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Biomedical subjects

J F Stoltz

Publications and source records attributed to J F Stoltz.

At least 325 records · Page 18Linked to original sources
PubMedDate not supplied

Preparation of varicella-herpes zoster immunoglobulin.

The efficacy of zoster immunoglobulin in prophylaxis of varicella and herpes zoster is reported by many authors. The screening for zoster's antibodies is performed in the blood donor population and in persons convalescing from herpes zoster. The results show that 25 per cent of blood donors and 83.5 per cent of convalescents, respectively, have CF antibody titer of l6. Varicella zoster immunoglobulin prepared by alcohol fractionation has a fluorescent antibody titer of 1,024 and a CF antibody titer of 512. These results are discussed and compared with those of the literature.

Adult↗
PubMedDate not supplied

[Use of standard for quantitation of adhesion of polynuclear neutrophils by flow cytometry].

Adherence receptors are essential for heterotypic (endothelial cell, platelet) polymorphonuclear neutrophil (PMN) interaction. Determination of their expression level give information about activation state and functionality of PMN. Use of flow cytometry associated with an immunolabeling standard, represented by beads coated by a determined amount of immunoglobulins (Qifikit, Dako), allows analysis of specific antibody binding capacity and gives information about antigen density. Using this methodology, the exploration of surface adherence receptors, L-selectin (CD62L) and b2-integrins (CD11a-c/CD18) from PMN unstimulated and incubated with pro-inflammatory stimuli, formyl-methionyl-leucyl-phenylalanine (fMLP) and tumor necrosis factor a (TNFa), allows, on the one hand, the establishment of basal expression values on resting PNN and on the other hand, the study of PNN reactivity. This method of quantification can be applied to clinical studies as adherence receptor deficiency syndromes or inflammatory, infectious and vascular diseases.

Adult↗
PubMedDate not supplied

Influence of mechanical stress on cell viability.

The cartilage is a hydrated connective tissue in joints that withstands and distributes mechanical forces. The chondrocytes utilize mechanical signals to regulate their metabolic activity through complex biological and biophysical interactions with the extracellular matrix (ECM). The aim of this work was to study the influence of mechanical stress on cells behavior cultured in 3D biosystems (alginate and alginate supplemented with hyaluronate). After mechanical stimulation, cell viability and cell death process were the main studied parameters. Our results indicated that viability and cell cycle progression were inhibited under mechanical stimulation, as far as the extracellular matrix was not yet synthesized. In contrast, on day 21, the mechanical stimulation had positive effect on these parameters.

Alginates↗
PubMedDate not supplied

IL-1beta synthesis by chondrocyte analyzed by 3D microscopy and flow cytometry: effect of Rhein.

Several factors are known to be involved in the destruction of the articular cartilage. Interleukin-1 (IL-1) plays an important role in the pathogenesis of osteoarthritis (OA) either directly or through the stimulation of catabolic factors. The action of IL-1 on articular cartilage is multifaceted and it most likely plays an important role in the mechanism of cartilage destruction. IL-1 suppresses the synthesis of the cartilage matrix components and promotes the degradation of cartilage matrix macromolecules. Diacerein is an anthraquinone molecule that has been shown to reduce the severity of OA, both in man and in animal models. The present study was designed to evaluate in vitro effects of diacerein on IL-1beta expression in LPS or IL-1alpha stimulated chondrocytes. Intracellular IL-1beta production was analysed in articular chondrocytes cultured in monolayer or in alginate 3D-biosystems in the presence of lipopolysaccharide (LPS) or IL-1alpha, with or without diacerein. The results show that LPS and IL-1alpha increase intracellular IL-1beta and Diacerein inhibited LPS-induced and IL-1alpha induced IL-1beta production by articular chondrocytes. Moreover, the effect of mechanical stimulation was analysed. An inhibitory effect of DAR at therapeutic concentrations on IL-1beta production in articular chondrocytes is suggested.

Alginates↗
PubMedDate not supplied

Introduction to hemorheology: theoretical aspects and hyperviscosity syndromes.

Whole blood behaves like a deformable colloidal particle suspension in a macromolecular medium. Pathological variations in the rheological properties of blood and the clinical symptoms they produce form the "hyperviscosity syndromes". The term "hyperviscosity" was originally used for characterising the plasma hyperviscosity observed during macroglobulinemia and it is only recently that the chapter covering hyperviscosity syndrome has been enlarged to describe the syndromes as a state which the increased blood viscosity and increase in flow resistance must be considered as the result of the rheological behaviour of blood taken as a whole (plasma and blood cells). The etiology of hyperviscosity syndromes can be: (a) an increase in total plasma protein levels, or the appearance of a monoclonal protein; (b) the increase in the number of blood cells; (c) the increase in the erythrocyte's internal viscosity; (d) the changes in the erythrocyte's viscoelastic properties; (e) the excessive aggregating tendency of the erythrocytes and perhaps that of the platelets.

Blood Proteins↗
PubMedDate not supplied

Erythrocyte aggregation: experimental approaches and clinical implications.

From a clinical point of view, quantitative studies of erythrocyte aggregation or rouleau formation is of great interest. However, in order to approach the phenomenon, structural parameters (rouleau shape), kinetic parameters (rouleau formation and dissociation velocity) and rheological parameters (dissociation thresholds) must be determined. At present, optical dynamic methods are available for use in clinical hemorheology. They involve optical measurements in a viscometer. The first method consists of a study of the light intensity transmitted through the measuring chamber of a cone plan viscometer. A device calculates and index I, which provides a whole approach to the aggregation kinetics. On the other hand, a systemic which also involves a cone-plain viscometer and an inverted microscope (Rheoscope) allows to collect data by means of microphotographs, microcinematography or numerical image processing. In that case, an adimensional K index typical of the morphology of the aggregates can be determined. The second method involves the analysis of the light intensity backscattered by the red blood cells sheared in a Couette flow. An automatic system has been developed and aggregation times, orientation and structure index, total and partial disaggregation thresholds can be determined on the basis of the curves of variations of backscattered light.

Blood Viscosity↗