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Biomedical subjects

U Forsum

Publications and source records attributed to U Forsum.

At least 37 records · Page 2Linked to original sources
PubMed1997

Propionebacterium acnes in cultures from ventriculo-peritoneal shunts: infection or contamination?

We have examined the accuracy of our present CSF sampling technique in 14 referred patients with suspect shunt dysfunction. The study was performed comparing culture results from shunt reservoir punctures and sham samples from skin tissue fluid close to the reservoirs. Propionebacterium acnes (P acnes) was found in five of fifteen cultures from reservoir punctures and in five of fifteen sham procedures. Positive cultures correlated in two cases. Thirteen of the fourteen patients included in the study were followed clinically and their symptoms disappeared without antibiotic or surgical treatment. One patient was treated surgically. We conclude that bacterial growth in cultures from shunt reservoirs in cases with P acnes should be interpreted with great caution, as our findings indicate that they may be skin contaminations.

Adolescent↗
PubMed1997

Human dendritic cells handling of binding, uptake and degradation of free and IgG-immune complexed dinitrophenylated human serum albumin in vitro.

The handling of free and IgG-complexed dinitrophenylated human serum albumin (DNP-HSA) by human dendritic cells (DC) cultured with granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-4 (IL-4) was studied. It has been shown that the amount of uncomplexed or IgG-complexed antigen required by DC to start an immune response is low compared with other antigen-presenting cells. We therefore examined whether such efficient presentation of immune complexes is due to an enhanced Fc gamma RII-mediated endocytosis or to a specialized and efficient antigen handling, i.e., macropinocytosis. The Fc gamma RII expression was found to be heterogeneous on the GM-CSF- and IL-4-cultured DC, i.e. it ranges from low to high expression. The handling of antigen and immune complexes revealed, that the level of binding and uptake of IgG-DNP-HSA complexes by in vitro expanded DC is low compared with free antigen. Uncomplexed DNP-HSA is probably handled either by endocytosis via receptors being more abundant and/or efficient than the Fc gamma RII or via non-receptor-mediated endocytosis. The binding and uptake of IgG-complexed DNP-HSA was blocked by anti-Fc gamma RII antibody, indicating the specificity of the interaction.

Antigen-Antibody Complex↗
PubMed1997

Role of annexins in endocytosis of antigens in immature human dendritic cells.

We have evaluated the uptake of a soluble protein antigen, denitrophenylated human serum albumin (DNP-HSA), and two different intracellular bacteria; Chlamydia trachomatis serovar L2 and Mycobacterium tuberculosis strain H37Ra, by immature human dendritic cells. These were generated by culturing progenitor cells from blood in the presence of cytokines (granulocyte-macrophage colony-stimulating factor and interleukin-4). Dendritic cells play a crucial part in antigen presentation for the induction of T-cell-dependent immune responses in various tissues. Recently, macropinocytic and phagocytic activity has been shown for immature dendritic cells of mouse, rat and human origin. In the present study, macropinocytosis characterized the uptake of the soluble protein-antigen DNP-HSA, whereas the C. trachomatis were ingested via receptor-mediated endocytosis in coated pits, and opsonized M. tuberculosis via phagocytosis. To follow the intracellular routes of the antigens, their positions were compared with the localization of annexins, a family of Ca(2+)-and phospholipid-binding proteins, involved in membrane fusion, aggregation and transport of different vesicles. To elucidate further the intracellular pathway of the antigens, two other proteins, lysosome-associated membrane protein-1 (LAMP-1) and cathepsin D, were labelled. They are known to colocalize with major histocompatibility complex class II compartments in the immature dendritic cells. We observed a distinct translocation of annexin V to DNP-HSA containing endosomes, and annexin III to vesicles with C. trachomatis. Furthermore, annexin III, IV and V redistributed to phagosomes with M. tuberculosis. Both LAMP-1 and cathepsin D colocalized with DNP-HSA endosomes, and with phagosomes with M. tuberculosis. Thus, immature human dendritic cells have the capacity to phagocytose. Moreover, the handling of these antigens by dendritic cells may represent three distinct intracellular pathways, albeit some properties and compartments are shared.

Annexins↗
PubMed1997

Study of situation-dependent clinical cognition: a meta-analysis and preliminary method.

An integrated method was constructed for the study of in situ clinical reasoning. A meta-analysis of existing theories and an exploratory case study were performed. Twelve physicians at the department of otorhinolaryngology, and three physicians and three biomedical technologists at the clinical microbiological laboratory of an 800-bed university hospital were involved in the evaluation of the method. The meta-analysis identified situations where practitioners face assignments for which they follow no routine strategy as suitable starting points for the development of the method, in which organizational processes are presented as workflow graphs. Using the critical incident technique, problem situations in the processes are identified, and stimulated recall interviews are employed to construct a model of the situation-dependent logic used in decision-making. The case study showed that the first levels of the method could easily be used by physicians without training in organizational development or cognitive psychology. It is concluded that the method can be a means for case construction in problem-oriented learning programs that have an empirical background. It can also be used in the development of clinical organization, where training is combined with the establishment of critical paths and computer support.

Algorithms↗
PubMed1997

Extended telemedical consultation using Arden Syntax based decision support, hypertext and WWW technique.

There is an obvious need for geographic distribution of expert knowledge among several health care units without increasing the cost of on-site expertise in locations where health care is provided. This paper describes the design of a knowledge-based decision-support system for extended consultation in clinical medicine. The system is based on Arden Syntax for Medical Logic Modules and hypertext using World Wide Web technology. It provides advice and explanations regarding the given advice. The explanations are presented in a hypertext format allowing the user to browse related information and to verify the relevance of the given advice. The system is intended to be used in a closed local network. With special precautions regarding issues of safety and patient security, the system can be used over wider areas such as in rural medicine. A prototype has been developed in the field of clinical microbiology and infectious diseases regarding infective endocarditis.

Artificial Intelligence↗
PubMed1997

A qualitative study of clinicians ways of using a decision-support system.

We have studied how clinicians approached a decision-support system to manage patient cases. The design of the system under study was based on an integration of hypertext and rule-based systems. World-Wide Web technology was used for the implementation of the system. By using grounded theory and stimulated recall, we found that getting patient-specific support and continuing medical education were the two major usages of the system and that the three parameters relevance, validity, and work were important in describing how the system was experienced by the users.

Attitude to Computers↗
PubMed1996

Penetration of antibiotics in diseased antral mucosa.

OBJECTIVES: To investigate extracellular concentrations of antibiotics in inflammatory diseased sinus mucosa in critically ill patients and to find out whether there were any correlations between the concentrations of antibiotics in extracellular tissue and the presence of bacterial infection. DESIGN: Prospective case series. Sinoscopic findings were used as the criterion standard. SETTING: The general and the neurosurgical intensive care units of a tertiary care hospital. PATIENTS: Critically ill patients, nasotracheally intubated or tracheotomized, who received ventilator treatment (> 7 days) and antibiotic therapy. INTERVENTIONS: Bilateral sinoscopies were performed; antral secretions were collected for bacterial cultures; and serum and tissue samples were obtained for bioassay of antibiotic concentrations. RESULTS: The concentrations of all antibiotics found in extracellular fluid were lower than those found in serum samples. CONCLUSION: Measurable extracellular tissue concentrations of antibiotics were found in the antral mucosa, demonstrating that inflammatory maxillary sinus disease does not impede the antibiotic penetration of the mucosa or antibiotic activity in the extracellular tissue.

Adult↗
PubMed1996

Division of labour in clinical microbiology. Co-operation and fragmentation.

The aim of this study was to describe clinical microbiological practices in a hospital setting. A grounded theory was developed from qualitative data in two steps: initial participant observation to describe the clinical work-flow, and a main case study based in depth interviews and analyses of work practices using a video-based stimulated recall technique. Six physicians, 2 senior medical laboratory technologists and one head nurse were interviewed in depth based on their organizational positions. Stimulated recall interviews were conducted with 11 nurses, 6 secretaries, 6 medical laboratory technologists, and 3 physicians. An informal clinical microbiological 'workgroup' was found to co-operate around two physical objects: the microbiological sample and the laboratory request form. Work organization was divided into planning, based on science and legislations, and performance based on tradition and local supervision. None of the practitioners had a total overview of an analysis cycle, all being occupied with a discrete part of planning, practical work and information management. The conclusion of the study is that fragmentation in the division of labour may be a critical hindrance to development in clinical microbiology. If a common strategy is not shared between specialties and professions, even minor changes in routines by individual practitioners may influence patient outcome.

Cooperative Behavior↗
PubMed1996

A design for a World Wide Web decision-support system using a controlled medical terminology.

We have developed a medical decision-support system based on Arden Syntax for Medical Logic Modules and hypertext using the World Wide Web. The two representations are integrated to provide a better platform for decision support. To manage the integration a controlled medical terminology has been used as a well-defined interface between the representations. The terminology is also used to facilitate communication between specialists and non-specialists.

Artificial Intelligence↗
PubMed1995

Broad-range PCR amplification and DNA sequence analysis reveals variable motifs in 16S rRNA genes of Mobiluncus species.

Using DNA primers based on highly conserved regions of bacterial 16S ribosomal RNA genes, a technique was established for detection of Mobiluncus species by polymerase chain reaction (PCR) and hybridization analysis. Part of the 16S rRNA genes of Mobiluncus mulieris, Mobiluncus curtisii and uncharacterized Mobiluncus strains were analyzed by broad-range PCR amplification and direct DNA sequencing analysis. Sequence comparison of the partial 16S rRNA genes of Mobiluncus curtisii, Mobiluncus mulieris and atypical Mobiluncus strains studied indicated genus and species-specific motifs within the variable regions V3, V4 and V9 of 16S ribosomal DNAs. A Mobiluncus curtisii-specific primer, located within the variable region V3 of the 16S rRNA gene, was designed for Southern blot hybridization analysis of broad-range PCR products. Broad-range amplification combined with a M. curtisii-specific hybridization probe, Mob V3, distinguished between Mobiluncus curtisii, Mobiluncus mulieris, and atypical Mobiluncus strains.

Base Sequence↗
PubMed1995

Mobilization of annexin V during the uptake of DNP-albumin by human dendritic cells.

Dendritic cells play a crucial role in antigen presentation in various tissues. The endocytic capacity of these cells has been regarded as minimal, but recent work on dendritic cells from mouse spleen has disclosed that the fluid-phase traffic through late endosomes is as active in dendritic cells as in other antigen-presenting cell types. We show that cultured human dendritic cells express the annexins I, III, IV, V and VI, as detected by immunofluorescence staining. The annexins are cytosolic Ca(2+)-dependent proteins with the ability to promote vesicle aggregation and membrane fusion through their capacity to bind to membrane phospholipids. Annexin I and VI appeared to outline the cytoskeleton and the plasma membrane in cultured human dendritic cells. Studies using confocal laser scanning microscopy showed that during the endocytosis of fluorescent dinitrophenyl-conjugated albumin by dendritic cells, there was a redistribution of annexin V which was found to colocalize with vesicles containing dinitrophenyl-FITC-conjugated albumin.

Albumins↗