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Biomedical subjects

A Bauer

Publications and source records attributed to A Bauer.

At least 217 records · Page 12Linked to original sources
PubMed1990

[Institutional establishment of pathologic anatomy in the 19th century at universities in Germany, German-speaking Switzerland and Austria].

The institutionalization of an academic discipline in the university system is a complex process influenced by several intra- and extrascientific, personal and economic factors. Starting with pathological anatomy at the beginning of the 19th century, we analysed its development from a subsidiary to a fully established discipline. We ascertained different stages of institutionalization:lectureship, associate chair, chair, institute. At each stage we found supporting as well as hindering factors. It could be shown that the structure of the German academic system was especially conductive to the establishment of the new discipline.

Austria↗
PubMed1989

Role of interleukin 1 in mycoplasma mitogen-induced proliferation of human T cells.

Recently, a mitogenic effect of the supernatant of cultured mycoplasma arthritidis (MAS) on human and murine lymphocytes has been described. Here, we studied the role of accessory cells (AC) in MAS-induced T cell proliferation in a system of human leukocytes. Nylon-wool purified T cells were non-responsive to MAS with regard to both proliferation and IFN-gamma production. The capacity of T lymphocytes to respond to MAS could be restored when viable AC were added. Treatment of AC with UV light resulted in a cell population which was incapable of reconstituting T cells. Addition of human recombinant interleukin 1 alpha (IL 1 alpha) or IL 1 beta again showed a reconstituting effect. However, only a partial reconstitution of the T cell response could be achieved by addition of recombinant IL 1 alpha or IL 1 beta. The optimal restoration was achieved by adding IL 1 at a concentration of 100 U/ml IL 1 alpha or 100 U/ml IL 1 beta. The results indicate that metabolically active AC were required for MAS-induced T cell proliferation to occur and that IL 1 was able to substitute for the role of AC. Since this restoration was only partial, it remains to be determined whether factors others than IL 1 are required to fully substitute the role of accessory cells.

Antigen-Presenting Cells↗
PubMed1989

A prototype gas exchange monitor for exercise stress testing aboard NASA Space Station.

A monitor was developed to track weightlessness deconditioning aboard the National Aeronautics and Space Administration (NASA) Space Station by measuring the O2 uptake (VO2) and CO2 production (VCO2) and calculating maximum VO2 and anaerobic threshold during an exercise stress test. The system uses two flowmeters in series to achieve a completely automatic flow calibration, and it uses breath-by-breath compensation for sample line transport delay. The accuracy of the system was measured over the range of VO2 and VCO2 from 100 to 800 ml/min by means of simulation. Accuracy was 0.54% for VO2 and 2.9% for VCO2. The system was further evaluated using two laboratory methods, the first method being comparison with a breath-by-breath system. As volunteers performed a maximum effort on a cycle ergometer, the mean difference in readings between the two systems was 17 ml/min for VO2 and 8.0 ml/min for VCO2. The correlation coefficient squared was greater than 0.96 for both. The second laboratory test was to use the system for 2 mo in a Human Performance Laboratory. Readings of maximum VO2 (VO2max) and anaerobic threshold were repeatable and consistent with the individual's activity level. The accuracy and convenience of operation will make this a valuable instrument aboard the Space Station.

Equipment Design↗
PubMed1989

[An immunoenzyme method of determining serum levels of anti-microsomal antibodies].

Content of microsomal antigen and thyroid peroxidase activity have been compared in preparations of thyroid microsomal membranes obtained by three different methods following thyroidectomy performed because of Graves' disease or nontoxic goiter. It was demonstrated that the microsomal membrane preparations originating from the thyroid tissue obtained following operation of goiter in Graves' disease are characterized by several times bigger content of microsomal antigen than those obtained after operation of nontoxic goiter. A sensitive ELISA method has been devised for the determination of microsomal autoantibodies in blood serum. The results obtained by this methods were found to be well correlated (r = 0.67) with those obtained with RIA kits manufactured by Serono. The level of antibodies in blood serum was determined in patients with thyroid disorders and the results were compared with those obtained in a group of patients with autoimmune diseases not associated with the thyroid and in healthy blood donors. The occurrence of antimicrosomal autoantibodies was demonstrated in 90.3% of patients with untreated Grave's disease, in 89% of patients with Hashimoto disease, and in 17.7% of patients with toxic goiter. Low titre of antimicrosomal autoantibodies was found in only small percentage of patients with nontoxic goiter (7.7%) and in patients with autoimmune diseases of nonthyroid origin.

Autoantibodies↗
PubMed1988

Processing requirements for T cell activation by Mycoplasma arthritidis-derived mitogen.

Mycoplasma arthritidis produces in culture a polyclonal mitogen which is active for murine and human T lymphocytes in the presence of accessory cells (AC). We studied the requirements for processing and presentation by AC of Mycoplasma arthritidis supernatant (MAS) mitogen to human T cells. As inhibitors of AC processing, several agents were used which inhibit lysosomal function: the weak bases chloroquine and NH4Cl, the cationic ionophore monensin and the competitive protease inhibitor leupeptin. When these agents were used to inhibit processing by presenting cells and washed out before T cells were added to culture, they inhibited lymphocyte activation and, therefore, we assume that they interfered with the presentation of the mitogen. Thus, if MAS requires a processing step, it appears to involve lysosomal proteolysis which can be blocked in vitro.

Ammonium Chloride↗
PubMed1988

Quantitative receptor autoradiography in the human brain. Methodical aspects.

Quantitative receptor autoradiography on sections of the human brain raises methodical problems of which some are relevant also for studies in animal tissue, but others are unique in studies of human brain tissue. Procedures for the following methodical aspects are discussed: image analysis for quantitation of the regional distribution of receptor densities, saturation analysis on autoradiographs, influence of age and post-mortem delay and quenching of beta-radiation in brain tissue. The solutions proposed to these problems make receptor autoradiography in the human brain to a reliable method for studies of chemical neuroanatomy.

Adult↗
PubMed1988

Decrease of natural killer cell activity and monokine production in peripheral blood of patients treated with recombinant tumor necrosis factor.

Tumor necrosis factor (TNF), a protein predominantly produced by activated macrophages/monocytes, is presently available in recombinant, purified form for clinical trials. Intensive studies in many laboratories have shown that besides the tumorcytotoxic effects, TNF acts on a large array of different cells and has potent immunomodulatory activities. In a clinical phase I study, some immunologic functional parameters of blood cells from patients who received 24-hour infusions of recombinant human TNF (rhTNF) were analyzed. Natural killer (NK) cell activity, TNF production, interleukin-1 (IL-1) production and mitogen-induced proliferation were measured either in whole blood samples or in cultures of peripheral mononuclear leukocytes of the patients directly before and after rhTNF infusion. NK cell activity, TNF and IL-1 production capacity and proliferative responses to concanavalin A (Con A) were significantly reduced after rhTNF application. We conclude from these observations that rhTNF in vivo acts directly or indirectly on NK cells and monocytes by either inactivating their functional capacity or by absorbing the relevant cells to the endothelial cell layer, thus removing them from circulation.

Adult↗
PubMed1988

[Reduced suppression of gastric acid by ranitidine in severe reflux esophagitis. A pilot study].

Repeated intragastric long-term pH recordings for 24 h were conducted in 13 patients with reflux oesophagitis grade III and IV (Savary and Miller) during treatment with ranitidine 150 mg b.i.d. and 300 mg b.i.d. and omeprazole 40 mg mane (n = 5). Ranitidine led to a significantly less pronounced increase in median gastric pH in oesophagitis than in healthy controls. The magnitude of intragastric pH increase showed parallelism to symptomatic response and healing. Omeprazole increased intragastric pH above 4 for 24 h and caused rapid healing in non-responders. It is concluded that in patients with severe reflux oesophagitis ranitidine is less effective in increasing intragastric pH than in controls, whereas omeprazole reveals potent antisecretory activity accompanied by rapid healing.

Adult↗
PubMed1987

S-antigen. Adoptive transfer of experimental autoimmune uveitis following immunization with a small synthetic peptide.

Experimental autoimmune uveitis was observed following the adoptive transfer of T cell lymphocytes (T cells) from Lewis rats previously immunized with a small synthetic peptide, peptide M, which corresponds to the amino acid sequence of a well-defined region of S-antigen. Prior to adoptive transfer, the T cells were restimulated in tissue culture with peptide M. Approximately five days following the intravenous administration of restimulated T cells, a severe uveitis was documented both clinically and histopathologically. Clinically, the disease was characterized by iris hyperemia followed by anterior chamber exudates and posterior iris synechiae. Histopathologically, the photoreceptor cell layer of the retina was completely destroyed. A subretinal exudate containing mononuclear cells and polymorphonuclear leukocytes was also present. In addition, the pineal glands of animals with experimental autoimmune uveitis showed inflammatory changes characterized by a lymphocytic infiltration of the subcapsular and central region of the gland. The clinical and histopathologic features of the experimental autoimmune uveitis were similar to those that develop following the adoptive transfer of T cells from Lewis rats previously immunized with S-antigen. Our results indicate that the amino acid sequence of the region of S-antigen corresponding to peptide M represents a distinct pathogenic site with the ability to adoptively transfer disease. We comment on the significance of this finding with regard to T cell-mediated immune mechanisms in certain forms of human uveitis.

Amino Acid Sequence↗
PubMed1986

Lymphocyte activation and induction of interferon gamma in human leucocyte cultures by the mitogen in Mycoplasma arthritidis supernatant (MAS).

This report succinctly summarizes a number of experiments in which human leucocytes were activated by the mitogen in the supernatant of cultured Mycoplasma arthritidis (MAS). Lymphocytes from a large number of donors were found to be reactive when the two parameters of lymphoproliferation and of production of gamma interferon were analysed. Lymphocytes of cord blood origin were also reactive in lymphoproliferation. Their interferon production was low, but this has been established previously for mitogens in general. During the course of the studies, different batches of MAS were tested, including most recently a purified preparation. All of these were active. Removal of accessory cells adherent to nylon wool column abolished MAS reactivity, whereas it has little effect on lymphoproliferation induced by phytohaemagglutinin (PHA). MAS reactivity was also strongly reduced when monoclonal anti-HLA-DR antibodies were added to the leucocyte cultures.

Bacterial Proteins↗
PubMed1985

[Not Available].

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Germany↗
PubMed1984

[Not Available].

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Germany↗