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Biomedical subjects

J Duheille

Publications and source records attributed to J Duheille.

At least 19 recordsLinked to original sources
PubMed1992

Synthesis of new hydrophilic microspheres: optimized carriers for microparticle-enhanced nephelometric immunoassays.

To optimize antigen-antibody reactions, we have synthesized chemically well-defined hydrophilic microspheres. Proteins or haptens were covalently linked to these carriers. When the microsphere conjugates were agglutinated by the corresponding antiserum, the size of the complex artificially increased during the immunological reaction. After optimizing various parameters such as the hydrophilic character, repulsion charges, and amount of antigen coupled to the microspheres, we developed a rapid and sensitive immunoassay based on laser light scattering by the complexes.

Animals↗
PubMed1992

Microparticle-enhanced nephelometric immunoassay for human C-reactive protein.

Polyfunctional hydrophilic microspheres of 125-nm diameter can be produced by copolymerization of acrylic monomers. Purified c-reactive protein (CRP) was covalently bound to these new micropheres, and the conjugate obtained was used as reagent in a microparticle-enhanced nephelometric immunoassay for human CRP. This assay was based on the measure, with a specially designed nephelometer, of the light scattered by aggregates formed during the immunoagglutination of the conjugate with anti-CRP antiserum. Sensitive inhibition of this agglutination by free CRP (6 ng/ml) allowed CRP quantitation in highly diluted serum samples (1/500-1/2,000), excluding any interference or sample pretreatment. The CRP assay was easy to perform (no washing or phase separation), reliable (coefficients of variation ranged from 1.3% to 9.3% for within-run and between-run determinations), and accurate (mean percentage of recovery: 104%; correlation coefficients with accepted analytical methods greater than or equal to 0.97) over a large range of concentrations. The inhibition mode excluded errors in the antigen excess zone and provided total security at high concentrations.

C-Reactive Protein↗
PubMed1992

Development of a rapid microparticle-enhanced nephelometric immunoassay for serum myoglobin in acute myocardial infarction.

A microparticle-enhanced nephelometric immunoassay was developed for myoglobin quantitation in human serum. It uses rabbit antimyoglobin serum and hydrophilic polyacrylic microparticles covalently coated with baboon myoglobin in a competitive immunoagglutination system. The level of microparticle agglutination is assessed with a specially designed nephelometer. This sensitive (45 ng/ml of myoglobin detected in serum) and accurate (coefficients of variation from 3.0% to 8.2% in precision study and linear recovery of myoglobin in overloaded sera) immunoassay was evaluated with human sera from patients suffering from acute myocardial infarction. Myoglobin levels in patient's serum on admission appeared to be correlated with clinical and biological parameters assessed in emergency wards and later. This new, rapid, and easy microparticle-enhanced nephelometric immunoassay could thus be useful in emergency conditions for the early quantitation of serum myoglobin.

Adult↗
PubMed1992

Measurement of eleven serum proteins by microparticle-enhanced nephelometric immunoassay.

Eleven proteins (immunoglobulins IgG, IgA, IgM, orosomucoid, alpha 1-antiproteinase, haptoglobin, ceruloplasmin, C-reactive protein, transferrin, prealbumin and alpha 2-macroglobulin) in human serum were quantitated by a new microparticle-enhanced nephelometric immunoassay. This is a one step competitive assay, based on the nephelometric measurement of light scattered by clusters of protein-coated microparticles specially synthesized for that use. Statistical evaluation (precision, recovery and method comparison) shows that the determination of serum proteins is reliable and accurate for wide ranges of concentration and that the method is quite adequate for strongly increased concentrations. This microparticle-enhanced nephelometric immunoassay appears to offer an alternative method for routine measurement of a great variety of serum proteins at high and intermediate concentrations, which are usually quantified by radial immunodiffusion or conventional immunonephelometry. On account of its sensitivity, it can also be used for the determination of relatively low concentrations of analytes.

Blood Proteins↗
PubMed1992

Detection of antithyroglobulin autoantibodies with defined epitopic specificity by a microparticle-enhanced nephelometric immunoassay.

To hydrophilic, polyfunctional spherical microparticles of predetermined diameter, produced by copolymerization of acrylic monomers, we covalently bound human thyroglobulin. The thyroglobulin-microsphere conjugate was agglutinated, in the presence of antimouse immunoglobulins antiserum, by four monoclonal antibodies, each recognizing a different antigenic domain on the thyroglobulin molecule. These agglutinations were quantified by measuring with a specially designed nephelometer the light scattered by clusters of the conjugates. Agglutination with the monoclonal antibody recognizing antigenic domain II of the thyroglobulin molecule was specifically inhibited by some human sera that contained antithyroglobulin autoantibodies. This allowed us to develop a microparticle-enhanced nephelometric immunoassay for these autoantibodies with defined epitopic specificity. Using this assay, we detected and quantified antithyroglobulin autoantibodies in serum samples from all eight patients examined with Hashimoto disease and from most (75%) patients with untreated Graves disease.

Adult↗
PubMed1991

A microparticle enhanced nephelometric immunoassay (Nephelia) applied to thymulin measurement.

This article describes a microparticle enhanced nephelometric immunoassay (Nephelia) applied to the quantification of the thymic peptide hormone thymulin. Nephelia uses antibody recognition by the antithymulin antiserum in a competitive reaction between free thymulin and thymulin bound to the microspheres. The binding between microsphere and thymulin is achieved with the aid of a protein carrier. The sensitivity of the competitive reaction varied with the protein carrier and the antiserum sample. The most efficient reaction was obtained with the thymulin-metallothionein-microsphere conjugates; as little as 5 pg/ml of thymulin could be detected. In adult human serum or in its ultra-filtrate, spiked synthetic thymulin was totally recovered. Measurement of thymulin in serum or ultra-filtrate samples demonstrated the presence of interference from molecules in the serum. Nephelia led to the same conclusions as those reported with other methods and performs as well, and is more simple to use than radio- or enzymo-immunoassays for thymulin measurement.

Adult↗
PubMed1991

Polyacrylic microspheres as a solid phase for microparticle enhanced nephelometric immunoassay (NEPHELIA (R)) of transferrin.

Polyfunctional hydrophilic microspheres (MS) can be produced by copolymerisation with gamma-irradiation of acrylic monomers. Transferrin (TRF) can be covalently bound to these MS by reaction between aldehyde groups of the MS and primary amino groups of the protein. MS-TRF conjugates thus obtained are agglutinated by specific antiserum and this agglutination is inhibited by free TRF. Agglutination and inhibition are quantified by measurement of the light scattered by MS-TRF conjugate clusters with a specially designed nephelometer, a process designated as microparticle enhanced nephelometric immunoassay (NEPHELIA (R)) for TRF. Recovery, correlation and reproducibility studies, simultaneously performed in three different laboratories, show that this TRF immunoassay is accurate for a large concentration range. NEPHELIA (R) may appear as an alternative method for a large variety of molecules.

Humans↗
PubMed1990

[In vitro study of the cytocompatibility of 3 biological glues].

Human derived fibrin glues are being used with increasing frequency in periodontal surgery. Three different fibrin glues were tested in an in vitro system for gingival fibroblast proliferation. The results show a cytocompatibility of these products which justifies their employment in periodontal therapy.

Biocompatible Materials↗
PubMed1979

[Study of cellular elements in synovial fluid in scanning electron microscopy].

Scanning electron microscopy allows a tridimensional morphological study of the cellular elements of the pathological human synovial fluid. The cells are grouped into two populations: macrophage cells and round cells, whose differentiation is more difficult: polynuclears, lymphocytes and synovial cells. The combination of scanning electron microscopy and X-ray diffraction makes it possible to describe and indentify crystals of sodium urate and of triclinical, dehydrated calcium pyrophosphate.

Arthritis, Rheumatoid↗
PubMed1977

[Scanning electron microscopy study of the synovial membrane in rheumatoid arthritis].

A comparative study under the scanning electron microscope of rheumatoid synovial membranes, 5 arthrosic synovial membranes, one tuberculous membrane, and 3 normal synovial membranes showed the pathological changes in the synovial membrane due to rheumatoid arthritis: Inflammatory aspect of the synovial fringes, surrounded by turgid and proliferative villous processes. Granular appearance of the endo-articular surface like a "pebble beach". Dome-shaped synoviocyte layer, standing out well above the subjacent intimal layer, associated with small round cells, also with a raised margin, covering most of the endo-articular surface. Plasma membrane of the superficial synovial cells, covered with numerous and various differentiations and abundant microvillous processes. Reticular deposits or layers, covering the apical poles of the synoviocytes.

Arthritis, Rheumatoid↗
PubMed1977

[Identification of the crystals observed in the destructive arthropathies of chondrocalcinosis].

Study of the synovial membrane and cartilage demonstrating two destructive arthropathies of the knee diagnosed in subjects with articular pseudogout. Scanning electron microscopy reveals the presence of many crystals on the surface of the cartilage and the synovium and in the depth of the cartilage. These can be grouped into two families on the basis of dimensions and morphology. The first consists of those shaped like arrowheads and are large (80-100 microns long.) They were formally identified using Weissenberg's technique; dihydrated calcium hydrogenophosphate (CaHPO4.2H2O) is involved here. In the second family the crystallogenesis is different (prism or lozange-shaped) and the crystals themselves have not been identified with certainty because of their tiny size (20 microns). The hypothesis is proposed that the crystals of dihydrated calcium hydrogenophosphate properly belong to the destructive arthropathies of pseudogout; while not necessarily its cause, they may help explain its development.

Aged↗
PubMed1976

[Autoimmune mechanisms and post-anesthetic hepatitis].

After a brief review of clinical, biological and immunological features of post anesthesia hepatitis and hepatic auto-immunity, the authors attempt to determine whether certain forms of post-anesthesia hepatitis can be placed under the heading of autoimmune liver disorders, the mechanisms by which auto-immunity can be induced and modulated and the practical implications of these concepts, namely with regard to detection of subjects at risk.

Anesthetics↗
PubMed1976

[Pigmented villonodular synovitits of the hip: ultrastructure and aspects on scanning electron microscopy].

The authors studied one case of pigmented, villonodular synovitis (PVNS) of the hip by means of optical microscopy and by transmission and scanning electron microscopy. Scanning electron microscopy showed that the surface of the PVNS is completely different from that of rheumatic synovitis, in particular that of rheumatoid synovitis. The composition and the cellular morphology of the outer layer of the PVNS appear, however, to be similar to those of normal synovial membrane of arthrosic synovial membrane. Clumps of red corpuscles, enclosed in a fibrin network, were visible on the surface of the PVNS in a way that the authors has never seen previously in the 19 other human synovial membranes, normal and pathological, they had studied in this way. The totality of the microscopic findings confirms the importance of the role played by the intra-articular and intra-synovial haemorrhages, and by the macrophage reactions that follow, in the development of the lesions that characterize PVNS.

Adult↗
PubMed1976

[Contribution of scanning electron microscopy to the study of normal and pathological human synovial membrane].

Scanning electron microscopy permits three-dimensional morphological study of the outer layer of the synovial membrane. This article concerns the study of 15 surgical samples of normal and pathological human synovial membranes: 3 normal synovial membranes, 6 inflammatory synovial membranes, 5 arthrosic synovial membranes, 1 tuberculous tenosynovitis. The samples were washed, fixed in a mixture of glutaraldehyde and iso-osmotic paraformaldehyde, dehydrated in increasing concentrations of alcohol and at the critical point, and then subjected to double metallization (aluminium and gold). Certain portions were treated with hyaluronidase. Hypertrophy of the villi, considerable in inflammatory synovial membranes, minimal in arthrosic synovial membranes, and absent in the normal synovial membrane, was confirmed. The outer layer is composed of cells of different sizes with spaces betwen, in which images indicating intercellular bridges can just be seen. The surface of the cells is irregular and covered with numerous microvilli. The arthrosic synovial membrane is poorly with large cells; in contrast in an inflammatory synovial membrane they are numerous, globular, and project from the surface.

Arthritis, Rheumatoid↗