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Biomedical subjects

H Ambrosius

Publications and source records attributed to H Ambrosius.

At least 19 recordsLinked to original sources
PubMed1991

The MTT-assay as a rapid test for cell proliferation and cell killing: application to human peripheral blood lymphocytes (PBL).

The possibility to use the colorimetric MTT assay for measuring proliferation and cell death of human peripheral blood lymphocytes (PBL) was studied. In a range from 100,000-800,000 cells/well a linear correlation between the optical signal (OD signal at 570 nm) and the cell number was found. It is necessary to incubate the cells with the MTT at least 2 hours. After stimulation by different PHA concentrations a very good correlation between [3H] thymidine incorporation and MTT assay was found. A comparison of daunomycin cytotoxicity, measurement by trypan blue exclusion and MTT assay, gave also a good correlation between both methods. It can be pronounced that the MTT assay is a suitable method to measure cell proliferation and cell death of human PBL. The assay is easy to handle, a large number of probes can be assayed in a relatively short time and no radioactivity is necessary. For the measurement of the colored product a common ELISA reader can be used.

Cell Death↗
PubMed1991

[Quantitation of Acinetobacter calcoaceticus in mixed bacterial cultures by an enzyme immunoassay].

An enzyme-linked immunosorbent assay using polyclonal antibodies from rabbits has been developed for quantification of Acinetobacter calcoaceticus. Bacteria were added to the wells of a microtiter plate coated with anti-Acinetobacter immunoglobulin. For detecting bound cells the peroxidase-labelled immunoglobulin fraction was used. Over a distinct range there is a linear correlation between bound bacteria and measured absorbance allowing a quantification of bacteria in an order from 10(7) to 10(8) per milliliter. The specificity of the assay was evaluated by the heterologous bacteria Pseudomonas putida, Pseudomonas aeruginosa, Proteus vulgaris, Escherichia coli and Citrobacter freundii. Only a minimal cross-reactivity was observed. Within a certain range of error it is possible to quantitate Acinetobacter calcoaceticus in mixtures with one or several other bacterial species. Mixed with bacteria of one other species the differences to the value for Acinetobacter calcoaceticus alone do not exceed +/- 10% with a tendency to lower values. Mixed with several other species only negative differences up to -15% were obtained. Treatment of Acinetobacter calcoaceticus with 0.5% formaldehyde results in a loss of reactivity up to 15%. In conclusion, the enzyme-linked immunosorbent assay is a useful method for quantitating bacteria not only with respect to the high sensitivity, specificity and good reproducibility but also for the minimal technical equipment and the short assay time.

Acinetobacter calcoaceticus↗
PubMed1990

Culture and stimulation of human T- and B-lymphocytes.

The cultivation and stimulation of human peripheral blood cells by different mitogens were studied using a serum-free culture technique. It shows the possibility to culture human PBL in a commercially available serum-free medium over a period of at least 7 days. In a serum-free medium with high protein content the viability of the cells was higher than in one with low protein content or in a serum containing medium. It is possible to stimulate human T cells by phytohaemagglutinin in a serum-free medium. After measurement of [3H]thymidine incorporation, a significant difference between control and test cultures was found. There is also a difference between serum-free medium with high and low protein content. Human peripheral B lymphocytes stimulated by pokeweed mitogen did not show any measurable IgG-secretion if they were cultured in serum-free medium.

B-Lymphocytes↗
PubMed1990

[Immunoenzyme assay of parasite-specific IgG4 antibodies in schistosomiasis using the monoclonal antibody BL-IgG4/1].

Sera from 251 children living in endemic areas (Schistosoma mansoni or Schistosoma haematobium) and from 188 hospital outpatients in Ethiopia were evaluated for specific IgG4 antibodies reacting with Schistosoma mansoni adult worm antigen employing an enzyme-immunoassay. Patients with schistosomiasis (n = 140) possessed a significantly higher mean value of specific IgG4 antibodies than normal controls (n = 30) and individuals from different countries who had no schistosomiasis but are infected with other parasites (n = 114). Blood samples dried on filter paper were also acceptable in these test. The use of the test in diagnosis is compared and assessed with parasitological methods.

Animals↗
PubMed1990

[Effect of Schistosoma mansoni infection on the immune reactions against heterologous antigens in mice].

Mice (BALB/c or ICR) were infected with Schistosoma mansoni cercariae. After different intervals (mostly eight weeks) the following antigens were injected: a) sheep erythrocytes--b) DNP-thyroglobulin. Afterwards the immune response against these antigens were checked by means of different methods (plaque assay, haemagglutination test, rosette technique). Immune responses to these antigens were depressed in all cases compared to age matched uninfected mice but it was not possible to transfer this immunosuppression with spleen cells to normal or to irradiated recipients.

Animals↗
PubMed1990

[The importance of the endogenous agent and environmental factor thiocyanate for nonspecific and specific resistance from the hygienic viewpoint].

Thiocyanate (previous designation rhodanide, SCN-) is a physiological substance which is ubiquitously spread in the animate nature. As an essential constituent of cell it participates in important physiological resp. biochemical processes. From the hygienic and microbiological point of view the occurrence of SCN- as environmental factor, its alimentary significance and its vitalizing effect (stimulation of nonspecific and specific warding off, stimulation of proliferation, protective effect at toxic loading) are of interest for the fundamental and applied research.

Animals↗
PubMed1990

[Initial experiences in diagnosis of graft rejection following clinical heart transplantation. Detection of graft-directed activated T-cells].

The binding of antigen-loaded carrier to mononuclear cells of heart transplant recipients has been investigated by means of an antigen-specific rosette technique. The increase of rosette forming cells and the inhibition of this reaction with monoclonal antibodies against activated T-cells is a sign of a beginning rejection. 3-6 days later infiltrating immunological competent cells are seen in biopsy.

Adult↗
PubMed1989

Surface immunoglobulin on lymphocytes of the tortoise Agrionemys horsfieldii.

Surface immunoglobulin bearing (sIg+) cells were identified in the tortoise Agrionemys horsfieldii by indirect immunofluorescence by using class-specific antisera to tortoise IgM and IgY produced in mice. With this technique 13-23% of blood lymphocytes were found to bear surface IgM and 5-8% IgY. Spleen lymphocytes show a higher percentage of sIg+ cells: 25-52% sIgM+ and 5-20% sIgY+ lymphocytes. There is strong indication that tortoise sIgY+ lymphocytes of blood and spleen also express IgM on their surface.

Animals↗
PubMed1989

Immunohistochemical characterization of lymphocyte populations in carp (Cyprinus carpio L.).

Surface immunoglobulin-bearing cells from peripheral blood, thymus, head kidney, and spleen in carp (Cyprinus carpio L.) were studied by immunoperoxidase labelling using antisera against fragments of carp IgM. Different lymphoid cell populations could be determined. Thus, about 35% of the lymphocytes of the peripheral blood, head kidney, and spleen were determined, as "B" lymphocytes, using rabbit anti-carp Fab antiserum with L chain specificity. Nearly all lymphocytes of the peripheral blood, head kidney, and spleen are bearing immunoglobulin determinants or cross-reactive structures. The latter also holds true for about 98% of thymocytes. The differences between the Ig-like surface structures of the thymocytes and the membrane-bound immunoglobulins of a population of lymphocytes are discussed.

Animals↗
PubMed1988

Comparative studies on the structure of biliary immunoglobulins of some avian species. II. Antigenic properties of the biliary immunoglobulins of chicken, turkey, duck and goose.

Studies on the immunological cross-reactivity of the Igs+ from the bile of chicken and turkey (order Galliformes) as well as duck and goose (order Anseriformes) to Igs with antigenic known properties carried out by a series of RIA. Various class-specific anti-Ig sera produced in rabbits, guinea-pigs and mice were used. The following results were obtained: (1) A high extent of antigenic relationship between the chicken and turkey biliary Igs was demonstrated by a radiobinding system consisting of 125I-turkey biliary Ig and class-specific rabbit anti-turkey biliary Ig antibodies. The biliary Igs of duck and goose did not inhibit this antigen binding system. (2) The duck and goose biliary Igs were able to inhibit the binding of 125I-carp IgM to Fc-fragment-specific rabbit anti-carp IgM antibodies and of 125I-human IgM to Fc-fragment-specific guinea-pig anti-human IgM antibodies, respectively. (3) None of the biliary Igs show cross-reactive properties common with human and porcine IgA. That was detected by inhibition of the radio-binding system from 125I-human IgA and alpha chain-specific mouse anti-human IgA antibodies. Therefore, the conclusion was made that in anseriform birds IgM-like Igs are the secretory Igs, while in galiform birds biliary Igs with special antigenic properties occur.

Animals↗
PubMed1988

Comparative studies on the structure of biliary immunoglobulins of some avian species. I. Physico-chemical properties of biliary immunoglobulins of chicken, turkey, duck and goose.

In pooled bile of chicken, turkey, duck and goose immunoglobulins (Igs)+ were found in relatively high amounts between 4.5 and 15.0 mg/ml (corresponding to 28 to 36% of the total protein contents). All biliary Ig fractions studied possess (H2L2)n structure estimated by SDS-PAGE. In chicken and turkey L chains are assumed to be non-covalently linked to the polymeric H chains. In duck and goose L chains are completely linked to H chains. The Mr of H chains are rather similar: 64 kDa for the Igs of chicken and turkey bile and 67 kDa for the biliary Igs of duck and goose. There are slight differences in the electrophoretic mobility: Chicken and turkey Igs are beta 1/alpha 2-globulins and the corresponding Ig fractions from duck and goose are beta 2-globulins.

Animals↗
PubMed1988

The immune response of carp against dextran. An analysis of the idiotype heterogeneity.

The expression of a "species-specific" idiotype with specificity for alpha(1-6) dextran in carp is described. All tested carp anti-dextran antisera react with a rabbit anti-Id (carp anti-dex) serum. The rabbit anti-Id serum can be partially inhibited by the specific ligand, dextran T70 or isomaltodecaose but not or only weak with other, unrelated carbohydrates. These data confirm our statement, that a limited germline V-gene repertoire may code for antibodies in fish.

Animals↗
PubMed1988

Anti-dextran antibodies of carp detected by the enzyme-linked immunosorbent assay (ELISA).

Carp produce anti-alpha (1-6) dextran antibodies after immunization with a vaccine of Leuconostoc mesenteroides B512. These antibodies can be determined by passive haemagglutination, quantitative precipitation or by ELISA. In our hands the ELISA has proved to be 100 times more sensitive than the passive haemagglutination test. We could not found any correlation between the anti-dextran activity estimated with the passive haemagglutination on the one and the ELISA on the other hand.

Animals↗
PubMed1987

Immune response of carps (Cyprinus carpio L.) against dextran.

In carps no antibodies could be evoked by immunization with soluble high molecular weight dextran using doses of 1-5000 mg dextran per kg body weight. On the other hand, an immune response against dextran could be elicited by immunization with a vaccine of Leuconostoc mesenteroides B512 as well as a dextran-BSA-conjugate. These carp anti-dextran antibodies showed precipitating and agglutinating activities with specificity against alpha linked dextran determined by the almost complete inhibition of the dextran-anti-dextran reaction by isomaltodecaose.

Animals↗
PubMed1987

Sepharose gels as antigenic matrices for specific binding of anti-galactosyl antibodies.

From 100 ml of pooled normal serum taken from different species (man, cow, rabbit, chicken, duck, carp) 0.5 to 4.0 mg of high and low molecular weight anti-galactosyl antibodies could be isolated by affinity-chromatography on non-ligand-attached Sepharose 4B. The antibodies bound to the agarose matrix were eluted with 0.5 M D-galactose containing buffers. Using species-specific anti-immunoglobulin sera in immunoelectrophoresis, the immunoglobulin character of the protein fractions prepared was analyzed. In addition, the H and L chain structure of the anti-galactosyl antibodies was checked by SDS-PAGE.

Animals↗