Analysis of Clinical Record Data for Anticoagulation Management within an EHR System

OBJECTIVES

This paper reports an evaluation of the properties of a generic electronic health record information model that were actually required and used when importing an existing clinical application into a generic EHR repository.

METHOD

A generic EHR repository and system were developed as part of the EU Projects Synapses and SynEx. A Web application to support the management of anticoagulation therapy was developed to interface to the EHR system, and deployed within a north London hospital with five years of cumulative clinical data from the previous existing anticoagulation management application. This offered the opportunity to critique those parts of the generic EHR that were actually needed to represent the legacy data.

RESULTS

The anticoagulation records from 3,226 patients were imported and represented using over 900,000 Record Components (i.e. each patient's record contained on average 289 nodes), of which around two thirds were Element Items (i.e. value-containing leaf nodes), the remainder being container nodes (i.e. headings and sub-headings). Each node is capable of incorporating a rich set of context properties, but in reality it was found that many properties were not used at all, and some infrequently (e.g. only around 0.5% of Record Components had ever been revised).

CONCLUSIONS

The process of developing generic EHR information models, arising from research and embodied within new-generation interoperability standards and specifications, has been strongly driven by requirements. These requirements have been gathered primarily by collecting use cases and examples from clinical communities, and been added to successive generations of these models. A priority setting approach has not to date been pursued - all requirements have been received and almost invariably met. This work has shown how little of the resulting model is actually needed to represent useful and usable clinical data. A wider range of such evaluations, looking at different kinds of existing clinical system, is needed to balance the theoretical requirements gathering processes, in order to result in EHR information models of an ideal level of complexity.

Effect of costimulation and the microenvironment on antigen presentation by leukemic cells

Costimulatory signals supplied by genetically modified tumor cells can enable T-cell recognition of tumor-associated antigens that were previously silent when presented by unmodified tumor cells. Although the mechanism of the CD80/CD28 costimulation has been studied extensively in the normal T-cell/antigen-presenting cell (APC) interactions, it is unclear how expression of CD80 by tumor cells mediates its effect. We demonstrate here that optimal CD80 expression on a leukemic cell enhances T-cell recognition of alloantigen primarily by lowering the level of T-cell receptor (TCR) stimulation required for activation. CD80 expression by leukemic cells leads to increased survival of activated T cells by inducing upregulation of the antiapoptotic protein BCL-2, but not BCL-X(L). The cytokine microenvironment in which T cells are activated is crucial in determining their differentiation and consequently the nature of the immune response generated. Many tumor cells produce immunosuppressive cytokines that may not favor the induction of cell-mediated immunity. In this study, the presence of CD80 on leukemic cells increased T-cell activation in vitro, but this did not result in the production of Th1 cytokines. We show that this is due to a leukemia-derived soluble factor that inhibits the production of Th1 cytokines. Optimal expression of a costimulatory molecule, therefore, enhances the ability of leukemic cells to present antigen by amplifying TCR signals, but the microenvironment generated by leukemic cells may suppress the immune response required for their eradication. Thus, strategies aimed at inducing antileukemic immunity by providing leukemic cells with costimulatory functions must ensure the presence of an appropriate microenvironment.

The Scope of Viral Vectors for the Transduction of Haemopoietic Cells

Over the last five years significant progress has been made towards the transfer of foreign genetic material to eukaryotic cells. The eventual aim to devise novel therapeutic strategies to treat human diseases, in particular solid tumours and monogenic disorders associated with various enzyme deficiency states. The easy accessibility and the ability of haemopoetic stem cells to self replicate and repopulate makes them desirable targets for gene transfer. In theory the introduction of a small number of gene modifed haemopoetic progenitor cells can allow therapy of an individual for life without any further intervention. This approach has been used for the treatment of single gene defects such as ADA deficiency. Furthermore, gene transfer technology has increasingly been exploited for bone marrow and peripheral blood stem cell marking studies, modification of cell sensitivity to cytotoxic drugs and the genetic modification of leukemic cells with the intention of inducing a leukemia specific cytotoxic T cell response. Vector development is of crucial importance for the successful delivery of genes in haemopoetic stem cells and leukemia cells. The objective of this review is to discuss in detail the properties of current vector technology that are pertinent to haemopoietic cell gene transduction.

Comparison of ribosome-inactivating proteins in the induction of apoptosis

The aim of this study was to evaluate the ability of verocytotoxin-1 (VT1), VT1 B chain alone, ricin and a hybrid toxin (RASTA2) consisting of ricin A chain linked to VT1 B chain to inhibit protein synthesis and to induce apoptosis. The lethal effects of the toxins were compared using vero cells (originating from green African monkey kidney tissue). As previously described cell death occurred through apoptosis which was quantified using the diphenylamine assay. DNA fragmentation was seen with VT1 at 10 pg/ml but there was no effect with B chain alone. Fragmentation with ricin was seen at 10 ng/ml and with RASTA2 at 1 ng/ml. Protein synthesis inhibition was measured by [(35)S]methionine incorporation. VT1 had an IC50 of 0.0024 ng/ml, B chain alone was ineffective at inhibiting protein synthesis. Ricin had an IC50 of 0.39 ng/ml and RASTA2 of 1.7 ng/ml. In vero cells the B chain of these toxins does not participate in cell killing.