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Biomedical subjects

E Fischer

Publications and source records attributed to E Fischer.

At least 145 records · Page 8Linked to original sources
PubMed1988

[Status and frequency of local juxta-articular demineralization and erosion in the wrist area in the early phase of chronic polyarthritis. Results based on 3-dimensional soft x-ray pictures].

In early rheumatoid arthritis the location and incidence of localized juxta-articular demineralizations and erosions were investigated at 53 points of the wrist. On the level of the metacarpal bases, the distal and proximal row of the carpal bones more changes are seen in the oblique vd. and the lateral view than in the dv. view. At the distal bones of the forearm more changes are seen at the radius than at the ulnar styloid. The most often changes at all occur at the volar middle third of the triquetrum in the oblique view and at the distal volar articular facet of the scaphoid in the lateral view. Close relations between localized juxta-articular demineralizations and erosions do not exist. If the early bone changes at the wrist in rheumatoid arthritis are to be detected additional oblique and lateral view are prerequisite.

Adult↗
PubMed1988

[Quantitative computerized tomographic determination of bone mineral content].

Quantitative computed tomography (QCT) for measuring bone mineral content of lumbar vertebrae is increasingly used internationally. The effect of using conventional CT (single energy CT, SE-CT) and dual energy CT (DE-CT) on reproducibility has been examined. We defined a standard measurement protocol, which automatically evaluates a calibration phantom. This should ensure an in vivo reproducibility of 1 to 2%. Reference data, which has been obtained with this protocol from 113 normal subjects, using SE-CT and DE-CT, are presented.

Adult↗
PubMed1988

Characterization of a monoclonal antibody MoAb bH6 reacting with a neoepitope of human C3 expressed on C3b, iC3b, and C3c.

Activation products of the complement cascade contain neoepitopes that are not present in the individual native components. Monoclonal antibodies detecting neoepitopes have been used for direct quantification of activation at different steps in the cascade. These methods are suggested to be more sensitive and reliable than conventional complement activation tests, which are hampered by precipitation or fractionation procedures. The present study describes production screening and characterization of a monoclonal antibody (MoAb) bH6. MoAb bH6 exhibited a significantly higher binding capacity to ELISA plates coated with zymosan-activated human serum than to plates coated with EDTA plasma. When fixed to the enzyme-linked immunosorbent assay (ELISA) plates, MoAb bH6 retained material from zymosan-activated serum that only reacted with anti-C3 antibodies. Crossed immunoelectrophoresis performed on zymosan-activated serum demonstrated that MoAb bH6 co-precipitated with anti-C3c antibodies. In experiments using highly purified cell-bound fragments MoAb bH6 showed reactivity with C3b and iC3b, but not with C3d. MoAb bH6 reacted in ELISA with purified C3c, but not with C3dg, both as capture antibody and in tests with the fragments absorbed to the solid phase. Thus, MoAb bH6 is highly specific for a neoepitope of human C3 expressed on the cleavage fragments of C3b, iC3b, and C3c.

Antibodies, Monoclonal↗
PubMed1988

gp 58/68, a parasite component that contributes to the escape of the trypomastigote form of T. cruzi from damage by the human alternative complement pathway.

A glycoprotein of apparent molecular weight 58,000 (unreduced)/68,000 (in its reduced form) (gp 58/68), which is one of the fibronectin/collagen receptors of Trypanosoma cruzi, was purified to homogeneity from the trypomastigote forms of the Tehuantepec and Y strains of the parasite. Purified gp 58/68 inhibited formation of cell-bound and fluid-phase alternative pathway C3 convertase in a dose-dependent fashion, as assessed using purified human complement components. Gp 58/68 differed from the human regulatory proteins H, DAF, MCP and CR1 and from previously reported regulatory proteins on the parasite membrane in that it was unable to enhance decay-dissociation of preformed alternative pathway C3 convertase sites, did not serve as a co-factor for I-mediated cleavage of C3b and had no inhibitory activity on the classical pathway convertases. The inhibitory effect of gp 58/68 was most likely dependent on an interaction of the protein with factor B rather than with C3b. Gp 58/68 provides trypomastigotes with an additional potential mechanism for escaping complement lysis by the human alternative pathway.

Animals↗
PubMed1988

[Piso-triquetral arthrosis and the so-called pisiform secundarium].

After scapho-trapezial osteoarthritis, piso-triquetral is the next most common. Some of the various changes of the piso-triquetral osteoarthritis are also to be seen in the dorso-volar view. The so-called secondary pisiform is not a congenital variant but develops with increasing frequency in older age as one of the features of the osteoarthritic reactions.

Adult↗
PubMed1987

Functional role of the alpha-chain of complement receptor type 3 in human eosinophil-dependent antibody-mediated cytotoxicity against schistosomes.

The participation of complement receptor type 3 (CR3) in antibody-dependent effector function of human eosinophils against parasites was studied by using monoclonal antibodies directed against various surface molecules. Both adherence and cytotoxicity of hypodense eosinophils to IgE-coated schistosomula of Schistosoma mansoni were strongly inhibited by anti-CR3 antibodies (OKM1 or Mo1). The specificity of the inhibitory effect for the alpha-chain of CR3 was shown by the lack of inhibition of anti-beta-chain or anti-LFA1 alpha-chain monoclonal antibodies, although these antigens were expressed on human eosinophils. These results associated to previous works on IgE receptors demonstrate that both receptor for Fc fragments of IgE and CR3 are essential in IgE-dependent cytotoxicity of human eosinophils. Flow microfluorometry analysis revealed that hypodense eosinophils were more intensively stained by OKM1 antibodies than the normodense populations. In the case of IgG-mediated cytotoxicity by normodense eosinophils, only the enhancement of cytotoxicity due to monokine activation was inhibited by anti-CR3 alpha-chain antibodies. These findings suggest an increased expression of CR3 on eosinophils after activation either in vivo or in vitro. The participation of CR3 in IgE-mediated cytotoxicity against schistosomes was also required in the case of blood monocytes but not for platelet-mediated killing, which does not require prior adherence. The biologic role of CR3 is therefore extended to effector mechanisms involving eosinophils and two different isotypes of antibodies and possibly implied in immunity against schistosomes.

Antibodies, Monoclonal↗
PubMed1987

Human diseases associated with C3 receptor deficiencies.

Genetic deficiencies of complement receptors have recently been described. CR1 expression is reduced on erythrocytes, leucocytes and podocytes of many patients with systemic lupus erythematosus because of both genetic and acquired mechanisms. CR1 deficiency is also found in AIDS and AIDS-related syndromes and correlates with clinical subpopulations of HIV-infected patients. The pathogenic significance of CR1 deficiency relates to the functions of CR1 in clearance of immune complexes, phagocytosis and immune regulation. CR3 deficiency occurs as an autosomal recessive inherited disease characterized by the lack of or severe reduction in expression of the leucocyte antigens CR3, LFA1, p150,95 and their common chain. The disease is associated with severe defects in neutrophil and lymphocyte functions and recurrent bacterial infections. The in vivo effects of C3 receptor deficiencies emphasize the critical role of these membrane molecules in immunity.

Acquired Immunodeficiency Syndrome↗
PubMed1987

[Soft tissue changes in the hands in progressive scleroderma (excluding calcifications)].

The systemic progressive sclerosis causes numerous soft tissue changes at the hand, most often a thickening of the skin and an augmentation of the fibrous structures in the subcutis, which occur before the atrophy of the finger tip. Other soft tissue changes are the synovitic enlargement of the joint capsules and the tendon sheaths and the tendinitic enlargement of the tendons. This complex of soft tissue changes is seen in the three view low kV radiography.

Finger Joint↗
PubMed1987

[Manifestations of diffuse idiopathic skeletal hyperostosis on the forefoot].

Diffuse idiopathic skeletal hyperostosis (DISH) also becomes noticeable at the numerous entheses of the forefoot mainly with exomarginal formation of spongious bone. The separate entheses react differently to enthesiopathic stimuli. In DISH the tuberosities of the distal phalanges react most frequently and most severely. Between the toes and the digits there are differences in DISH not only of a quantitative but also of a qualitative nature. At the toes the increased subchondral sclerosis does not occur as it does at the digits.

Adult↗
PubMed1987

Expression of CR1 and CR2 complement receptors following Epstein-Barr virus infection of Burkitt's lymphoma cell lines.

Epstein-Barr virus (EBV) infection of human B lymphocytes involves a specific receptor closely associated with, or identical to, the C3d complement receptor, CR2. Thus, 25 out of 29 EBV-positive Burkitt's lymphoma (BL) cell lines but none of 15 EBV-negative BL lines were found to express C3 receptors. Furthermore, in vitro infection with EBV of six EBV-negative cell lines resulted in the expression of C3 receptors in association with that of EBV-determined nuclear antigen (EBNA). Rosette assays using erythrocytes coated with human C3b, C3bi, and C3d, inhibition of rosette formation with anti-receptor antibodies, and flow cytometry analysis of stained cells demonstrated that EBV-converted lines expressed C3b and C3d receptors, CR1 and CR2. Anti-receptor antibodies recognized an average of 40,700 anti-CR1 and 140,000 anti-CR2 binding sites on an EBV-converted line (BL41/B95), whereas no specific binding occurred on the corresponding EBV-negative (BL41) cells. Because CR1 and CR2 are involved in B-cell proliferation and/or differentiation, enhanced expression of C3 receptors following the interaction between EBV and B cells and/or subsequent infection of the cells by EBV may provide a basis for positive control of B lymphocyte proliferation by EBV.

B-Lymphocytes↗
PubMed1987

[Etiology of bony bridges on the sides of the terminal phalanx of the great toe].

Bony bridges along the sides of the terminal phalanx of the great toe occur not only in acromegaly but also in one third of cases with peripheral signs of diffuse idiopathic skeletal hyperostosis. Systemic diseases, such as rheumatoid arthritis or psoriatic arthritis with chronic inflammation of the interphalangeal joint of the great toe or extraarticular osseous changes in the terminal phalanx of the great toe do not influence the development of such bridges.

Arthritis↗
PubMed1987

[Arterial calcifications of the hand: normal aging and the course in chronic dialysis patients].

Normally, arterial calcifications in the hand progress from proximal to distal and do not reach the fingers by the 8th decade. In patients on maintenance dialysis arterial calcifications begin earlier and do not progress with age. The most severe arterial calcifications occur in patients with renal failure caused by diabetic nephropathy. Prognostically arterial calcifications in the finger-metacarpal region are an unfavourable sign.

Adult↗
PubMed1987

Scintigraphic evaluation of brain death: significance of sagittal sinus visualization.

Radiotracer scintigraphy has been commonly used in this country to confirm and document the clinical diagnosis of brain death. Whether the presence of radiotracer activity in the region of sagittal venous sinus (SVS) represents actual blood flow to the brain in the absence of demonstrable cerebral arterial flow remains a controversial issue. Our retrospective study was performed to review the significance of such sagittal tracer activity. Of the 53 patients showing no cerebral arterial flow, 26 showed tracer activity in the region of SVS. The clinical status, EEG findings, and outcome of all 53 patients were the same irrespective of the presence or absence of SVS tracer activity. We conclude that the mere presence of SVS in the absence of demonstrable cerebral arterial flow activity is not clinically significant and does not contradict the diagnosis of brain death.

Brain Death↗
PubMed1986

Characterization of the human glomerular C3 receptor as the C3b/C4b complement type one (CR1) receptor.

The functional and immunochemical characteristics of the human glomerular C3 receptor were investigated by adherence of sheep erythrocytes (Es) coated with defined C3 fragments and by using polyclonal and/or monoclonal antibodies directed against epitopes expressed on complement receptors CR1, CR2, and CR3. C3b-bearing Es (EsC3b) strongly adhered to glomeruli in frozen kidney sections in a reaction that was selectively inhibited by F(ab')2 anti-CR1 antibodies. There was no adherence of EsC3dg, EsC3d, and EsC3bi in the presence or absence of Ca++ and Mg++ under physiologic buffer conditions. The weak glomerular binding of EsC3bi, which was observed in half-isotonic buffer was selectively suppressed by anti-CR1 antibodies. By indirect immunofluorescence, anti-CR1 antibodies stained all podocytes in glomeruli, whereas no staining of kidney sections was seen with OKM1 and anti-Mol antibodies directed against the alpha-chain of CR3 and with anti-CR2 antibodies anti-B2 and BL13. Solubilization of membrane glycoproteins from freshly isolated glomeruli from three human kidneys, in the presence of 0.1% Nonidet P-40, yielded a material that bound to lentil lectin Sepharose and could accelerate the decay of preformed cell-bound amplification C3 convertase sites in a reaction that was inhibited by anti-CR1 antibodies. The material containing CR1 activity was labeled with 125I, immunoprecipitated with anti-CR1, and analyzed by SDS-PAGE and autoradiography. Anti-CR1 immunoprecipitated a form of CR1 of Mr 205,000 in solubilized glomeruli from three donors, and an additional form of Mr 160,000 in glomeruli from two of the donors. Immunoprecipitation of CR1 from surface-labeled erythrocytes from these individuals demonstrated them to be homozygous for the 205,000 Mr form of the receptor. Whether the 160,000 band represents in vitro or in vivo proteolytic cleavage of CR1, or cell specific-modulation of gene expression of glomerular CR1, remains unclear. Thus, CR1 is the only type of C3 receptor expressed in the human kidney. Glomerular CR1 shares the functional antigenic and biochemical properties of the C3b/C4b CR1 receptor of peripheral blood cells.

Animals↗