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Biomedical subjects

K L Krämer

Publications and source records attributed to K L Krämer.

At least 19 recordsLinked to original sources

[Guidelines in orthopedics. Alliance of German Orthopedists. University Clinic of Orthopedics, Heidelberg].

Guidelines are systematically developed statements of the actual knowledge in order to assist doctors and patients by the decision of appropriate health care. Since 1998 the DGOT has published 22 well structured guidelines, 20 guidelines are under construction. The AWMF as the coordinator of guideline constructing of all scientific medical societies has published 629 guidelines since 1995. The publication of guidelines of the DGOT and the BVO is the first step for dissemination, next steps should be implementation und evaluation. Then it will be evident whether change in medical practice will occur.

Evidence-Based Medicine↗

[Documentation. A prerequisite for quality management].

For the judgment of the quality of medical services and for the progress of clinical medicine the comparison of data and informations of the diagnostic and therapeutic process is demanded. Therefore a systematic and concrete system of documentation should be implemented in every clinic, which consists of standard nomenclature, classification, instruments of outcome measure and documentation standards. There are a group of problems and barriers which stand in the way of this goal. It is useful to build a minimum basis data set which includes core criteria of clinical documentation in orthopedic surgery and include this in an information system so that all of these parts are considered and that a central and comparable data pool is offered for patient care, quality management and research.

Documentation↗

[30 years of computer-based clinical documentation at the Heidelberg University Orthopedic Clinic. From basic documentation to medical controlling].

An overview of the 30 years history and development of documentation and information systems in the Orthopedic University Hospital Heidelberg is presented. Since the foundation in 1967 four developmental phases can be described: first initiatives of medical doctors, establishment of a basic documentation system for scientific purposes, strategic information system planning and realisation of information systems with the possibility of controlling in medical areas and thereby steering of the services. Planning and realisation were accomplished within the framework of the masterplans and concepts of the university clinics of the state of Baden-Württemberg.

Academic Medical Centers↗

[From planning to realization of an electronic patient record].

The high complex requirements on information and information flow in todays hospitals can only be accomplished by the use of modern Information Systems (IS). In order to achieve this, the Stiftung Orthopädische Universitätsklinik has carried out first the Project "Strategic Informations System Planning" in 1993. Then realizing the necessary infrastructure (network; client-server) from 1993 to 1997, and finally started the introduction of modern IS (SAP R/3 and IXOS-Archive) in the clinical area. One of the approved goal was the replacement of the paper medical record by an up-to-date electronical medical record. In this article the following three topics will be discussed: the difference between the up-to-date electronical medical record and the electronically archived finished cases, steps performed by our clinic to realize the up-to-date electronical medical record and the problems occurred during this process.

Documentation↗

[Nomenclature and classification of complications. Standard procedure at the Heidelberg University Orthopedic Clinic].

In order to get a better data management of complications in orthopedic surgery and in order to get comparable statistics a standardisation of nomenclature and classification of complications is demanded since 1.1.1997. The Orthopedic University Clinic of Heidelberg started with a register of all early complications of all inpatients. According to a standardized nomenclature all occurred complications the doctors put in the data of complications in a database. These data were controlled, complemented and classified by members of the quality management group. This guideline consists of five parts: catalogue of diagnoses, general and special definitions, classification and an allocation table of diagnoses to grades of severity.

Academic Medical Centers↗

Synovial fibroblasts as target cells for staphylococcal enterotoxin-induced T-cell cytotoxicity.

Rheumatoid arthritis (RA) is a chronic autoimmune disease of unknown aetiology. Recently, superantigens have been implied in the pathogenesis of RA. Superantigens activate a large fraction of T cells leading to the production of cytokines and proliferation. In addition, superantigens direct cellular cytotoxicity towards major histocompatibility complex (MHC) class II-expressing cells. There is now increasing evidence that cytotoxic T cells may be involved in the pathogenesis of RA. In the inflamed synovia class II-positive synovial fibroblasts (SFC) are found. In the present study it was tested whether MHC class II-positive SFC serve as target cells for superantigen-induced cellular cytotoxicity. SFC were stimulated with interferon-gamma to express class II antigens, then they were cultivated in the presence of CD4-positive T cells with or without staphylococcal enterotoxins (SE). Cytotoxicity of T cells was measured as release of lactate dehydrogenase from SFC. Specific cytotoxicity was only found in the presence of class II-positive SFC depending on the dose of SE. Maximum lysis was seen after 20 hr. T-cell cytotoxicity was inhibited by antibodies to MHC class II antigens. The data suggest that class II-positive SFC not only function as accessory cells for SE-mediated T-cell proliferation and interleukin-2 production but may also be the targets of superantigen-mediated cellular cytotoxicity.

Antibodies, Monoclonal↗

Synovial fibroblasts as accessory cells for staphylococcal enterotoxin-mediated T-cell activation.

Rheumatoid arthritis (RA) is thought to be the result of T-cell-mediated autoimmune phenomena. So far, a critical autoantigen has not been identified. Recently, superantigens have been implied in the pathogenesis of RA. In the present study it was tested whether major histocompatibility complex (MHC) class II-positive synovial fibroblast cells (SFC) function as superantigen-presenting cells. SFC were stimulated with interferon-gamma (IFN-gamma) to express class II antigens; then they were cultivated in the presence of T cells with or without staphylococcal enterotoxins (SE). T-cell activation was measured as proliferation and interleukin-2 (IL-2) production. Depending on the dose and type of SE, activation of T-cell clones and also of peripheral T cells was seen. T-cell activation was inhibited by antibodies to MHC class II antigens and also by antibodies to intracellular adhesion molecule type-1 (ICAM-1). The data suggest that class II-positive SFC have the capacity to serve as accessory cells for superantigen-mediated T-cell activation. Thus SFC may participate in the propagation of a T-cell dependent immune response.

Antigen-Presenting Cells↗

[Virtual reality in medicine].

The methods of virtual reality (VR) will come to play a routine part in the work of hospitals. It is difficult to understand and explain what VR means in medicine and its scope in medicine. This paper distinguishes the four functional categories of Immersive VR, Desktop VR, Pseudo VR and Inverse VR. Immersive VR uses a head-mounted display and data gloves as input devices, while Desktop VR uses VR shutter glasses and a 3D input device such as the 3D mouse. Pseudo VR comprises interactive controllable animation. Inverse VR uses, for example, biosignals as an input device in order to support the computer user in the real world. This paper discusses the potential applications of the four categories of VR in medicine with reference to topical projects.

Computer Graphics↗

Interaction of the terminal complement components C5b-9 with synovial fibroblasts: binding to the membrane surface leads to increased levels in collagenase-specific mRNA.

The late complement components, apart from their lytic function, are known to trigger the release of various proinflammatory substances from different types of nucleated cells. In the present study, the interaction of C5b-9 with synovial fibroblast cells (SFC) was examined. It was found that incubation of SFC with activated complement components resulted in binding of C5b-9 to the cell membrane; subsequently an increase in abundance of collagenase-specific mRNA was seen, as assessed by Northern blotting. When C8-deficient serum was used as source of complement neither binding of C5b-9 nor an increase in collagenase-specific mRNA could be detected. These findings suggest that C5b-9, which might be generated during rheumatoid inflammation, may contribute to chronic joint destruction by triggering collagenolytic activity.

Arthritis, Rheumatoid↗

Does in vitro colony formation and chemosensitivity relate to DNA ploidy and S-phase fractions?

In vitro colony formation and chemosensitivity were analyzed in 65 human solid tumors and compared to proliferation parameters simultaneously obtained by DNA flow cytometry of the same tumor specimens. Colony growth in the human tumor colony assay was enhanced in aneuploid tumors (39/65) in comparison to diploid tumors (26/65, P less than 0.05). In addition, there was a relationship between % S-phase and colony growth. The existence of polyploid sublines (23/65) improved in vitro growth even in tumors with a diploid main G0/1-peak or with a low % S-phase. Metastases exhibited a higher proportion of aneuploidy and showed slightly better growth in vitro than primary tumors. Sensitivity testing in 34 of the 65 tumors showed no convincing relation between DNA parameters and the inhibition of colony formation by five standard anticancer agents with different mechanisms of action. This indicates additional factors other than the proliferative activity of the tumor to be responsible for drug sensitivity or resistance.

Antineoplastic Agents↗

Stereology of myocardial hypertrophy induced by physical exercise.

Twenty young female Sprague-Dawley rats were randomly assigned to 2 groups. Ten animals served as sedentary controls, the 10 experimental animals were subjected to a training program with gradually increasing intensity of 18 weeks duration on a motor-driven treadmill. The rats were fixed by retrograde vascular perfusion via the abdominal aorta under anesthesia. Two transverse and 2 longitudinal sections per animal were selected at random from the left ventricular papillary muscles for light and electron microscopic stereological investigation. Length density and surface density of myocardial cells and capillaries were estimated with correction for partial anisotropy and curvature by means of the mathematical model of a Dimroth Watson orientation distribution. Left and right ventricular weight increased by 20% in the exercise group (P less than 0.001), whereas body weight remained unchanged. Physical training led to a significant increase of heart muscle fiber cross-sectional area by 17% (P less than 0.01). The ultrastructural volumetric composition of the myocardial cell cytoplasm by myofibrils, mitochondria, and sarcoplasmic matrix remained unchanged. Volume density, length density and surface density of capillaries, as well as capillary cross-sectional area and capillary anisotropy parameters were not significantly altered by training. From the data one concludes an increase of the 3-dimensional capillary-fiber ratio by 19% (P less than 0.001). Thus physical training induces mild absolute biventricular cardiac hypertrophy in young female rats, in which capillary proliferation compensates for the increase of mean oxygen diffusion distance resulting from fiber thickening, by supplying each unit of fiber length by more units of capillary length.

Animals↗

[DNA measurement of malignant tumors by impulse cytophotometry. The principles and importance for assessing growth behavior and the degree of abnormality].

Monometric DNA impulse cytophotometry of ploidism state (diploid or aneuploid tumors with stemmline shift, polyploidism ) and proportion of DNA-synthesized cells (S-phase proportion) were determined on over 500, mostly malignant, tumors of different sites. The results were compared with histopathological findings (TNM stage and degree of differentiation). Large diploid carcinomas of the oral cavity have lower S-phase activity than aneuploid tumors. Carcinomas of the breast, stomach and ovary are frequently diploid. Aneuploid carcinomas of these regions generally have high synthesizing activity. Mucoid signet-ring carcinomas of the stomach have lower S-phase activity than non-mucoid carcinomas. In the colorectal region aneuploid carcinoma predominates, in the colon more than in the rectum. Tumor metastases from colon and rectum into the liver predominantly are from aneuploid primary tumors. For tumors of the breast, corpus uteri and ovary with high and moderate differentiation there is a direct correlation between histological grade of differentiation and the S-phase proportions. Aneuploid tumors vary from low to high synthesizing activity. Diploid meningioma and glioma have a low S-phase proportion, aneuploidism correlates with an increase in growth. Supplementation of histopathological diagnosis by determining ploidism and S-phase activity makes an important contribution in the assessment of the degree of malignancy, as well as for therapeutic purposes.

Aneuploidy↗

Hot melt "corner point method" for attaching large plastic sections to glass slides.

We describe a fast method for firm attachment of large plastic sections to glass slides with EVA-copolymers, commonly known as hot melt sticks. Solid hot melt sticks dissolve slowly in xylene to form an adhesive gel within 6 hours. Small drops of hot melt gel are applied to the corners of the sections and surrounding slide surface at ambient or elevated temperatures. The gel sticks to both the plastic and the glass slides. The hot melt "corner point method" prevented detachment of sections in staining procedures. As an additional technique, we suggest the use of hot melt adhesive for attaching plastic specimen blocks to wooden blocks or metallic specimen holders.

Adhesives↗

[Orthopedics in the world wide web: university homepages of the G-7 states].

QUESTIONS: By which criteria can a homepage be evaluated? How is the quality of homepages provided by universities in the field of orthopaedics/traumatology? METHODS: Based on 37 ranking instruments, an optimized list of criteria has been developed. Homepages of orthopaedic and traumatology departments of medical schools in the G7 Nations have been found with help of university homepages and search engines and afterwards were analysed according to previously defined criteria. RESULTS: A list of criteria containing 18 subject areas with 49 questions was developed. 136 homepages were evaluated from October 1998 to April 1999. 15 outstanding homepages were found. The best homepages are from medical schools in the USA and Germany. The most frequent subjects were structure of the department (contained in 85% of the homepages) and education/training (68%). 42 homepages provided medical information, 67% of those homepages provided references (attribution), and 26% provided information about authority and authorship. 46% of all hompages were not updated sufficiently. Out of 125 homepages with an e-mail address 36% responded to an inquiry. Multimedia features such as video, sound or animation were used by 6% of the homepages. CONCLUSION: Apart from few exceptions, homepages of orthopaedic-traumatologic departments of medical schools are still insufficient with regard to quality and quantity, especially regarding medical information for patients and professionals. The developed last of criteria should be helpful in installing a basic standard for homepage quality. The time and effort involved in setting up and servicing a homepage should not be underestimated.

Cross-Cultural Comparison↗