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Biomedical subjects

G Bendixen

Publications and source records attributed to G Bendixen.

At least 55 records · Page 3Linked to original sources

Discussion paper: tumor-directed cellular hypersensitivity detected by leucocyte migration in patients with renal carcinoma.

Leucocyte migration inhibition detected in vitro by the capillary tube technique (LMCT) has proved a useful tool for detection of tumor-specific cell-mediated hypersensitivity (TCMH) in man. Investigations in pateints with renal tumors are reported. It is shown that TCMH is a feature of hypernephroma in man, that the antigenic specificity is found in autologous as well as allogeneic tumor tissue and in fetal kidney tissue. The pattern of reactivity compared to postoperative survival and occurrence of metastases and postoperative clinical course shows a clear association between TCMH and tumor elimination. The capacity of hypernephroma patients to develop a cell-mediated immune response is generally not reduced. In allogeneic combinations, small noninvading tumors usually have a high antigenicity, whereas tumors with early dispersion show a low antigenicity. The development of TCMH and associated tumor elimination therefore may be depending preferably on the antigenicity of the tumor, less on the immune capacity of the tumor host.

Adenocarcinoma

Immunological studies in sarcoidosis: a comparison of disease activity and various immunological parameters.

We found it valuable to separate the heterogeneous types of sarcoidosis into more homogeneous groups on the basis of activity and duration of the disease. This view is supported in the present study by the finding of a marked depression of T-cell function in patients with chronic-active sarcoidosis. Patients with acute or chronic-inactive disease had only moderately depressed T-cell function as measured by tuberculin skin test and DNCB index. These results are in agreement with those of some previous investigations. The remainder of the abnormal findings, particularly low total number of circulation T lymphocytes, elevated serum IgG levels, and presence of autoantibodies, could not be correlated to disease activity, extent of the disease, or T-cell function. We have found no explanation for the presence of autoantibodies but suspect that they may be nonspecifically related to the disease process.

Adolescent

Morphology of experimental, organ-specific insulitis of the mouse pancreas.

The morphologic and metabolic effect of a single intracutaneous injection of homologous endocrine pancreas in Freund's complete adjuvant (CFA) was studied in 100 mice and compared with control groups which had been (1) immunized with murine insulin in CFA, (2) injected with CFA alone, or had (3) received no treatment. There were no differences between the control groups as regards the morphology of the pancreatic islets, and the glucose tolerance was normal. Mice immunized with islet homogenate exhibited morphological changes in the form of degranulation and cytoplasmic disintegration. These changes involved B-cells as well as A2-cells and were present from 7 to 18 days after the immunization. A significant reduction in glucose tolerance was observed 14 days after the immunization. Another characteristic finding in the islets from the immunized mice was the extra-vascular presence of mononuclear, agranular cells which on the basis of their morphological criteria appeared to represent lymphocytes.

Animals

Immunopathogenic mechanisms in tissue damage.

Our knowledge on immunopathogenic damage is derived from multiple different sources: experiments in vitro, experiments in vivo, clinical observations, and observations using material from multiple different animal species including man. If we want to analyse an immunological process suspected of causing tissue damage we have critically to evaluate the mechanism of immunologically specific initiating factors and the mechanisms of non-specific mediating factors. It is necessary to have clear information on the identity of the antigen, the location of the antigen, the identity of antibody, the location of antibody and similar information on specifically reactive lymphocytes. With this information in mind it is possible to hypothesize upon mechanisms, which can be responsible for the immunologically specific initiation of immuno-pathogenic damage. The non-specific mediating systems, which are the actual inducers of functional or structural tissue damage, are triggered by the specific, initial immune reaction. These systems comprise for instance complement, coagulation, granulocyte and macrophage lysozomes and function, chemotaxis, the mast cell system, phagocytosis etc. The overall picture of non-specific mediation of tissue damage is extremely complex, since it really makes it necessary to investigate and describe not only these systems but also their co-existence and interaction. Knowledge of immunopathogenic mechanisms in clinical disorders in man is still resting mainly upon analogies and assumptions, although progress is taking place. It is essential to ask the right questions and critically to evaluate the answers. Thereby the understanding of immunopathogenesis in diabetes mellitus and other clinical disorders shall gradually improve.

Animals

Leucocyte migration inhibitory activity (LMIA) on concanavalin A (Con-A) stimulated human lymphocytes. Comparison of leucocyte migration capillary technique (LMCT), leucocyte migration agarose technique (LMAT), and leucocyte migration fibrinolysis technique (LMFT).

Leucocyte migration and migration inhibition in fibrin medium may reveal new aspects of lymphokine activity associated with immunological inflammation. Leucocyte migration fibrinolysis technique is compared with the leucocyte migration capillary technique and the leucocyte migration agarose technique. In the present model experiment the three methods gave comparable results. The leucocyte migration fibrinolysis technique involves a new principle for detection of lymphokines and can probably be developed to give more exact information about the interrelationship between thrombosis, fibrinolysis and lymphokines.

Adult

Lymphokines and thrombosis. I. Thrombocyte aggregating activity released by human lymphocytes stimulated with concanavalin-A.

Supernatants from Con-A stimulated human lymphocytes containing leucocyte migration inhibitory activity were measured for thrombocyte aggregation activity and for influence on thrombocyte rich plasma clot retraction and whole blood clot retraction. The lymphocyte released activity of the supernatants produced thrombocyte aggregation and an acceleration of clot retraction. The activity resisted heating at 56 degrees C for 30 min and was inactivated at 80 degrees C for 30 min. The active substance seems to have a molecular weight above 10,000 daltons. The findings suggest that thrombotic processes associated with cell-mediated (type IV) immune inflammation could be due, at least partially, to lymphokine effects on thrombocytes.

Blood Platelets

Cell-mediated immunity to a serologically defined (SD) HL-A antigen panel in kidney-transplanted patients.

The graft-directed, cell-mediated immunity in kidney-allografted patients was examined with a seriologically defined (SD), donor-unrelated panel of antigenic material in clinical steady state, soon after transplantation, and during acute rejection episodes. The SD antigens were selected from the panel on the basis of predictions hypothesized from the SD match of donor and recipient. The cell-mediated immunity was measured by the direct leukocyte migration agarose test (LMAT). Positive reactions in kidney-transplanted patients were induced particularly by one preparation (antigen 52) and were unpredictable on the basis of SD classification. The investigation shows that other antigenic determinants, different from SD antigens, probably play an important role as inducers of cell-mediated, graft-associated immunity in kidney-transplanted patients.

Adult

An in vitro assay of leukocyte migration inhibitory activity from human lymphocytes stimulated with concanavalin A.

Human venous blood lymphocytes, incubated for 22 h in serum-free culture medium with the plant mitogen concanavalin A (Con-A), elaborated products, which inhibited the migration of human buffy coat cells under agarose. Con-A was removed by applying the supernatants on small Sephadex G-100 columns. The leukocyte migration inhibitory activity (LMIA) was tested in a semi-quantitative modification of the indirect leukocyte migration agarose technique, which is described. Lymphokine activity, demonstrable as early as 9 h after activation of lymphocytes, was most pronounced after 22 h. Significant LMIA was demonstrated in 12 of 17 normal individuals at standard dilution of culture supernatants I/3. In 9 of the 12 experiments, assays of LMIA were carried out on stepwise diluted supernatants with detection of the greatest dilution with significant LMIA. In four experiments LMIA could only be detected after 3- to 12-fold concentrations of supernatants. Considerable individual variation was found, the amounts of LMIA varying by a factor of about 300. The reproducibility appeared to be quite high, but the factor stability of supernatants stored at -20 degrees C was surprisingly low.

Adult