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Biomedical subjects

W Knapp

Publications and source records attributed to W Knapp.

At least 271 records · Page 15Linked to original sources
PubMed1975

[Heterologous fibrinogen for tissue adhesion. immunological and histological investigations (author's transl)].

The immunological reactions of heterologous fibrin were investigated in a sensitive experimental system. In 10 rabbits autologous full-thickness skin grafts were glued with bovine fibrinogen cryoprecipitate. 5 of these animals had been immunized against this adhesive before transplantation. In a control group the graft was fixed with homologous fibrinogen cryoprecipitate. Examination of the sera of the animals for antibodies against fibrinogen was performed before immunization, 1 day prior to and 14 days after skin grafting. 14 days after skin adhesion all grafted areas were examined by histological methods. In the group without preoperative immunization antibodies were found against fibrinogen. The skin graft healed in this series in the same manner as in the sham group. In the series with preoperative immunization the glued skin graft was discharged early and the healing procedure of the defect was retarded.

Animals↗
PubMed1975

[Kinetoplast of the flagellate crithidia luciliae: a suitable substrate for the detection of antibodies to native, double-stranded DNA in the indirect immuno-fluorescence test (author's transl)].

Sera from 29 patients with systemic lupus erythematosus (SLE), 60 cases of rheumatoid arthritis, 34 of myasthenia gravis (MG), 10 of scleroderma and 20 control sera were investigated for the occurrence of antibodies to native, double-stranded (ds) deoxyribonucleic acid (DNA). An immunofluorescence procedure recently elaborated by Aarden and coworkers, which utilizes the kinetoplast of the hemoflagellate Crithidia luciliae as substrate, was employed. In this kinetoplast, native, ds-DNA is concentrated as a single large network. Antibodies reacting with kinetoplasts were restricted to the SLE group, with the exception of one MG serum which also exhibited a distinct kinetoplast fluorescence. The antibody activity of the SLE sera could be completely inhibited by small amounts of DNA and abolished by deoxyribonuclease treatment of the substrate. These findings underline the specificity of the test system for anti-ds-DNA antibodies and the high disease-specificity of these antibodies for SLE. With respect to its ease and speed of performance this highly reliable and specific flagellate test surpasses other known tests for the detection of anti-ds-DNA antibodies.

Antibodies, Antinuclear↗
PubMed1975

Microfluorometric evaluation of conjugate-specificity with the defined antigen substrate spheres (DASS) system.

Six fluorescent antihuman Ig preparations were tested for their Ig class specificity by reacting them with highly purified IgG, IgM, IgA, and OVA coupled covalently to Sepharose beads. OVA was used as a measure for nonimmunologic binding. Bead fluorescence was determined by microfluorometry. The amounts of USS and NSS were expressed quantitatively. These data were compared with the performance of these particular conjugates in a biologic system, namely, monoclonal bone marrow cells. Five of the six conjugates satisfied the requirement of monospecific activity; one did not. At a dilution of 1 : 8, the five monospecific conjugates reacted between five and 50 times stronger with their appropriate antigens than with OVA-coupled beads. Cross reactivity with other Ig classes, after correction for OVA staining was maximally 6%. The conjugate that was nonspecific in the bone marrow system gave very high cross reactivity with the Ig-coupled beads. A good correlation was found between OVA bead staining and nonimmunologic binding of conjugates in bone marrow slides. In this respect, conjugates prepared from antibody preparations isolated by solid immunoadsorbents proved to be superior to globulin or whole IgG fractions. Ig coupled to Sepharose beads seems to represent a very promising substrate for conjugate specificity testing.

Adsorption↗
PubMed1975

Differentiation of lymphoid cells of the B cell series according to membrane and cytoplasmic determinants.

Previous investigations have shown that a large proportion of normal human lymphocytes bearing membrane-bound IgM have also independently moving IgD molecules on their surface. Since it is known that in the majority of chronic lymphatic leukaemias (CLL) high numbers of lymphocytes with easily detectable membrane IgM can be found, we investigated CLL cells for the presence of membrane-bound IgD. In all 18 cases studied, high proportions of cells bearing surface IgD and IgM could be found. In none of the 18 cases crystalline Ig inclusions could be detected.

B-Lymphocytes↗
PubMed1975

[Immunologic types of lymphocytes in acute lymphatic leukemia during remission (author's transl)].

The rates of B and T-cell-subpopulations of lymphocytes were examined on 15 children with acute lymphatic leukemia during the first complete remission under maintenance in the Pinkel VII scheme and in 6 further cases with modification of this scheme of treatment compared to normal children in the same age groups. Further on 4 children during a relapse, on 1 during the second remission, and on 3 during long-term remissions. The most important result was a significant reduction of B cells during intensive maintenance therapy of the Pinkel scheme. In the few cases of long-term remissions a reduction of B cells was no longer observed.

Adolescent↗
PubMed1975

On the sugar content of the lipopolysaccharides of the various strains known as Yersinia enterocolitica.

With a single exception among 11 strains, each strain of Y. enterocolitica representing one of the six O-groups possesses, as judged by the sugar composition of its lipopolysaccharides, a particular chemotype. All 14 of the strains examined possessed glucosamine, KDO, two heptoses and glucose. In the most complicated chemotype 10 sugars were demonstrable. Of three Y. enterocolitica strains not included in the 6 O-groups, two had the same chemotype as the representatives of the O-groups IV and VI. Details can be seen in the two tables.

Animals↗
PubMed1975

Interactions of the third component of complement (C3) with cross-linked dextran. III. Isolation and characterization of interacting components after enzymatic digestion of complement coated cross-linked dextran.

In previous investigations we could show that incubation of cross-linked dextran (Sephadex) with normal human and normal guinea pig serum results in the binding of C3 to Sephadex. This binding was found to be due to activation of C3 via an alternate pathway. In this paper data are presented which show that components bound to Sephadex can be recovered after enzymatic digestion of serum-reacted Sephadex beads. The digests were characterized with immuno-electrophoresis and double immunodiffusion techniques. It could be shown that the main component present in the digest was converted C3. Apart from C3 under our test conditions only minute amounts of C3A but no other serum proteins were detectable. The observation that almost exclusively C3 is bound to Sephadex is further supported by the finding that immunization of rabbits with serum-reacted Sephadex beads results in the exclusive formation of anti C3 antibodies. Implications from these findings and possible applications are discussed.

Antibody Formation↗
PubMed1975

Interactions of the third component of complement (C3) with cross-linked dextran. IV. Adherence of lymphocytes to C3 coated dextran gel particles.

In previous studies we could show that the third component of complement (C3) is bound from normal serum to cross-linked dextran (Sephadex) after activation via an alternate pathway. Data presented in this paper demonstrate that a subpopulation of human lymphocytes adheries to C3 coated Sephadex particles. The adhering subpopulation of lymphocytes is identical with or overlaps extensively with lymphocytes bearing easily detectable membrane Ig. This phenomenon can be used for the fractionation of lymphocyte subpopulations. After a single passage of tonsillar lymphocytes through C3 coated Sephadex bead columns, no membrane Ig positive lymphocytes were detectable in the effluent. 97-100% of effluent cells formed rosettes with untreated sheep red blood cells, thus resembling pure T cells. Apart from that, the use of C3 coated dextran gel particles allows also the recovery of adherent cells after dextranase digestion of the dextran gel particles. An investigation of retained cells showed enrichment of B cells, but also T cells were demonstrable. The retention of these T cells is probably due to nonspecific interactions.

Cell Separation↗
PubMed1975

Interactions of the third component of complement (C3) with cross-linked dextran. II. Demonstration of an alternate pathway activation as binding mechanism of C3 to cross-linked dextran.

In previous investigations we could show that incubation of cross-linked dextran (Sephadex) with normal human serum results in the binding of the third component of complement to the Sephadex beads. In this paper, data are presented which demonstrate that not only human but also guinea pig C3 reacts with Sephadex and that this binding is due to an alternate pathway of C3 activation. This conclusion was drawn, since a) C3 is bound also from guinea pig serum with total deficiency of C4, b) the reaction can be completely blocked by EDTA but only diminished by EGTA and c) the reaction turned out to be temperature dependent with an optimum at 37 degrees C and could be abolished by diluting the serum more than 1:16. The ability of cross-linked dextran to activate C3 via the alternate pathway seems to be due to conformational changes, since in our experiments soluble dextran of the same source was found to be ineffective in this respect. Implications from these findings and possible applications are discussed.

Animals↗