlinien mittels Informationstechnologien.

Clinical practice guidelines (CPGs) play an increasingly important role in the harmonisation process of health care delivery and disease management. It is known that nationally or internationally produced guidelines that have no consistent implementation strategy, have limited impact in changing physicians' behaviour and patterns of care. The literature provides evidence for the effectiveness of computerisation of CPGs for increasing compliance and improving patient outcomes. The integration of knowledge-based functions for decision support or monitoring in clinical information systems is one effective way. Another approach relies on the original, mostly text-based, guidelines. By structuring these resources with the eXtensible Markup Language (XML) we are able to improve the availability of clinically relevant knowledge at the point of care. XML allows for in-context searching and the customized presentation of guideline content. We are confident that this new approach will improve the acceptance and the benefits of the increasing number of guidelines in medicine.

Value of XML in the implementation of clinical practice guidelines--the issue of content retrieval and presentation.

The purpose of guidelines in clinical practice is to improve the effectiveness and efficiency of clinical care. It is known that nationally or internationally produced guidelines which, in particular, do not involve medical processes at the time of consultation, do not take local factors into account, and have no consistent implementation strategy, have limited impact in changing either the behaviour of physicians, or patterns of care. The literature provides evidence for the effectiveness of computerization of CPGs for increasing compliance and improving patient outcomes. Probably the most effective concepts are knowledge-based functions for decision support or monitoring that are integrated in clinical information systems. This approach is mostly restricted by the effort required for development and maintenance of the information systems and the limited number of implemented medical rules. Most of the guidelines are text-based, and are primarily published in medical journals and posted on the internet. However, internet-published guidelines have little impact on the behaviour of physicians. It can be difficult and time-consuming to browse the internet to find (a) the correct guidelines to an existing diagnosis and (b) and adequate recommendation for a specific clinical problem. Our objective is to provide a web-based guideline service that takes as input clinical data on a particular patient and returns as output a customizable set of recommendations regarding diagnosis and treatment. Information in healthcare is to a very large extent transmitted and stored as unstructured or slightly structured text such as discharge letters, reports, forms, etc. The same applies for facilities containing medical information resources for clinical purposes and research such as text books, articles, guidelines, etc. Physicians are used to obtaining information from text-based sources. Since most guidelines are text-based, it would be practical to use a document-based solution that preserves the original cohesiveness. The lack of structure limits the automatic identification and extraction of the information contained in these resources. For this reason, we have chosen a document-based approach using eXtensible Markup Language (XML) with its schema definition and related technologies. XML empowers the applications for in-context searching. In addition it allows the same content to be represented in different ways. Our XML reference clinical data model for guidelines has been realized with the XML schema definition. The schema is used for structuring new text-based guidelines and updating existing documents. It is also used to establish search strategies on the document base. We hypothesize that enabling the physicians to query the available CPGs easily, and to get access to selected and specific information at the point of care will foster increased use. Based on current evidence we are confident that it will have substantial impact on the care provided, and will improve health outcomes.

DTDs go XML schema--a tools perspective.

Document Type Definitions (DTDs) are widely used to describe the structure of XML documents. The Clinical Document Architecture (CDA) and the Guideline Element Model (GEM) are examples from the healthcare domain. XML schemas provide another way to describe types of XML documents. In this paper we aim to advocate XML schemas from the perspective of an ANSI standard, the XML based CDA from HL7 (ANSI/HL7 CDA R1.0-2000). It turned out that existing tools do not fully exploit the knowledge contained in DTDs and XML schemas. The result of this study is a set of tools (DTD to XML Schema translator, DTD and XML schema browser, XML editor), which can be downloaded from the official W3C site and which work with any DTD and XML schema.

Presentation of problem-specific, text-based medical knowledge: XML and related technologies.

Systematic reviews of the impact of clinical decision support systems on provider behavior and patient outcome have shown evidence of benefit. Knowledge-based functions for decision support or monitoring that are integrated in clinical information systems are a potentially effective way. But these concepts are restricted by the efforts required for development and maintenance of the information systems and the limited number of implemented medical rules. Physicians are familiar to get their information from text-based sources. It seems to be straight-forward to rely on a document-based solution in order to present problem-specific information at the point of care. We have developed a concept for context-sensitive retrieving and presentation of text-based medical knowledge (textbook of internal medicine) using the eXtensible Markup Language (XML) and related technologies. This concept can facilitate the electronic query and presentation of this resource. XML may replace narrative text as a storage format and allows to structure the data in a stepwise fashion. On the basis of structured data we are able to improve the search quality for clinical information and its presentation which forms a crucial pre-requisite for the use of the information and the implementation of evidence-based care in the clinical routine.

Structured clinical documentation for the assessment of medical care.

The developing infrastructure for tumour documentation in Germany offers the unique opportunity to provide the physicians with useful clinical information, to evaluate standards of care, and get an impression about the "real-world-effectiveness" of cancer care. In order to compare and evaluate diagnostic and therapeutic approaches in different medical institutions or health care systems, the systematic, patient-oriented, treatment accompanying tumour documentation is a compelling requirement. Our intention is to optimise content and extent of the collected information to characterise the different dimensions of the quality of medical care the best possible. We found that most of the problems are deriving from the contextually and timely correct documentation of medical procedures which includes diagnostic as well as therapeutic interventions. The content of the documentation together with standards of care, such as Clinical Practice Guidelines, should be parallel developed in interdisciplinary co-operation. This way, the fundamental domains of performance, such as appropriateness, availability, continuity, safety, effectiveness, and timeliness of medical care can described and evaluated objectively.

XML structured clinical information: a practical example.

At Giessen university, a drug formulary comprising drug data and treatment guidelines is supplied to clinical users who can access the drug information by an index of drug substances and drug substance groups. The guideline itself is a textual description with related information such as drug substances and drug brand names. Since clinical users also want to access the information by drug names, we had to extract this information from the textual descriptions. The extraction however caused some effort. In order to not repeat this effort in the future, we used the eXtensible Markup Language (XML) to restructure the information sources. This paper describes our experiences with this kind of legacy to XML conversion and outlines a possible migration path towards the XML technology.

Combining dictionary techniques with extensible markup language (XML)--requirements to a new approach towards flexible and standardized documentation.

In oncology various international and national standards exist for the documentation of different aspects of a disease. Since elements of these standards are repeated in different contexts, a common data dictionary could support consistent representation in any context. For the construction of such a dictionary existing documents have to be worked up in a complex procedure, that considers aspects of hierarchical decomposition of documents and of domain control as well as aspects of user presentation and models of the underlying model of patient data. In contrast to other thesauri, text chunks like definitions or explanations are very important and have to be preserved, since oncologic documentation often means coding and classification on an aggregate level and the safe use of coding systems is an important precondition for comparability of data. This paper discusses the potentials of the use of XML in combination with a dictionary for the promotion and development of standard conformable applications for tumor documentation.

Confronting actual practice with practice guidelines in oncology.

Improving health care quality requires the availability of data to identify and eliminate unnecessary variations in the care process. Variations can be caused by an ineffective implementation of research findings or by obstacles to the translation of research into clinical practice. The analysis of current patterns of care by the use of routine data from electronic patient records or clinical registries may help highlight these deficiencies in actual care. The growing infrastructure of information technologies and the knowledge about clinically relevant variations of routine practice may help us understand the mechanisms that are impeding the translation of research into practice. There is a need to scrutinize these variations of practice and the barriers to guideline implementation. We think that an understanding and open discussion of such reasons may help, to continuously improve the quality of patient care. This process facilitates efforts and strategies to implement evidence-based medicine in the daily routine.

Transferring data from one EPR to another: content--syntax--semantic.

When data are transmitted between electronic patient record (EPR) systems, we can distinguish several tasks. One task is the definition of structure and semantic content of the data in a message structure. Another task is the mapping of the sending EPR's structure to this message structure. A third task is the mapping of the message structure to the receiving EPR's structure. We describe an approach, which distinguishes clearly between these different tasks and activities. Using this approach we have implemented a data transfer procedure between a cancer registry application and a middleware for healthcare information systems. Our experience showed that the proposed systematic approach helped identify problems for data transfer in an early design phase. It also allowed us to limit modifications of the data exchange procedure to certain tasks or activities when one of the EPR applications was updated. In the end, we could even exchange the underlying message format without having to reimplement the complete interface.

How to structure clinical information: a practical example.

In the frame of an European telemedicine project, we have designed and implemented an Andrology server that provides the user (e.g. physicians, students) with a set of anonymized andrology cases. Within this context we faced the problem of re-structuring existing clinical information sources and gained some experience on how much of the problem might be solved by the software engineer. This paper presents a method that partially automates the maintenance of the andrology case collection. Moreover, the potential benefit of XML for information representation will be discussed.

A model for integration and continuous development of standards for tumour documentation using relational database techniques and extensible markup language.

In oncology various international and national standards exist for different aspects of a disease. These standards, maintained by different organisations, have multiple relationships with each other. A common data dictionary like UMLS would facilitate the reorganisation of such relationships when a new version of a standard is published. While the modelling of relationships usually is restricted to types having a relevant frequency, there are often relationships which are expressed in texts like definitions or explanations. Such texts are a very important supplement for the acceptance and the safe use of coding systems, but often are neglected when implementing coding systems in computerised systems, because they are costly to implement. This paper discusses potentials when integrating various sources in a common, database based dictionary enhanced by XML (Extensible Markup Language) techniques.

Plug and play--fiction or reality?

This paper discusses some experiences with the integration of a tumor documentation system into a distributed healthcare environment using a new European middleware technology. Although the middleware already offers a considerable support to the software engineer, further facilities have been suggested and partially implemented in order to accelerate integration scenarios.

Post-integration of a tumor documentation system into a HIS via middleware.

Integrating autonomous applications is a difficult task since they usually represent similar informations in different data schemes. Any communication requires an agreement of sender and receiver on a common data representation. The number of interfaces to convert one data representation into another is minimized if all participants of an information system agree on one data representation such as Health Level Seven (HL7) or Edifact. Even more convenient is the use of a middleware solution like the Distributed Healthcare Environment (DHE) that keeps message transfer completely transparent to the integration process. This paper discusses a project that aims at the integration of a cancer registry system into a DHE based Hospital Information System (HIS). The project is a cooperation between the universities of Giessen and Magdeburg within the framework of the European Communities Telematics Research Project HC 1019 HANSA (Healthcare Advanced Networked System Architecture). The concept of a so called 'DHE-Adapter' to integrate existing legacy systems is explained. This adapter converts a data or message format of a legacy system into calls of the DHE programming interface. To develop a DHE-Adapter for our cancer registry system we intend to design a DHE-Adapter-Generator which would be able to produce DHE-Adapters for different systems and export formats, e.g. HL7 or Edifact. That would allow a variety of software vendors to integrate their products into the DHE without entering deeply into the DHE's programming interface.

Plug and play integration into a healthcare information system.

This paper discusses some experiences with the integration of a tumor documentation system into a distributed healthcare environment using a new European middleware technology. Although the middleware already offers a considerable support to the software engineer further facilities have been developed in order to accelerate integrations. Such facilities arised from the software engineering principle of separating reusable parts and non-reusable parts.