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Biomedical subjects

W Müller-Ruchholtz

Publications and source records attributed to W Müller-Ruchholtz.

At least 73 records · Page 4Linked to original sources
PubMed1989

[Exchange of the hematopoietic system changes chemosensory identity].

It has been shown that the scent of mice changes after a bone marrow transplantation. Previously obtained results were re-examined with a new design that rules out possible avoidance learning effects. Two BALB/c mice, deprived of water for 20 hours each day, were trained in a Y-maze to discriminate two fully allogeneic mice strains (C3H = S+ and C57 = S-) via their urine odor. Reinforcement for correct choice was provided by a drop of water. Urine samples of different fully allogeneic mice strains (C3H, C57 and A/J) and bone marrow transplanted chimeras (C57----C3H and C3H----C57) were submitted to different "transfer of training" -tests. In the conditioning paradigm used, the animals learn to identify S+ and also do not avoid S- after the training. The urine odor of the C57----C3H-chimeras was found to be different from the strain-specific urine odor of C3H animals. Since this change could not be found in syngeneic transplanted chimeras, it is concluded that it is caused by the graft. The experiments failed, however to demonstrate that the urine odor of allogeneic chimeras is constituted solely by donor- and recipient-specific components.

Animals↗
PubMed1988

Morphologic characteristics of developing osteoarthrotic lesions in the knee cartilage of STR/IN mice.

The development of osteoarthrotic cartilage lesions in the knee joints of male STR/IN mice was studied with respect to their histologic appearance and their various localizations in the joint. Spontaneous articular cartilage degeneration on the medial portion of the tibial plateau was considered to be the initial event. Continued loss of cartilage subsequently led to a pronounced instability of the knee joint, with a varus deformity. This was followed by medial patellar luxation with corresponding osteoarthrotic lesions at the facies patellaris femoris. The most marked osteoarthrotic cartilage degeneration developed on the medial tibial condyle and at the facies patellaris femoris of the femoropatellar joint. Histologic examination of the osteoarthrotic defects in these two regions revealed distinct morphologic differences with respect to formation of chondrocyte clusters, tendency to regeneration, and proliferation reactions. Lectin binding experiments in normal articular cartilage revealed regional differences regarding the presence or absence of keratan sulfate in the extracellular matrix. The lack of keratan sulfate in tibial cartilage might reflect its tendency to degenerate spontaneously. It is therefore suggested that male STR/IN mice are particularly useful for studying two different types of osteoarthrosis, one due to a biomechanically induced instability (patellar luxation) and one due to biochemical changes (absence of keratan sulfate) of still unknown pathogenesis.

Animals↗
PubMed1988

Lectin-binding in normal and osteoarthrotic articular cartilage from STR/1N-mouse knee joints.

Fluorescein-isothiocyanate (FITC) labeled lectins were used to study the distribution pattern of specific binding-sites in histological sections of normal and osteoarthrotic articular cartilage from the mouse knee joint. Male inbred mice of the STR/1N-strain develop spontaneous arthrotic articular cartilage lesions on the medial condyle of tibia and femur. The varus-deformity of the knee joint leads to a recurrent medial patellar luxation with osteoarthrotic defects on the medial part of the facies patellaris femoris. It was demonstrated that the lectin staining pattern of osteoarthrotic articular cartilage, especially on the facies patellaris femoris, was different from that of normal articular cartilage. The differences in lectin staining corresponded to those observed between normal and fibrillated articular cartilage from human patellae. The normal articular cartilage of the mouse knee joint possessed lectin binding-sites for Concanavalin A (ConA) and wheat germ agglutinin (WGA), but not for Ulex europaeus agglutinin (UEA), soy bean agglutinin (SBA) and peanut agglutinin (PNA). In addition to the completely changed distribution pattern of ConA and WGA in osteoarthrotic cartilage, SBA, PNA and UEA developed distinct staining patterns particular to the fibrillated areas of arthrotic cartilage. The increased lectin-binding to arthrotic articular cartilage may be due to unmasking of sugars in the course of bondage breakdown in fibrillated cartilage or the production of pathological glycoproteins. It is evident that lectins can demonstrate minute differences between normal and arthrotic cartilage and it is concluded, therefore, that lectins are sensitive and specific tools for the study of degenerative joint diseases.

Animals↗
PubMed1988

Carbohydrate-specific human heterophile antibodies in normal human sera that react with xenogeneic cells.

Human heterophile antibodies (HHA) that are present in normal human sera (NHS) play an important role in hyperacute xenograft rejection. The aim of this study was to analyze the occurrence, mode of action and molecular specificity of HHA in NHS that are directed against xenogeneic lymphocytes (isolated from mouse, rat, guinea pig, rabbit, cattle and pig) and isolated rat pancreatic islets. All sera contained variable amounts of HHA that killed the target cells via the classical complement pathway. The cytotoxic activity of these HHA was specifically inhibited by certain carbohydrates (alpha-D-melibiose, beta-lactose, beta-gentiobiose, beta-cellobiose, D-mannose, N-acetyl-beta-D-mannosamine and alpha-D-rhamnose) and by rat IgM. By means of affinity chromatography with immobilized inhibitors we obtained an antibody preparation of mainly IgG type from NHS (up to 3.5 mg/10 ml serum) that reacted strongly with rat lymphocytes and isolated rat pancreatic islets. Though thus far residual xenospecific antibody activity has remained in the sera even after multiple affinity chromatography, these data suggest that specific elimination of HHA is feasible and that it may be thus possible to overcome a major obstacle to xenotransplantation.

Antibodies, Heterophile↗
PubMed1988

Human monoclonal antibody against human lymphocytic cells. A human monoclonal antibody that reacts preferentially with human lymphocytic cells.

Human monoclonal antibodies may replace human or xenogeneic antisera and mouse monoclonal antibodies for therapeutic applications. The human IgM monoclonal antibody Ha6D3 was produced after in vitro immunization and fusion with a mouse myeloma. Its reactivity against human normal and leukemic cells was investigated in cytotoxicity assays, and the antigen distribution in normal tissues was investigated with biotinylated Ha6D3 and avidin-peroxidase complexes. It was shown that Ha6D3 reacts preferentially with human lymphocytic cells. Only moderate reactions with epithelial cells in some organs were observed in cryostat sections, but because of poor accessibility in vivo these reactions were considered to be negligible.

Antibodies, Monoclonal↗
PubMed1988

Measurement of rat insulin. Enzyme-linked immunosorbent assay with increased sensitivity, high accuracy, and greater practicability than established radioimmunoassay.

Total immunoreactive insulin (IRI) is conventionally determined by radioimmunoassays. IRI measurement in rats can be made more sensitive, accurate, and practical, as demonstrated by a new modified enzyme-linked immunosorbent assay (ELISA). It is characterized by indirect binding of an anti-insulin antibody by an antiglobulin antibody and uses the principle of competitive saturation. In this ELISA, IRI can be determined in a wide range of concentrations, corresponding to the standards. The standard curve ranges from 100 to 0.049 ng/ml IRI (1 ng/ml approximately 23.4 microU/ml approximately 172 pM rat insulin). The statistical analysis shows between- and within-assay coefficients of variation of less than or equal to 15%.

Animals↗
PubMed1988

Production and applications of new monoclonal antibodies against human lymphocyte antigen-A and -B antigens.

Monoclonal antibodies (MAbs) against HLA antigens can give better information about the serology and biochemistry of the human major histocompatibility complex (MHC) than HLA antisera obtained from pregnant women. To increase the very limited panel of MAbs against HLA we immunized mice with human cultured cell lines and fused their spleen cells with the Ag8-653 myeloma. We produced MAbs against HLA-A1, A2/w69, A2/28, A2/11/25/26/28/29/30/31/33/34, A25/32, B7/22, and B13. The best dilution medium to store the MAbs in Terasaki plates was RPMI 1640 supplemented with 7% bovine serum albumin. The MAbs are also excellent reagents to investigate public HLA antigens and to stain HLA antigens in cryosections of transplanted organs.

Animals↗
PubMed1987

Covalent conjugates of monoclonal antibody and cobra venom factor mediate specific cytotoxicity via alternative pathway of human complement activation.

Because of lack of unspecific toxicity autologous serum is the optimal source of complement for in vitro cell depletion in human bone marrow transplantation. Covalent binding of cobra venom factor to an antibody leads to a specific complement activating conjugate with cytolytic potential independent of the capacity of the antibody to fix complement itself. Therefore this conjugation allows the use of various sera, including human as the source of complement. The kinetics of cobra venom factor-initiated cytolysis is compatible with in vitro treatment of bone marrow prior to transplantation.

Antibodies, Monoclonal↗
PubMed1987

Comparison of gamma-interferon and alloantigen-induced T cell factors in the induction of MHC class II antigen expression and in the modulation of the immunogenicity of lymphocyte-free rat bone marrow.

In a rat model, we compared the effects of various soluble products released by T cells, such as the unspecifically acting gamma-interferon or the newly detected alloantigen-induced factors that specifically act on nonlymphoid, hemopoietic bone marrow cells. We found two types of reactivity patterns with regard to the induction of MHC class II antigen expression on these cells. The very same patterns could be demonstrated when we investigated the modulation of their stimulatory capacity, i.e., their immunogenicity in a T proliferation assay. These findings are discussed in relation to the increasing incidence of immunologically mediated graft rejections in clinical bone marrow transplantation following T cell purging.

Animals↗
PubMed1987

Transplantation of aortic and pulmonary allografts, enhanced viability of endothelial cells by cryopreservation, importance of histocompatibility.

Fresh heart valve allografts were preserved at 4 degrees C for 14 days, cryopreserved and stored for 63 days, and studied for endothelial viability and antigenicity, in order to obtain some information on the immunobiological status of allografts before transplantation. The surgical technique described by Ross for subcoronary position is preferred and briefly outlined. Four explanted incompatible allografts were studied by light and scanning electron microscopy and immunohistochemistry to assess the immunological reactions and tissue changes that occurred between 9 days and 16 weeks postoperatively. Valve leaflet motion and opening velocities were studied by echocardiography postoperatively to establish a baseline with which to distinguish early leaflet degeneration. Distensibility of the aortic annulus was studied postoperatively by supraaortic angiography to justify one of the goals of reconstruction of the aortic root with allografts. Antibiotic preserved allografts at 4 degrees C showed no viable endothelial cells after 8 days while the cryopreserved allografts demonstrated a high rate of viable endothelial cells capable of expressing surface antigens (HLA class I and II). Although the valve explants showed focal mononuclear cell infiltrations with T-lymphocytes, the allografts healed in place. The "classic" findings of rejection could not therefore be demonstrated. In summary, cryopreserved valve allografts, like the fresh, are antigenic. It is therefore recommended to use compatible valve grafts, when possible, which might be a positive step to improve the functional longevity of valve allografts. Immune response after valve allograft transplantation does not cause acute valvular dysfunction but rather chronic tissue changes which might lead to early degeneration of the allograft. The opening velocities of preserved aortic and pulmonary allografts were normal at 3-4 years postoperatively irrespective of histocompatibility. Echocardiography might be a useful tool to detect early degenerative changes of incompatible valve leaflets. The aortic root is distensible after allograft transplantation.

Adolescent↗
PubMed1987

Role of lymphocytes in the modulation of the immunogenicity of bone marrow: a rat model.

In a rat model we describe the role T lymphocytes play in the immunogenicity of bone marrow. Mainly they modulate the MLC-like stimulatory cell potential and the MHC class II antigen expression of nonlymphoid bone marrow cells via the release of newly detected specific soluble factors and immunologically unspecific ones. These findings are discussed in relation to the graft rejection encountered in clinical bone marrow transplantation following certain T depletion protocols.

Animals↗