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D Brandhorst

Publications and source records attributed to D Brandhorst.

At least 73 records · Page 4Linked to original sources
PubMed1994

Large-scale production of Ba(2+)-alginate-coated islets of Langerhans for immunoisolation.

Islet xenografts immunisolated in alginate capsules have been proposed by many groups for clinical islet transplantation. However, diffusion limitations and the total volume of microcapsules required for transplantation are, among other things, factors which have so far prevented successful clinical application. In this study, these problems have been overcome by immobilisation of rat and porcine islets in a Ba(2+)-cross-linked alignate matrix using an air jet droplet generator technique in combination with subsequent density-gradient purification. This procedure leads to high yields of islets coated with a tailored, thin layer of cross-linked alginate which protects the islets against cytotoxic compounds present in human plasma. The recovery of encapsulated rat and porcine islets was about 70%. Empty capsules were nearly completely removed. Using this technique, the total volume of the resulting microcapsules increased only by a factor of about 1.5 compared to the volume of free islets. The technique can be used for large-scale production of coated islets.

Alginates↗
PubMed1987

Differential immunocytological expression of a paraprotein-associated idiotype is possibly related to variant immunoglobulin molecules in plasmacytoma cells.

An anti-idiotype antibody (anti-Id Ab) was made by immunization of a rabbit with the IgG-2/lambda paraprotein from a plasmacytoma patient (Sa). The antibody was directed against determinants of heavy (H) and light (L) chains on the F(ab)2 piece of the paraprotein. Using this antibody an unusual pattern of cytoplasmic fluorescence was seen with bone marrow cells of the patient. One population (type I) showed reactivity in association with gamma and lambda chains, the other (type II) with the anti-Id Ab only. So, by immunological methods, biclonality could be demonstrated using the anti-Id Ab but not with anti-isotype antibodies. L chains of mol. wt 23.5 and 17.0 kd were observed. The H and L chains of small molecular weight were not detected in the patient's serum nor in the culture supernatant. Thus, deleted and intracellularly degraded H and L chains may cause the unusual staining pattern of the type II cells.

Antibodies, Anti-Idiotypic↗
PubMed1984

Ultrastructural analysis of human plasmacytoma cells prepared on affinity beads after exposure to anti-idiotype antibodies.

Mononuclear cells from a bone marrow infiltrated by plasmacytoma cells were examined by electron microscopy. An analysis was performed according to different cytoarchitectural forms of the endoplasmic reticulum (ER). Six types of plasma cells could be distinguished. The bone marrow cells were treated with an anti-idiotype antiserum from a guinea pig prepared against the patient's monoclonal serum protein and with a FITC conjugated anti-guinea pig antiserum from the rabbit as second layer. Then the cells were passed through an affinity gel column with anti-FITC antibodies. The original preparation and the cells separated on the affinity gel were analysed by electron microscopy. It was found that an ultrastructurally distinct type of plasma cell was enriched 3.5-fold over the original sample by the separation procedure.

Antibodies, Anti-Idiotypic↗
PubMed1983

Results with a modified human myeloma stem cell assay.

The human tumor stem cell assay (HTSCA) introduced by Hamburger and Salmon [2] was modified in several details. It was found that a short period of treatment with deoxyribonuclease (DNase) of the material aspirated from the patients bone marrow greatly enhances the production of single cell suspensions and thereby may improve the assay. Instead of the dextran sedimentation method, we used the density gradient centrifugation method according to Bøyum [1] for the isolation of mononuclear cells from the bone marrow. Another methodical modification introduced by us is the use of the same medium for culturing the cells before plating them and in the agar after plating. Under the conditions reported here the formation of colonies was observed in 8 of 11 samples from individual myeloma patients. The average plating efficiency was 0.024% with a range of 0.009% to 0.039% showing that possibly an improvement was achieved when compared to the results obtained with the original method showing an average plating efficiency of 0.014% [2].

Aged↗
PubMed1983

Properties of an anti-idiotype antiserum: demonstration of cross-reacting mitogenic determinants on bone marrow plasmacytoma cells.

An antiserum against a monoclonal protein of IgG/kappa type from a patient S. was produced by immunization of guinea pigs. Idiospecificity of the antiserum (anti-Id AS) was tested by immunoprecipitation and hemagglutination inhibition. About 70% mononuclear cells prepared from the bone marrow (BM) aspirate of this patient stained positive when the antiserum was used in an indirect immunofluorescence (IF) procedure detecting surface membrane structures. Commercial antisera specific for gamma, kappa and lambda immunoglobulin (Ig) chains stained only 5-17% of the cells. With mu chain and delta chain specific antisera no reactivity could be observed. The presence of idiotype cross-reacting determinants (Id-CR-D), that is idiotypes not associated with Ig isotypes could be also demonstrated by a significant increase of 3H-thymidine incorporation of the BM cells in the presence of the anti-Id AS. Phytohemagglutinin (PHA), pokeweed mitogen (PWM) and concanavalin A had no effect. In a cell sorting experiment using affinity gel chromatography it could be shown that the anti-Id AS preferentially binds to proplasmacytes. Cells of this type were enriched two-fold over plasma cells in the eluate. The analysis of peripheral blood lymphocytes (PBL) from the patient revealed about 40% positive cells without correlation to a certain subpopulation. Administration of prednisolone to the patient resulted in a significant reduction of the Id positive cells within two days. In conclusion it appears that our antiserum detects cells of an individual tumour clone within PBL and BM-cells. By the stimulating effect of the anti-Id AS a proliferative potential of plasmacytoma cells could be defined which may work also 'in vivo'. Thus, Id-CR-D may operate as a tumour growth receptor.

Antigens, Surface↗
PubMed1982

Extramedullary multiple myeloma. A qualitative and quantitative electron microscopic study.

A case of multiple myeloma with a mediastinal tumor and other unusual findings is described. The findings included the presence of extramedullary tumor masses at multiple sites in addition to the medullary tumor and, more interestingly, the occurrence of pleural and peritoneal effusions. The plasma cells from these effusions were analyzed using stereological morphometric methods. The plasma cells were also cultured and established as a continuous cell line and were studied using the same methods. Our results indicate that there are qualitative and quantitative morphologic differences between the pleural and peritoneal plasma cells. Comparison between plasma cells and cultured cells from the intraperitoneal exudate showed marked morphologic differences. The analysis of these differences indicated that mature plasma cells, when subjected to culture, were transformed into immature lymphoid cells.

Aged↗
PubMed1981

Terminal deoxynucleotidyl transferase (TdT) and membrane receptors in human leukemia and lymphoma -- first experience with lyophilized cells.

Surface marker analyses and TdT assays were performed on cells from 31 patients. A variety of diagnoses were made and categorized as follows: acute leukemia (group I), non-Hodgkin lymphoma (group II) and diverse diagnoses (group III). Levels of TdT in the range from 0 to 7.9 U/mg lyophilized blasts from the peripheral blood were found in AL. This corresponds to 0-95 U/10(8) cells. Preparations of mononuclear cells from the peripheral blood of healthy donors showed TdT values up to 0.88 U/mg or 10.6 U/10(8) cells. High TdT activity was observed in a patient with AML, type M1 according to the FAB classification. In a patient with ALL (L1) cytostatic treatment effected the clearance of TdT activity from the peripheral blood cells and at the same time induced a significant increase of E rosette forming cells. Combined studies of the TdT activity and cell surface markers may enable us to define remissions and relapses of AL more precisely than it is possible by conventional cytological methods. Within the group II two patients with moderate TdT activities of 1.2 and 1.28 U/mg, respectively, were observed whose cells were of prolymphocytic or unclassifiable appearance, respectively. The TdT assay may be helpful to identify such cells of unknown origin and in addition may provide the means of discrimination between such cases and ALL patients who mostly show high TdT activities. Another result of our studies was the finding of moderate TdT activity of 1.2 U/mg with cells from the pleural effusion of a patient with Hodgkin's disease. Cells from malignant effusions from a patient with melanoma and a patient with teratoid carcinoma showed no TdT activity. Cells form the peripheral blood and from the bone marrow of a patient with blast crisis of CML showed TdT activity of 1.52 and 2.72 U/mg, respectively. Two other patients with blast crisis were negative. Not TdT activity was found in leukemic plasma cells. Our results show that lyophilized cells can be used for determinations of TdT activity. This greatly facilitates multi-parameter studies including cytological, cell surface marker and biochemical analyses.

Adolescent↗
PubMed1980

Study of uroproteins in myeloma patients by sodium dodecyl sulfate-polyacrylamide gel electrohporesis (SDS-PAGE).

Samples of the urine of 10 myeloma patients with proteinuria were examined by SDS-PAGE. Light chain proteins of Bence Jones (B.J.) type were excreted by 7 patients as monomer (m.w. 20--26.5 x 10(3) Dalton, by 2 patients as a mixture of monomer and dimer and by one patient as dimer. By two-dimensional electrophoresis in SDS-PAG and subsequent electrophoresis in agarose containing kappa and lambda chain specific antibodies the immunological identity of monomeric and dimeric B.J. protein of one patient has been shown. The two-dimensional analysis has been proven a valuable procedure in cases with the excretion of complete monoclonal protein and B.J. protein at the same time.

Bence Jones Protein↗